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1 Page 1 of 595 First Revision No. 124-NFPA [ Global Input ] Revise all fuel gas system diagrams in mandatory and annex sections to identify the equipment isolation valve or valves. Change "Outside Boiler Room" label to indicate "NFPA 85 scope" and "Other Piping Code" scope. Supplemental Information File Name FR124_Figures_Update.pdf Description Updated figures showing T(e) manual equipment isolation valve. Submitter Full Name: [ Not Specified ] Organization: [ Not Specified ] Submittal Date: Wed Jan 30 10:25:41 EST 2013 The figures are updated to be consistent with new provisions for equipment isolation valves.

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11 Page 2 of 595 First Revision No. 9-NFPA [ Global Input ] Chapter 8 change - replace "stop valve or equivalent valve" with "safety shutoff valve" everywhere it appears. Submitter Full Name: Jenny Depew Organization: NFPA Submittal Date: Fri Jan 11 11:11:29 EST 2013 The committee replaced the term "stop valve" with "safety shutoff valve" for consistency with the rest of the document and NFPA 37. The committee removed the reference to "equivalent valves" because, for a duct burner system, only safety shutoff valves are used to stop fuel flow. It is the intent of the committee to enable designers and/or operators to use the individual burner safety shutoff valve, where provided in accordance with , as the most downstream safety shutoff valve when it is not practical to install the third shutoff valve in the main fuel supply line. The previous text was worded to require the individual burner safety shutoff valves to be used as the "third valve".

12 Page 3 of 595 First Revision No. 78-NFPA [ New Section after ] Inspections required by or conducted in accordance with this code shall be the responsibility of the owner/operator or designated representative. Submitter Full Name: [ Not Specified ] Organization: [ Not Specified ] Submittal Date: Tue Jan 29 15:12:55 EST 2013 It was reported to the committee that some jurisdictions were misapplying responsibility for inspections to the jurisdictional boiler inspector. The intent of the committee is that all inspections required by NFPA 85 are the responsibility of the boiler owner/operator. Public Input No. 136-NFPA [Section No ] Public Input No. 138-NFPA [Section No. A ] Public Input No. 140-NFPA [Section No ] Public Input No. 141-NFPA [Section No ] Public Input No. 142-NFPA [Section No ] Public Input No. 143-NFPA [Section No ] Public Input No. 147-NFPA [Section No. A (2)] Public Input No. 148-NFPA [Section No ] Public Input No. 149-NFPA [Section No. A (2)] Public Input No. 150-NFPA [Section No ] Public Input No. 153-NFPA [Section No ] Public Input No. 155-NFPA [Section No (C)] Public Input No. 156-NFPA [Section No ] Public Input No. 157-NFPA [Section No. L.2.2] Public Input No. 158-NFPA [Section No ] Public Input No. 159-NFPA [Section No ] Public Input No. 160-NFPA [Section No ] Public Input No. 166-NFPA [Section No ] Public Input No. 167-NFPA [Section No ] Public Input No. 169-NFPA [Section No. A ] Public Input No. 170-NFPA [Section No. A (4)] Public Input No. 171-NFPA [Section No. A ] Public Input No. 172-NFPA [Section No. A ] Public Input No. 173-NFPA [Section No. B.3.4.1] Public Input No. 174-NFPA [Section No. C.1.5.1]

13 Page 4 of 595 Public Input No. 175-NFPA [Section No. C.2.5.1] Public Input No. 176-NFPA [Section No. J.3] Public Input No. 177-NFPA [Section No. J.5]

14 Page 5 of 595 First Revision No. 116-NFPA [ Section No. 2.2 ] 2.2 NFPA Publications. National Fire Protection Association, 1 Batterymarch Park, Quincy, MA NFPA 30, Flammable and Combustible Liquids Code, edition. NFPA 31, Standard for the Installation of Oil-Burning Equipment, edition. NFPA 54, National Fuel Gas Code, edition. NFPA 56 Standard for Fire and Explosion Prevention During Cleaning and Purging of Flammable Gas Piping Systems, 2014 edition. NFPA 68 Standard on Explosion Protection by Deflagration Venting, 2013 edition. NFPA 69, Standard on Explosion Prevention Systems, 2008 edition. NFPA 70, National Electrical Code, edition. Submitter Full Name: [ Not Specified ] Organization: [ Not Specified ] Submittal Date: Tue Jan 29 21:25:24 EST 2013 The publication dates are updated to reflect current editions. Notes: Date Submitted By Apr 2, 2013 Apr 4, 2013 Apr 4, 2013 K. Ritchie RE: NFPA 70 - because 70 is in the current cycle (A13), change to 2014 edition date, or leave as 2011? K. Ritchie NFPA 56 - added to refs as it was cited in new (FR-120) K. Ritchie NFPA 68 - added to refs as it was cited throughout new Ch. 9 text

15 Page 6 of 595 First Revision No. 117-NFPA [ Section No ] ASCE Publications. American Society of Civil Engineers, 1801 Alexander Bell Drive, Reston, VA ASCE 7, Minimum Design Loads for Buildings and Other Structures, Submitter Full Name: [ Not Specified ] Organization: [ Not Specified ] Submittal Date: Tue Jan 29 21:27:18 EST 2013 The publication dates are updated to reflect current editions.

16 Page 7 of 595 First Revision No. 118-NFPA [ Section No ] ASME Publications. American Society of Mechanical Engineers, Three Park Avenue, New York, NY ASME B31.1, Power Piping, ASME B31.3, Process Piping, Submitter Full Name: [ Not Specified ] Organization: [ Not Specified ] Submittal Date: Tue Jan 29 21:27:58 EST 2013 The publication dates are updated to reflect current editions.

17 Page 8 of 595 First Revision No. 79-NFPA [ Section No ] ASTM Publications. ASTM International, 100 Barr Harbor Drive, P.O. Box C700, West Conshohocken, PA ASTM D 388, Standard Classification of Coals by Rank, ASTM D 396, Standard Specification for Fuel Oils, ASTM D 409, Standard Test Method for Grindability of Coal by the Hardgrove- Machine Method, ASTM D 1655, Standard Specification for Aviation Turbine Fuels, ASTM D 2880, Standard Specification for Gas Turbine Fuel Oils, 2003, reaffirmed Submitter Full Name: [ Not Specified ] Organization: [ Not Specified ] Submittal Date: Tue Jan 29 15:39:03 EST 2013 The publication dates of the referenced standards are updated to the current editions. Public Input No. 130-NFPA [Section No ]

18 Page 9 of 595 First Revision No. 119-NFPA [ Section No. 2.4 ] 2.4 References for Extracts in Mandatory Sections. NFPA 13D, Standard for the Installation of Sprinkler Systems in One- and Two- Family Dwellings and Manufactured Homes, edition. NFPA 40, Standard for the Storage and Handling of Cellulose Nitrate Film, edition. NFPA 72, National Fire Alarm and Signaling Code, edition. NFPA 850, Recommended Practice for Fire Protection for Electric Generating Plants and High Voltage Direct Current Converter Stations, 2010 edition. Submitter Full Name: [ Not Specified ] Organization: [ Not Specified ] Submittal Date: Tue Jan 29 21:34:22 EST 2013 The publication dates are updated to reflect current editions.

19 Page 10 of 595 First Revision No. 3-NFPA [ Section No ] Agglomeration. Alkali compounds can attach to bed material particles. These compounds can have low melting points and cause the bed particles to stick to each other to form agglomerates. Submitter Full Name: SUSAN BALLESTER Organization: NFPA Submittal Date: Thu Jan 10 14:40:07 EST 2013 The committee deleted the definition because it is information specific to the use of the term "agglomeration" in chapter 7; not a general definition. The BCS-FUN committee encourages the BCS-FBB committee to consider using the definition as a basis for annex material to (6), as it is the only usage in the document.

20 Page 11 of 595 First Revision No. 2-NFPA [ New Section after ] Competent Person. One who is capable of identifying existing and predictable hazards in the surroundings or working conditions that are unsanitary, hazardous, or dangerous to employees, and who has authorization to take prompt corrective measures to eliminate them. [29 CFR (f)] Submitter Full Name: SUSAN BALLESTER Organization: NFPA Submittal Date: Thu Jan 10 14:34:10 EST 2013 To support the use of the term "competent person" in new paragraph 4.5.5(A). Notes: Date Submitted By Apr 2, 2013 K. Ritchie 3.3.x - this new definition has been positioned as a sub-definition under "Air," which seems incorrect. Delete definition from this spot and keep the other instance of this same definition " Competent Person" (see FR-149)?

21 Page 12 of 595 First Revision No. 58-NFPA [ Section No ] * Excess Air. Air supplied for combustion in excess of theoretical air the stoichiometric mixture of air and fuel. Submitter Full Name: [ Not Specified ] Organization: [ Not Specified ] Submittal Date: Tue Jan 29 11:28:51 EST 2013 The definition is revised editorially to use the term stoichiometric mixture instead of theoretical air. The definition for theoretical air was deleted in a separate action.

22 5/17/13 TerraView First Revision No. 80-NFPA [ Section No ] Primary Air (for the purposes of equipment within the scope of Chapter 8). The air that is contained in the combustion turbine exhaust. Submitter Full Name: [ Not Specified ] Organization: [ Not Specified ] Submittal Date: Tue Jan 29 15:55:52 EST 2013 The phrase Primary Air (for the purposes of equipment within the scope of Chapter 8) is not used in chapter 8. Public Input No. 184-NFPA [Section No ] submittals.nfpa.org/terraviewweb/viewerpage.jsp 1/1

23 Page 14 of 595 First Revision No. 57-NFPA [ Section No ] Theoretical Air. The chemically correct quantity of air needed for complete combustion of a given quantity of a specific fuel. Submitter Full Name: [ Not Specified ] Organization: [ Not Specified ] Submittal Date: Tue Jan 29 11:27:07 EST 2013 The term is used only in the definition for "Excess Air." The definition for excess air is revised to remove the term entirely.

24 Page 15 of 595 First Revision No. 59-NFPA [ Section No ] Atmospheric Fluidized- Bed Combustion. A fuel-firing technique using a fluidized bed operating at near-atmospheric pressure on the fire side. Submitter Full Name: [ Not Specified ] Organization: [ Not Specified ] Submittal Date: Tue Jan 29 11:54:15 EST 2013 The hyphen between fluidized and bed is removed to match the usage in the subject chapter.

25 Page 16 of 595 First Revision No. 60-NFPA [ Section No ] Bottom Air Admission. A method of introducing air to a chain or traveling grate stoker under the stoker. Submitter Full Name: [ Not Specified ] Organization: [ Not Specified ] Submittal Date: Tue Jan 29 11:55:44 EST 2013 The definition is deleted because the term is not used in the mandatory text. The committee notes that the term is used in Annex G, and it may be appropriate to add the definition there.

26 Page 17 of 595 First Revision No. 61-NFPA [ Section No ] Auxiliary Load-Carrying Burner. In a fluidized bed boiler, a burner whose primary purpose is load carrying, that is located over the bed, and that has its own air supply. Submitter Full Name: [ Not Specified ] Organization: [ Not Specified ] Submittal Date: Tue Jan 29 11:59:14 EST 2013 The definition is deleted because the term is not used in the mandatory text of the code.

27 Page 18 of 595 First Revision No. 62-NFPA [ Section No ] Over Bed Burner. In a fluidized bed boiler, a warm-up burner located above the bed and firing over or into the bed. Submitter Full Name: [ Not Specified ] Organization: [ Not Specified ] Submittal Date: Tue Jan 29 12:01:32 EST 2013 The definition is deleted because the term is not used in the mandatory text of the code.

28 Page 19 of 595 First Revision No. 63-NFPA [ Section No ] Warm-Up Burner (in a Fluidized-Bed Boiler). A burner having its own air supply used to warm up the bed to the ignition temperature of the main fuel. The warm-up burner also can be used for limited load carrying Warm-Up Burner (Warm-Up Gun). A burner, usually smaller than the main burner, that is ignited by another ignition source and used to warm up the boiler. In cases where it is used as an igniter, its classification is verified by test Warm-Up Burner (in a Fluidized Bed Boiler). A burner having its own air supply used to warm up the bed to the ignition temperature of the main fuel. The warm-up burner also can be used for limited load carrying. Submitter Full Name: [ Not Specified ] Organization: [ Not Specified ] Submittal Date: Tue Jan 29 12:07:03 EST 2013 The term warm-up burner is used only in the context of fluidized bed boilers. Therefore, the parent definition is deleted and the specific definition is elevated.

29 Page 20 of 595 First Revision No. 64-NFPA [ Sections , ] Manual Burner Management System. A burner management system by which a furnace is purged and a burner is started, ignited, and stopped manually Manual, Supervised Burner Management System. A burner management system by which a furnace is purged and a burner is started, ignited, and stopped manually. Interlocks are included to ensure that the operation follows established, proper procedures. Submitter Full Name: [ Not Specified ] Organization: [ Not Specified ] Submittal Date: Tue Jan 29 12:18:01 EST 2013 The terms are not consistently used in the mandatory text. Therefore, the definitions are deleted and the subject committees are encouraged to revise their text for consistency and provide annex material where needed.

30 Page 21 of 595 First Revision No. 65-NFPA [ Section No ] Calcination. The endothermic chemical reaction that takes place when converting calcium carbonate or calcium hydroxide to calcium oxide. Submitter Full Name: [ Not Specified ] Organization: [ Not Specified ] Submittal Date: Tue Jan 29 12:19:59 EST 2013 The definition is deleted because the term is not used in the mandatory text of the code.

31 Page 22 of 595 First Revision No. 66-NFPA [ Section No ] Calcium to Sulfur Molar Ratio (Ca/S). The ratio of the total moles of calcium in the sorbent fed to the boiler to the total moles of sulfur in the fuel fed to the boiler. Submitter Full Name: [ Not Specified ] Organization: [ Not Specified ] Submittal Date: Tue Jan 29 12:21:33 EST 2013 The definition is deleted because the term is not used in the mandatory text of the code.

32 Page 23 of 595 First Revision No. 68-NFPA [ Section No ] Cinder Return. In a stoker-fired boiler, an apparatus for the return of collected cinders to the furnace, either directly or with the fuel. Submitter Full Name: [ Not Specified ] Organization: [ Not Specified ] Submittal Date: Tue Jan 29 12:23:56 EST 2013 The definition is deleted because the term is not used in the mandatory text of the code. The committee notes that the term is used in annex material and the definition may be appropriate in that annex text.

33 Page 24 of 595 First Revision No. 69-NFPA [ Section No ] Coking Plate. A plate adjacent to a grate through which no air passes and on which coal is placed for distilling the coal volatiles before the coal is moved onto the grate. Submitter Full Name: [ Not Specified ] Organization: [ Not Specified ] Submittal Date: Tue Jan 29 12:24:57 EST 2013 The definition is deleted because the term is not used in the mandatory text of the code.

34 Page 25 of 595 First Revision No. 70-NFPA [ Section No ] Combustion Turbine Runback. The controlled unloading of a combustion turbine to a level required by HRSG or other equipment control demands. Submitter Full Name: [ Not Specified ] Organization: [ Not Specified ] Submittal Date: Tue Jan 29 12:25:42 EST 2013 The definition is deleted because the term is not used in the mandatory text of the code. The committee notes that the term appears in the annex, and the definition may be appropriate for annex material.

35 Page 26 of 595 First Revision No. 81-NFPA [ Section No ] Combustion Control System in HRSG Systems. In HRSG systems, the control system that regulates the fuel input and air, where applicable, to maintain continuous combustion and stable flame. Submitter Full Name: [ Not Specified ] Organization: [ Not Specified ] Submittal Date: Tue Jan 29 16:02:00 EST 2013 The term is deleted because it is not used in the mandatory code text. Public Input No. 187-NFPA [Section No ]

36 Page 27 of 595 First Revision No. 82-NFPA [ Section No ] HRSG Control System. The group of control systems that regulate the HRSG process, including the combustion control system to maintain continuous combustion and stable flame, but not the burner management system. Submitter Full Name: [ Not Specified ] Organization: [ Not Specified ] Submittal Date: Tue Jan 29 16:03:04 EST 2013 The term "combustion control system" was eliminated to prevent any confusion of fuel/air control concepts. The phrase "to maintain continuous combustion and stable flame" from was moved to to retain this functional part of the definition for combustion control system.

37 Page 28 of 595 First Revision No. 71-NFPA [ Section No ] Start-Up Combustion Control System. A control system used to regulate and maintain proper air-fuel ratio during the start-up period where the customary indexes, such as pressure, temperature, load, or flow, that motivate the normal automatic combustion control system are not available or suitable. Submitter Full Name: [ Not Specified ] Organization: [ Not Specified ] Submittal Date: Tue Jan 29 12:27:00 EST 2013 The definition is deleted because the term does not appear in the mandatory text of the code.

38 Page 29 of 595 First Revision No. 72-NFPA [ Section No ] Direct- Fired System (Unit System). A system in which the fuel is pulverized and delivered in suspension directly to the burner(s). Submitter Full Name: [ Not Specified ] Organization: [ Not Specified ] Submittal Date: Tue Jan 29 12:27:41 EST 2013 The definition is revised to be consistent with the usage in chapter 9. The MBB and PFS committees are encouraged to make the language consistent throughout chapters 6 and 9.

39 Page 30 of 595 First Revision No. 73-NFPA [ Section No ] Distributor/Divider. A device that splits a single stream of pulverized coal and primary air into two or more streams. Submitter Full Name: [ Not Specified ] Organization: [ Not Specified ] Submittal Date: Tue Jan 29 12:35:11 EST 2013 The definition is revised to reflect the usage in chapter 9. The PFS committee is encouraged to revise Figure (c) to be consistent with code language.

40 Page 31 of 595 First Revision No. 87-NFPA [ Section No ] Drag Seal. In a chain grate stoker, the hinged plate resting against the returning chain and used to seal the air compartments. Submitter Full Name: [ Not Specified ] Organization: [ Not Specified ] Submittal Date: Tue Jan 29 20:50:08 EST 2013 The definition is deleted because the term is not used in the mandatory text of the code.

41 Page 32 of 595 First Revision No. 88-NFPA [ Section No ] Dump Plate. In a stoker-fired furnace, an ash-supporting plate from which ashes can be discharged from one side of the plate by rotation of the plate. Submitter Full Name: [ Not Specified ] Organization: [ Not Specified ] Submittal Date: Tue Jan 29 20:50:58 EST 2013 The definition is deleted because the term is not used in the mandatory text of the code.

42 Page 33 of 595 First Revision No. 89-NFPA [ Section No ] Elutriation. The selective removal of fine solids from a fluidized bed by entrainment in the upward flowing products of combustion. Submitter Full Name: [ Not Specified ] Organization: [ Not Specified ] Submittal Date: Tue Jan 29 20:51:28 EST 2013 The definition is deleted because the term is not used in the mandatory text of the code.

43 Page 34 of 595 First Revision No. 1-NFPA [ Section No ] Induced Draft (ID) Fan. A device, downstream of the combustion process, used to remove the products of combustion from the boiler or HRSG by introducing a negative pressure differential HRSG, or flue gas ductwork. Submitter Full Name: SUSAN BALLESTER Organization: NFPA Submittal Date: Thu Jan 10 14:23:37 EST 2013 The committee determined that any reference to pressure differential is non-descriptive. Therefore, the definition is revised to the purpose of the fan rather than how it is accomplished. Public Input No. 77-NFPA [Section No ]

44 Page 35 of 595 First Revision No. 90-NFPA [ Section No ] Seal Air Fan. A fan used to supply sealing air. Submitter Full Name: [ Not Specified ] Organization: [ Not Specified ] Submittal Date: Tue Jan 29 20:52:08 EST 2013 The definition is deleted because the term is not used in the mandatory text of the code.

45 Page 36 of 595 First Revision No. 77-NFPA [ Section No ] Test Block Capability. The point on the fan head versus flow characteristic curve at which the fan is selected. This is the calculated operating point associated with the maximum continuous rating of the boiler or HRSG, plus the head and flow margins. Submitter Full Name: [ Not Specified ] Organization: [ Not Specified ] Submittal Date: Tue Jan 29 14:10:00 EST 2013 The term is revised to be consistent with usage in the subject chapters.

46 Page 37 of 595 First Revision No. 83-NFPA [ New Section after ] Flashback. A recession of flame to an unwanted position (e.g., into a fuel transport pipe). Submitter Full Name: [ Not Specified ] Organization: [ Not Specified ] Submittal Date: Tue Jan 29 16:09:19 EST 2013 Notes: Date Submitted By Apr 3, 2013 The term "flashback" is used repeatedly in chapter 9. The source of the definition is the Merriam-Webster dictionary. The BCS-PFS committee requested that the definition be added to NFPA 85 for the convenience of the user. K. Ritchie this part of the Flashback definition is explanatory in nature. Consider rephrasing the text within parentheses and moving it to Annex A?

47 Page 38 of 595 First Revision No. 91-NFPA [ Section No ] Fly Carbon Reinjection. In a stoker-fired boiler, the process of removing the coarse carbon-bearing particles from the particulate matter carried over from the furnace and returning the carbonaceous material to the furnace to be combusted. Submitter Full Name: [ Not Specified ] Organization: [ Not Specified ] Submittal Date: Tue Jan 29 20:52:47 EST 2013 The definition is deleted because the term is not used in the mandatory text of the code.

48 Page 39 of 595 First Revision No. 92-NFPA [ Section No ] Friability. The tendency of coal to crumble or break into small pieces. Submitter Full Name: [ Not Specified ] Organization: [ Not Specified ] Submittal Date: Tue Jan 29 20:53:56 EST 2013 The definition is deleted because the term is not used in the mandatory text of the code.

49 Page 40 of 595 First Revision No. 93-NFPA [ Section No ] Hogged Fuel. Wood refuse that has been chipped or shredded by a machine known as a hog. Submitter Full Name: [ Not Specified ] Organization: [ Not Specified ] Submittal Date: Tue Jan 29 20:54:29 EST 2013 The definition is deleted because the term is not used in the mandatory text of the code. The committee notes that the term is used in Annex F and the definition may be appropriately relocated there.

50 Page 41 of 595 First Revision No. 94-NFPA [ Section No ] Supplementary Fuel. Fuel burned to supply additional heat to the steam generator or to support combustion. Submitter Full Name: [ Not Specified ] Organization: [ Not Specified ] Submittal Date: Tue Jan 29 20:55:53 EST 2013 The definition is deleted because the term is not used in the mandatory text of the code.

51 Page 42 of 595 First Revision No. 5-NFPA [ Section No ] Gate (for Raw Fuel) (Silo Gate; Bunker Gate). A shutoff gate between the raw-fuel bunker and the raw-fuel feeder. Submitter Full Name: Kimberly Shea Organization: National Fire Protection Assoc Submittal Date: Fri Jan 11 10:49:08 EST 2013 The usage in context is clear, therefore, no definition is needed. In addition, the definition is circular and not very descriptive.

52 Page 43 of 595 First Revision No. 95-NFPA [ Sections , ] Bars or Keys Grate. Those parts of the fuel-supporting surface arranged to admit air for combustion Hand-Fired Grate. A grate on which fuel is placed manually, usually by means of a shovel. Submitter Full Name: [ Not Specified ] Organization: [ Not Specified ] Submittal Date: Tue Jan 29 20:56:58 EST 2013 The definitions are deleted because the terms are not used in the mandatory text of the code.

53 Page 44 of 595 First Revision No. 96-NFPA [ Section No ] Ledge Plate. A form of plate that is adjacent to and overlaps the edge of a stoker. Submitter Full Name: [ Not Specified ] Organization: [ Not Specified ] Submittal Date: Tue Jan 29 20:57:59 EST 2013 The definition is deleted because the term is not used in the mandatory text of the code.

54 Page 45 of 595 First Revision No. 97-NFPA [ Section No ] Low Fire. The minimum fire rate that results in stable combustion. Submitter Full Name: [ Not Specified ] Organization: [ Not Specified ] Submittal Date: Tue Jan 29 20:58:37 EST 2013 The definition is deleted because the term is not used in the mandatory text of the code.

55 Page 46 of 595 First Revision No. 98-NFPA [ Section No ] Main Fuel Temperature Permit. The minimum fluidized bed temperature at which the main fuel can be introduced with resulting stable combustion. Submitter Full Name: [ Not Specified ] Organization: [ Not Specified ] Submittal Date: Tue Jan 29 20:59:17 EST 2013 The definition is deleted because the term is not used in the mandatory text of the code.

56 Page 47 of 595 First Revision No. 99-NFPA [ Section No ] Minimum Fluidization Velocity. In a fluidized bed, the lowest velocity sufficient to cause incipient fluidization. Submitter Full Name: [ Not Specified ] Organization: [ Not Specified ] Submittal Date: Tue Jan 29 20:59:46 EST 2013 The definition is deleted because the term is not used in the mandatory text of the code.

57 Page 48 of 595 First Revision No. 100-NFPA [ Section No ] Recirculation (Solids or Recycle). The reintroduction of solid material extracted from the products of combustion into a fluidized bed. Submitter Full Name: [ Not Specified ] Organization: [ Not Specified ] Submittal Date: Tue Jan 29 21:00:33 EST 2013 The definition is deleted because the term is not used in the mandatory text of the code.

58 Page 49 of 595 First Revision No. 101-NFPA [ Section No ] Recycle Rate. In a fluidized bed, the rate at which a mass of material is reinjected into the bed. This value is often expressed as the ratio of the amount being reinjected to the total amount being elutriated from the fluidized bed. Submitter Full Name: [ Not Specified ] Organization: [ Not Specified ] Submittal Date: Tue Jan 29 21:01:55 EST 2013 The definition is deleted because the term is not used in the mandatory text of the code.

59 Page 50 of 595 First Revision No. 102-NFPA [ Section No ] Recycle Ratio. In a fluidized bed, the mass of material being reinjected into the bed divided by the mass of fuel being fed into the bed. Submitter Full Name: [ Not Specified ] Organization: [ Not Specified ] Submittal Date: Tue Jan 29 21:02:20 EST 2013 The definition is deleted because the term is not used in the mandatory text of the code.

60 Page 51 of 595 First Revision No. 74-NFPA [ Section No ] Air Register A set of dampers for a burner, or air supply system to a particular burner, used to distribute the combustion air admitted to the combustion chamber. Frequently controls the direction and velocity of the airstream for efficient mixing with the incoming fuel. Submitter Full Name: [ Not Specified ] Organization: [ Not Specified ] Submittal Date: Tue Jan 29 13:45:07 EST 2013 The term is revised to be consistent with the usage in the subject chapters.

61 Page 52 of 595 First Revision No. 103-NFPA [ Section No ] Reinjection. In a fluidized bed boiler, the return or recycling of material removed or carried from the furnace back to the furnace. Also refers to fly ash collected and returned to the furnace or combustion chamber, sometimes expressed as a percentage of the total collected. Submitter Full Name: [ Not Specified ] Organization: [ Not Specified ] Submittal Date: Tue Jan 29 21:04:48 EST 2013 The definition is deleted because the term is not used in the mandatory text of the code. The committee notes that the term appears only in Annex A, and the definition may be appropriately located there.

62 Page 53 of 595 First Revision No. 104-NFPA [ Section No ] Repeatability. The ability of a device to maintain a constant set point characteristic. Submitter Full Name: [ Not Specified ] Organization: [ Not Specified ] Submittal Date: Tue Jan 29 21:05:34 EST 2013 The definition is deleted because the term is not used in the mandatory text of the code.

63 Page 54 of 595 First Revision No. 105-NFPA [ Section No ] Retort. A trough or channel in an underfeed stoker, extending within the furnace, through which fuel is forced upward into the fuel bed. Submitter Full Name: [ Not Specified ] Organization: [ Not Specified ] Submittal Date: Tue Jan 29 21:06:10 EST 2013 The definition is deleted because the term is not used in the mandatory text of the code. The committee notes that the term appears in Annex G and the definition may be appropriately relocated there.

64 Page 55 of 595 First Revision No. 106-NFPA [ Section No ] Safety Shutdown Trip Relay. See , Master Fuel Trip Relay. Submitter Full Name: [ Not Specified ] Organization: [ Not Specified ] Submittal Date: Tue Jan 29 21:07:21 EST 2013 The definition is deleted because the term is not used in the mandatory text of the code.

65 Page 56 of 595 First Revision No. 6-NFPA [ Section No ] Combustion Turbine Normal Shutdown. The normal sequence of events that automatically provides successful shutdown of the combustion turbine with no abnormal conditions in the combustion system. Submitter Full Name: Kimberly Shea Organization: National Fire Protection Assoc Submittal Date: Fri Jan 11 10:50:25 EST 2013 There are a number of situations not related to the combustion system for which the turbine controller will reduce the power to full speed no load, force the line breaker open, then perform a full unit shutdown using the normal shutdown sequence. It is the intent of the committee that abnormal conditions in auxiliary systems and other systems unrelated to combustion do not impact the eligibility for combustion turbine purge credit.

66 Page 57 of 595 First Revision No. 84-NFPA [ Section No ] Emergency Shutdown (HRSG or other combustion turbine exhaust systems). An event resulting in the rapid shutoff of all fuel to the combustion turbine along with a master fuel trip. Submitter Full Name: [ Not Specified ] Organization: [ Not Specified ] Submittal Date: Tue Jan 29 16:25:26 EST 2013 No use of this phrase for combustion turbines was found in chapter 8 requiring a unique definition for the combustion turbine. One occurrence of Emergency Shutdown in chapter 8 is Duct Burner Emergency Shutdown, but that does not warrant a special definition. Public Input No. 190-NFPA [Section No ]

67 Page 58 of 595 First Revision No. 107-NFPA [ Section No ] Side Air Admission. Admission of air to the underside of a grate from the sides of a chain or traveling grate stoker. Submitter Full Name: [ Not Specified ] Organization: [ Not Specified ] Submittal Date: Tue Jan 29 21:07:56 EST 2013 The definition is deleted because the term is not used in the mandatory text of the code.

68 Page 59 of 595 First Revision No. 108-NFPA [ Section No ] Spent Bed Material. In a fluidized bed boiler, material removed from the bed generally comprising reacted sorbent, calcined limestone, ash, and solid, unburned combustibles. For some applications, the spent bed material might also contain some inert material, such as sand. Submitter Full Name: [ Not Specified ] Organization: [ Not Specified ] Submittal Date: Tue Jan 29 21:08:26 EST 2013 The definition is deleted because the term is not used in the mandatory text of the code.

69 Page 60 of 595 First Revision No. 7-NFPA [ Section No ] Steam Generator. A pressure vessel in which water is converted to steam or steam is superheated, or in which any combination thereof takes place. Submitter Full Name: Kimberly Shea Organization: National Fire Protection Assoc Submittal Date: Fri Jan 11 10:51:12 EST 2013 The term steam generator, excluding as part of a HRSG, is used only in section Section 4.12 is revised in FR-12 to remove this usage, therefore the definition is no longer needed.

70 Page 61 of 595 First Revision No. 109-NFPA [ Section No ] Steam Generator Capacity. The manufacturer's stated steam output rate over a period of time for which the steam generator is designed to operate. Submitter Full Name: [ Not Specified ] Organization: [ Not Specified ] Submittal Date: Tue Jan 29 21:09:06 EST 2013 The definition is deleted because the term is not used in the mandatory text of the code.

71 Page 62 of 595 First Revision No. 110-NFPA [ Section No ] Steam Generator Enclosure. The physical boundary for all steam generator pressure parts and the combustion process. Submitter Full Name: [ Not Specified ] Organization: [ Not Specified ] Submittal Date: Tue Jan 29 21:09:32 EST 2013 The definition is deleted because the term is not used in the mandatory text of the code.

72 Page 63 of 595 First Revision No. 111-NFPA [ Section No ] Stoker Chain Grate Stoker. A stoker that has a moving endless chain as a grate surface, onto which coal is fed directly from a hopper Dump Grate Stoker. A stoker equipped with movable ash trays, or grates, by means of which the ash is discharged at any desirable interval Forced Draft Stoker. A stoker in which the flow of air through the grate is caused by a pressure produced by mechanical means Front Discharge Stoker. A stoker so arranged that refuse is discharged from the grate surface at the same end as the coal feed Mechanical Stoker. A device consisting of a mechanically operated fuel feeding mechanism and a grate, used for the purpose of feeding solid fuel into a furnace, distributing it over a grate, admitting air to the fuel for the purpose of combustion, and providing a means for removal or discharge of refuse Multiple Retort Stoker. An underfeed stoker consisting of two or more retorts, parallel and adjacent to each other, but separated by a line of tuyeres, and arranged so that the refuse is discharged at the ends of the retorts Overfeed Stoker. A stoker in which fuel is fed onto grates above the point of air admission to the fuel bed. Overfeed stoker grates include the following: (1) Front Feed, Inclined Grate fuel is fed from the front onto a grate inclined downward toward the rear of the stoker; (2) Chain or Traveling Grate a moving endless grate that conveys fuel into and through the furnace where it is burned, after which it discharges the refuse; (3) Vibrating Grate an inclined vibrating grate in which fuel is conveyed into and through the furnace where it is burned, after which it discharges the refuse Rear Discharge Stoker. A stoker so arranged that ash is discharged from the grate surface at the end opposite the solid fuel Reciprocating Grate Stoker. A grate element that has reciprocating motion, usually for the purpose of fuel agitation or ash removal Side Dump Stoker. A stoker so arranged that refuse is discharged from a dump plate at the side of the stoker Single Retort Stoker. An underfeed stoker using one retort only in the assembly of a complete stoker Spreader Stoker.

73 Page 64 of 595 A stoker that distributes fuel into the furnace from a location above the fuel bed with a portion of the fuel burned in suspension and a portion on the grates. Spreader stoker grates include the following: (1) Stationary Grate a grate in which fuel is fed onto a fixed position grate; (2) Dump Grate a grate in which fuel is fed onto a nonmoving grate that is arranged to allow intermittent discharge of refuse through tilting action of the grate bars; and (3) Continuous Discharge or Traveling Grate a grate that continuously discharges the refuse from the end after burning the fuel Traveling Grate Stoker. A stoker similar to a chain grate stoker with the exception that the grate is separate from but is supported on and driven by chains Underfeed Stoker. A stoker in which fuel is introduced through retorts at a level below the location of air admission to the fuel bed. Underfeed stokers are divided into three general classes Continuous Ash Discharge Underfeed Stoker. A stoker in which the refuse is discharged continuously from the normally stationary stoker ash tray to the ash pit, without the use of mechanical means other than the normal action of the coal feeding and agitating mechanism Rear Discharge Underfeed Stoker. A stoker having a grate composed of transversely spaced underfeed retorts that feed and distribute solid fuel to intermediate rows of tuyeres through which air is admitted for combustion. The ash is discharged from the stoker across the rear end Side Ash Discharge Underfeed Stoker. A stoker having one or more retorts that feed and distribute fuel onto side tuyeres or a grate through which air is admitted for combustion and over which the ash is discharged at the side parallel to the retorts Water Cooled Stoker. A stoker having tubes in or near the grate surface through which water is passed for cooling the grates. Submitter Full Name: [ Not Specified ] Organization: [ Not Specified ] Submittal Date: Tue Jan 29 21:10:45 EST 2013 The definitions are deleted because the specific stoker designations are not used in the mandatory text of the code. The committee notes that discussion of specific types of stokers is located only in Annex G, and these definitions may be appropriately relocated there by the Stokers committee.

74 Page 65 of 595 First Revision No. 112-NFPA [ Section No ] Stoker Gate. An element of a stoker placed at the point of entrance of fuel into the furnace and by means of which the depth of fuel on the stoker grate is controlled. It is generally used in connection with chain or traveling grate stokers and has the form of a guillotine. Submitter Full Name: [ Not Specified ] Organization: [ Not Specified ] Submittal Date: Tue Jan 29 21:12:05 EST 2013 The definition is deleted because the term is not used in the mandatory text of the code.

75 Page 66 of 595 First Revision No. 67-NFPA [ Sections , , , ] Sulfation. The exothermic chemical reaction that takes place when calcium oxide unites with oxygen and sulfur dioxide to form calcium sulfate Sulfur Capture. The molar fraction of sulfur in the fuel input that is captured by calcium oxide to form calcium sulfate Sulfur Reacted. In a fluidized bed, the fraction of the total sulfur in the fuel fed to the bed that is converted to sulfur dioxide or calcium sulfate Sulfur Retention. The molar ratio of the total sulfur in the fuel minus the sulfur leaving the unit as sulfur dioxide to the total sulfur in the fuel. Submitter Full Name: [ Not Specified ] Organization: [ Not Specified ] Submittal Date: Tue Jan 29 12:22:48 EST 2013 The definitions are deleted because the terms are not used in the mandatory text of the code.

76 Page 67 of 595 First Revision No. 113-NFPA [ Section No ] Supplementary Firing. The provision of duct burners in a HRSG to increase the temperature of the combustion turbine exhaust gases. Submitter Full Name: [ Not Specified ] Organization: [ Not Specified ] Submittal Date: Tue Jan 29 21:19:14 EST 2013 The definition is deleted because the term is not used in the mandatory text of the code. The committee notes that the term appears in Annex A, and the definition may be appropriately relocated there.

77 Page 68 of 595 First Revision No. 147-NFPA [ Sections , , , , ] Normal Shutdown, High Steam Pressure Interlock. A pressure-actuated device that is arranged to effect a normal burner shutdown when the steam pressure exceeds a preset pressure Normal Shutdown, High Water Temperature Interlock. A temperature-actuated device that is arranged to effect a normal burner shutdown when the water temperature exceeds a preset temperature Process Monitoring, High Oil Temperature Interlock. A temperature-actuated device that initiates a signal when oil temperature rises above the limits that are required to maintain the viscosity range recommended by the burner manufacturer Process Monitoring, Low Oil Temperature Interlock. A temperature-actuated device that initiates a signal when the oil temperature falls below the limits that are required to maintain the viscosity range recommended by the burner manufacturer Proof of Closure Interlock. A device that provides feedback that a piece of equipment is in the closed position Safety Shutdown, Excessive Steam Pressure Interlock. A pressure-actuated device that is arranged to effect a safety shutdown of the burner when the steam pressure exceeds a preset pressure Safety Shutdown, Excessive Water Temperature Interlock. A temperature-actuated device that is arranged to effect a safety shutdown of the burner when the water temperature exceeds a preset temperature Safety Shutdown, High Gas Pressure Interlock. A pressure-actuated device that is arranged to effect a safety shutdown or to prevent starting when the gas pressure exceeds the preset value Safety Shutdown, Low Gas Pressure Interlock. A pressure-actuated device that is arranged to effect a safety shutdown or to prevent starting when the gas pressure falls below the preset value Safety Shutdown, Low Oil Pressure Interlock. A pressure-actuated device that is arranged to effect a safety shutdown or to prevent starting when the oil pressure falls below the preset value Safety Shutdown, Low Water Cutout Auxiliary Interlock. On single burner boilers, a device that is arranged to effect a safety shutdown of the burner when the water level in the boiler falls to a predetermined low level Safety Shutdown, Low Water Cutout Interlock. A device that is arranged to effect a safety shutdown or master fuel trip when the water level in the boiler or HRSG falls to a predetermined low level.

78 Page 69 of 595 Submitter Full Name: [ Not Specified ] Organization: [ Not Specified ] Submittal Date: Fri Feb 01 14:52:56 EST 2013 In accordance with section and its subparts, interlocks and alarms can be initiated by switches or transmitters. Retaining switch in the definitions creates confusion.

79 Page 70 of 595 First Revision No. 75-NFPA [ Sections , ] Trial for Ignition Period (Igniter). The interval of time during light-off in which a safety control circuit permits the igniter fuel safety shutoff valve(s) to be opened before the flame detection system is required to supervise the igniter flame Trial for Ignition Period (Main Burner). The interval of time during light-off in which a safety control circuit permits the main burner fuel safety shutoff valve(s) to be opened before the flame detection system is required to supervise the main burner flame only. Submitter Full Name: [ Not Specified ] Organization: [ Not Specified ] Submittal Date: Tue Jan 29 13:52:57 EST 2013 The definition is revised to be consistent with the usage in the mandatory code text.

80 Page 71 of 595 First Revision No. 122-NFPA [ New Section after ] Equipment Isolation Valve. A manual valve that separates the boiler, HRSG, or igniter fuel train from the fuel supply piping system. Submitter Full Name: [ Not Specified ] Organization: [ Not Specified ] Submittal Date: Wed Jan 30 09:43:26 EST 2013 The definition is added to support new requirements for providing an equipment isolation valve in chapter 4.

81 Page 72 of 595 First Revision No. 114-NFPA [ Section No ] Vent Control Valve. A controllable valve for regulating the flow of vented air or gas from the system. Submitter Full Name: [ Not Specified ] Organization: [ Not Specified ] Submittal Date: Tue Jan 29 21:21:24 EST 2013 The definition is deleted because the term is not used in the mandatory text of the code.

82 Page 73 of 595 First Revision No. 115-NFPA [ Section No ] Watch-Dog Timer. A timer external to a microprocessor-based control that is used to compare the microprocessor cycle timing against itself and that fails safely if the microprocessor timing stops or exceeds the watch-dog time interval. Submitter Full Name: [ Not Specified ] Organization: [ Not Specified ] Submittal Date: Tue Jan 29 21:21:57 EST 2013 The definition is deleted because the term is not used in the mandatory text of the code. The annex material A (1) was modified to include this definition.

83 Page 74 of 595 First Revision No. 85-NFPA [ New Section after ] 4.1.4* Unattended and Off-Site Operation. Unattended operation, no operator at the operating location(s), or operation of the plant from an off-site operating location shall be approved and shall require a process hazard analysis (PHA). Submitter Full Name: [ Not Specified ] Organization: [ Not Specified ] Submittal Date: Tue Jan 29 16:58:21 EST 2013 The committee adopted a requirement for process hazard analysis similar to what exists in the 2011 edition in chapter 6. The committee modified the chapter 6 language to incorporate the more recognized term of process hazard analysis, and created annex material to provide users with resources for further information. Public Input No. 76-NFPA [Section No ]

84 Page 75 of 595 First Revision No. 86-NFPA [ Section No ] Although this code requires a minimum degree of automation, more complex plants, plants with increased automation, and plants designed for remote operation shall require additional provisions for the following: (1) Information regarding significant operating events that allow the operator to make a rapid evaluation of the operating situation (2) Continuous and usable displays of variables that allow the operator to avoid hazardous conditions (3) In-service maintenance and checking of system functions without impairment of the reliability of the overall control system (4) An environment conducive to timely and correct decisions and actions Submitter Full Name: [ Not Specified ] Organization: [ Not Specified ] Submittal Date: Tue Jan 29 17:21:08 EST 2013 The text is deleted because it is unenforceable. The committee encourages public comments that revise the text to be enforceable or identify an appropriate location for it to be reinstated as annex material.

85 Page 76 of 595 First Revision No. 127-NFPA [ New Section after ] Burners and associated equipment shall be accessible for maintenance. Submitter Full Name: [ Not Specified ] Organization: [ Not Specified ] Submittal Date: Wed Jan 30 11:42:57 EST 2013 The burners and the associated equipment should be accessible for maintenance. This is similar to the requirement currently in and should be broadly applicable. Public Input No. 120-NFPA [New Section after ]

86 Page 77 of 595 First Revision No. 4-NFPA [ Section No ] 4.1.5* The burner or fuel feed piping and equipment shall be designed, constructed, and constructed located to prevent the formation of hazardous concentrations of combustible gases that exist combustibles under normal operating conditions * The installation of boilers or HRSGs, including the burners or fuel feed piping and equipment, in accordance with the requirements of this code shall not in and of itself determine the electrical classification. Submitter Full Name: SUSAN BALLESTER Organization: NFPA Submittal Date: Thu Jan 10 14:59:20 EST 2013 NFPA 497 section states "Open flames and hot surfaces associated with the operation of certain equipment, such as boilers and fired heaters, provide inherent thermal ignition sources. Electrical classification is not appropriate in the immediate vicinity of these facilities. However, it is prudent to avoid installing electrical equipment that could be a primary ignition source for potential leak sources in pumps, valves, and so forth, or in waste product and fuel feed lines." Therefore, NFPA 85 incorporates requirements for safe design and maintenance of equipment in its scope to maintain system integrity and minimize hazards related to fuel systems. However, there are many factors that should be considered in identifying electrically classified areas around such equipment. Users must use caution when identifying electrically classified areas and use appropriate recommended practices and good engineering judgment. Public Input No. 101-NFPA [Section No ]

87 Page 78 of 595 First Revision No. 141-NFPA [ Section No ] The safety interlock system and protective devices shall be tested jointly by the organization responsible for the system design and by those who operate and maintain such a system and devices. Submitter Full Name: [ Not Specified ] Organization: [ Not Specified ] Submittal Date: Wed Jan 30 17:06:37 EST 2013 The word safety is deleted because the requirement of clause applies to all types of interlock systems. Public Input No. 43-NFPA [Section No ]

88 5/17/13 TerraView First Revision No. 120-NFPA [ New Section after ] 4.2.7* Each time fuel gas is introduced to a fuel gas supply piping system containing air or inert gas upstream of the equipment isolation valve, the source of fuel gas in the piping system upstream of the equipment isolation valve shall be confirmed to be in compliance with the applicable evacuation/purging and charging requirements in NFPA 54, National Fuel Gas Code, or NFPA 56, Standard for Fire and Explosion Prevention During Cleaning and Purging of Flammable Gas Piping Systems. Submitter Full Name: [ Not Specified ] Organization: [ Not Specified ] Submittal Date: Wed Jan 30 09:07:09 EST 2013 Notes: Date Apr 3, 2013 Apr 8, 2013 The text is added to meet the request of the US Chemical Safety Board in follow up to hazards associated with fuel gas systems. Submitted By K. Ritchie changed 'the' to 'a' K. Ritchie asterisk added to indicate there is explanatory text at A Public Input No. 205-NFPA [New Section after 4.2.6] submittals.nfpa.org/terraviewweb/viewerpage.jsp 1/1

89 Page 80 of 595 First Revision No. 126-NFPA [ Section No ] As a minimum, the maintenance program shall include the following: (1) In-service i I nspections to identify conditions that need corrective action (2) Well-defined p P lanning for making repairs or modifications using qualified personnel and tools and instruments designed for the work (3) Equipment history and record of dates of service, conditions found, maintenance performed, and changes made (4) Written comprehensive maintenance procedures incorporating the manufacturer's instructions to define the tasks and skills required (5) Nondestructive examination requirements; tasks needing special tools; special environmental factors such as temperature limitations, dusts, contaminated or oxygen-deficient atmospheres, and limited access or confined space restrictions (6) Equipment condition assessment before and after maintenance (7) Supply of well-maintained spare parts to perform required maintenance (8) Housekeeping essential for safe operation and prevention of fires or explosions that includes the following: (a) Provisions for cleaning of horizontal ledges or surfaces of buildings and equipment to prevent the accumulation of dust deposits greater than the minimum required to create an explosion hazard (b) Water washing or vacuum cleaning methods to reduce the possibility of creating dust clouds (c) Prohibition of the use of compressed air for cleaning Submitter Full Name: [ Not Specified ] Organization: [ Not Specified ] Submittal Date: Wed Jan 30 11:21:29 EST 2013 The text is modified to remove unenforceable language. the term "Inservice" was also removed because it was being misinterpreted to require the inspections be performed by the jurisdictional inspector. Public Input No. 221-NFPA [Section No ] Public Input No. 139-NFPA [Section No ]

90 Page 81 of 595 First Revision No. 10-NFPA [ Section No ] No interlocks shall be bypassed during start-up or operation of the unit unless the bypass is tagged and is governed by operating procedures. The design shall not require any deliberate defeating of an interlock to start or operate equipment Interlock devices shall be permitted to be temporarily removed from service in accordance with the following: (1) Removal of the interlock shall be authorized by a competent person and documented in accordance with operating procedures. (2) Alternate means shall be substituted to supervise this interlock function in accordance with operating procedures. Submitter Full Name: Kimberly Shea Organization: National Fire Protection Assoc Submittal Date: Fri Jan 11 11:27:32 EST 2013 This language was extracted from at the suggestion of the BCS- AAC Technical Correlating. The BCS-FUN TC recognizes that interlocks may need to be bypassed to complete maintenance and testing. While the existing addresses this need, the language from the existing provides a more thorough treatment of the procedure for doing so. The existing chapter 6 language was modified because "annunciation" requires both visual and audible notification. The BCS-FUN committee determined that the company's operating procedures should be used to determine how operators document the override. The requirements were broken out into a subsection and paragraphs to comply with the Manual of Style. Notes: Date Submitted By Apr 3, 2013 K. Ritchie changed from lettered list to numbered list Public Input No. 103-NFPA [Section No ]

91 Page 82 of 595 First Revision No. 128-NFPA [ Section No ] * The arrangement of air inlets, ductwork, and air preheaters shall be designed to minimize contamination of the air supply by flue gas, water, fuel(s), and other materials as a result of either intentional or accidental discharges. Submitter Full Name: [ Not Specified ] Organization: [ Not Specified ] Submittal Date: Wed Jan 30 12:04:21 EST 2013 The paragraph is deleted because it is vague and unenforceable. Public Input No. 53-NFPA [Section No ]

92 Page 83 of 595 First Revision No. 35-NFPA [ Section No ] Boilers or HRSGs that share a common component between the furnace outlet and the stack shall be in accordance with the following: (1) There shall be provisions to bypass the common component for unit purge when the common component contains a possible ignition source. (2) A common component shall not interrupt the open-flow air path of a boiler or HRSG during operation or purge. (3) have provisions to bypass the common component for unit purge when the common component contains a possible ignition source. Submitter Full Name: Kimberly Shea Organization: National Fire Protection Assoc Submittal Date: Fri Jan 11 14:03:22 EST 2013 * A common component shall not permit the flow of combustion products into an idle boiler or HRSG. When two or more boiler outlets are tied together, it is possible to pressurize the connection point either by design or excursion. Positive pressure at the common component eliminates an open flow path ( ), permits products of combustion from a running unit to enter an idle unit, and also prevents the unburned fuel and products of combustion from exiting the combustion chamber and gas paths via passive means when fans are lost. This does not pertain to a specific type of equipment; it pertains to the requirements of any combustion products removal subsystem. Notes: Date Submitted By Apr 3, 2013 K. Ritchie changed from lettered list to numbered list

93 Page 84 of 595 First Revision No. 130-NFPA [ Section No. 4.8 ] 4.8 Multiple Boilers or HRSGs Where multiple boilers or HRSGs are supplied from the same fuel supply source, there shall be a means of manual isolation for each boiler and HRSG Dedicated safety shutoff valving, with related alarm, interlock, and control instrumentation, shall be provided for each boiler and HRSG. Submitter Full Name: [ Not Specified ] Organization: [ Not Specified ] Submittal Date: Wed Jan 30 12:15:13 EST 2013 Multiple HRSGs at a site are common. The requirements for fuel isolation to multiple boilers are also applicable to HRSGs. Public Input No. 191-NFPA [Section No. 4.8]

94 Page 85 of 595 First Revision No. 131-NFPA [ Section No ] 4.9.1* The discharge from atmospheric vents shall be located so that there is no possibility of the discharged gas being drawn into a combustion air intake, the ventilating system, away from occupied areas, sources of ignition, combustion air intakes, building ventilation systems, or the windows of the a boiler or HRSG room or adjacent buildings and shall be extended above the boiler or HRSG and adjacent structures so that gaseous discharge does not present a hazard. Submitter Full Name: [ Not Specified ] Organization: [ Not Specified ] Submittal Date: Wed Jan 30 12:16:29 EST 2013 The intent of this section is to ensure that atmospheric vents are routed to a safe location. These changes will provide additional guidance on what constitutes a safe location and is meant to incorporate aspects of sections 6.6.2(6) and in the 2011 edition. Public Input No. 59-NFPA [Section No ]

95 Page 86 of 595 First Revision No. 123-NFPA [ New Section after ] Equipment Isolation Valves. An equipment isolation valve shall be provided and shall be readily accessible at the fuel gas supply piping system connection Equipment isolation valves shall meet the following requirements: (1) They shall have permanently affixed visual indication of the valve position. (2) They shall be able to be operated from full open to full close and return without the use of tools. Submitter Full Name: [ Not Specified ] Organization: [ Not Specified ] Submittal Date: Wed Jan 30 10:20:01 EST 2013 The requirement is added to clearly identify the demarcation point between the scope of NFPA 85 and other codes and standards, particularly NFPA 54 and NFPA 56. In addition, it is not the intent to require an additional valve. It is the intent of the committee to designate the appropriate manual shutoff valve found in many of the diagrams as the equipment isolation valve.

96 Page 87 of 595 First Revision No. 132-NFPA [ Section No ] * Flue Gas Path Auxiliary Systems Fuel and Feedstock Piping, Oxidizer, and Combustible Reagent Piping. Positive means to prevent leakage of fuel or feedstock into an idle furnace or flue gas path shall be provided Flue gas path auxiliary systems shall be sulfur burner systems, ammonia injection systems, activated carbon injection systems, soot blowing or soot cleaning systems, and fired reheater systems Positive means to prevent leakage of fuel, oxidizer, or combustible reagent into an idle furnace or flue gas path shall be provided For gaseous fuels or feedstocks gaseous combustible reagents, provisions shall include a double block and vent valve arrangement on the fuel or feedstock gaseous combustible reagent supply, separate from any other double block and vent valve arrangements for other systems For oxidizers, provisions shall include a block valve on the oxidizer supply, separate from any other block valves for other systems For gaseous fuels or feedstocks gaseous combustible reagents, a double block and vent valve arrangement shall be provided in the fuel or feedstock gaseous combustible reagent line associated with each flue gas path injection point system For gaseous fuels or gaseous combustible reagents, each flue gas path injection system that can be operated independent of other flue gas path injection systems shall have its own double block and vent valve arrangement For liquid or blown-in powder fuels or feedstocks combustible reagents, provisions shall include a double block valve arrangement on the fuel or feedstock combustible reagent supply, separate from any other double block valve s arrangements for other systems. Submitter Full Name: [ Not Specified ] Organization: [ Not Specified ] Submittal Date: Wed Jan 30 13:28:14 EST 2013

97 Page 88 of 595 The text of applies to fuels and combustible reagents introduced into the furnace or flue gas path. It is not the intent of the committee to apply this subsection to limestone or trona (DSI systems) or steam (sootblowers) systems. Therefore, the language from the annex is brought forward to the mandatory text to describe which systems are subject to the requirements. The change also clarifies the number of block valves required. Since many Flue Gas Conditioning/Removal Systems are systems with multiple injection points, it is not the intent to require a double block and vent valve arrangement for each injection point into the furnace or flue. A double block valve arrangement for liquid and blown-in fuel is not necessary for auxiliary flue gas systems when the standard only requires a single block valve for oil or coal. Public Input No. 30-NFPA [Section No ] Public Input No. 64-NFPA [Section No ] Public Input No. 111-NFPA [Section No ] Public Input No. 193-NFPA [New Section after ] Public Input No. 242-NFPA [Section No ]

98 Page 89 of 595 First Revision No. 142-NFPA [ New Section after 4.11 ] Interlock System The basic requirement of an interlock system for a unit shall accomplish the following: (1) Protect personnel from injury (2) Protect equipment from damage (3) Protect boiler operation by limiting actions to a prescribed operating sequence or by initiating trip devices when approaching an out-of-range or unstable operating condition * Additional automatic trips shall be permitted Fuel-specific interlocks shall be provided for each design basis fuel * Operating personnel shall be made aware of the limitations of the interlock system. Submitter Full Name: [ Not Specified ] Organization: [ Not Specified ] Submittal Date: Wed Jan 30 17:10:51 EST 2013 The committee incorporated the general requirements of in Chapter 4. The requirements should be applicable to all boiler and HRSG interlock systems. Public Input No. 44-NFPA [New Section after 4.11]

99 Page 90 of 595 First Revision No. 13-NFPA [ Section No ] The burner management system interlock and alarm functions shall be initiated by one or more of the following: (1) One or more switches or transmitters switch or transmitter that are dedicated to the burner management system (2) One or both signals Voting logic derived from two transmitters exceeding a preset value or more switches or transmitters The median signal from three transmitters exceeding a preset value When multiple transmitters are used in the burner management system, such signals shall be permitted to be shared with other control systems for control purposes * When signals from multiple switches or transmitters are provided to initiate interlock or alarm functions, those signals shall be monitored in comparison to each other by divergence or other fault diagnostic alarms When signals from multiple switches or transmitters are provided to initiate interlock or alarm functions, the provided signals shall be generated by individual sensing devices connected to separate process taps. Submitter Full Name: Kimberly Shea Organization: National Fire Protection Assoc Submittal Date: Fri Jan 11 11:40:09 EST 2013 Notes: The BCS-FUN TC revised the language to recognize the use of voting systems. The median value is a sub-set of voting logic, therefore (2) and (3) are redundant to the new voting logic allowance. When only one switch or transmitter is utilized, it should be dedicated to the burner management system so that protection and control functions are not operating off of a single signal. When multiple transmitters are utilized, those signals can be shared for process control purposes. The committee does not find it realistic that switches would be shared with control systems for process control purposes.

100 Page 91 of 595 Date Apr 3, 2013 Apr 3, 2013 Submitted By K. Ritchie change 'When' to 'Where'? K. Ritchie change 'When' to 'Where'? Public Input No. 151-NFPA [Section No ]

101 Page 92 of 595 First Revision No. 134-NFPA [ Sections , ] Except as noted in , the The burner management system shall be provided with independent logic, independent logic solving hardware, independent input/output systems, and independent power supplies and shall be a device functionally and physically separate from other logic systems For single burner boilers, the boiler control system shall be permitted to be combined with the burner management system under one of the following conditions: (1) * If the fuel-air ratio is controlled externally from the boiler control system (2) If the combined boiler control and burner management system is specifically listed or labeled for the application Submitter Full Name: [ Not Specified ] Organization: [ Not Specified ] Submittal Date: Wed Jan 30 15:23:02 EST 2013 The committee deletes the paragraph because it is specific to single burner boilers. The BCS-SBB TC should consider adopting this or similar language in chapter 5 to retain this capability.

102 Page 93 of 595 First Revision No. 228-NFPA [ Section No ] For single burner boilers, the boiler control system shall be permitted to be combined with the burner management system under one of the following conditions: (1) (2) If the combined boiler control and burner management system is specifically listed or labeled for the application (3) * If the fuel-air ratio is controlled externally from the boiler control system * A single safety-rated programmable logic controller (PLC) shall be permitted to be used to implement both burner management system safety and process logic, if the processor and input/output (I/O) modules are approved or certified by a notified body to be at least SIL 2 capable according to IEC 61508, Functional Safety of Electrical/Electronic/Programmable Electronic Safety-Related Systems, when the burner management system logic is isolated from other logic and when the related data of the burner management system program are protected from being unintentionally affected by data of other user programs. Submitter Full Name: [ Not Specified ] Organization: [ Not Specified ] Submittal Date: Thu Mar 07 10:27:26 EST 2013

103 Page 94 of 595 The material was relocated to chapter 5 because it applies only to Single Burner Boilers. The First Revision is based on that PLC including a high level of fault detection based on it being a SIL 2 capable PLC with SIL 2 capable I/O modules as certified by a Notified Body, such as TUV or UL. a. This First Revision is based on the allowance in ISA and IEC61511 to implement both the safety and process functions in a single PLC when the system is not of a highly complex nature and where separation of the safety and process functions in a single safety rated PLC can be assured. b. The Notified Body or 3rd party certification is critical in the SIL 2 capable requirement because selfcertification is permitted in the safety rated PLC marketplace and with self - certification there is no assurance that critical safety functions, like the secure separation of the safety and process logic, are provided. c. The term Notified Body describes an independent body appointed by an agency within one of the European countries, usually governmental, as being capable of performing the duties of a notified body as defined by the directives. The primary role of a notified body is to provide services for conformity assessment. This means assessing the manufacturer s conformity to the essential requirements listed in each directive. d. The SIL 2 capable requirement pertains to the hardware and the firmware. It does not imply a SIL 2 functional safety implementation as required for a Safety Instrumented System under ISA and/or IEC In this context, SIL 2 capable pertains to the quality/reliability of the hardware and firmware to assure that there is assured separation between BMS safety logic and process logic. In other words, the BMS logic is securely protected from changes when process parameters or logic are accessed for change. e. This proposal is meant to allow the use of a single SIL 2 capable PLC processor and SIL 2 capable I/O modules to connect to the safety devices specified in NFPA 85 for a compliant control system implementation. At present, this could be done only if invoking the Equivalency provision. SIL 2 capable was purposely specified as the minimum safety level based on the existing safety levels presently required in NFPA 85. Notes: Date Submitted By Apr 3, 2013 Apr 3, 2013 K. Ritchie item '(3)' does not seem to fit within the numbered list of this requirement. Consider making item (3) a new sub-paragraph? K. Ritchie (3) - spelled out 'PLC' as it hasn't been used in code; spelled out 'BMS' as it hasn't been used in code; deleted '(a)' and '(b)' and ran in the text with rest of sentence; inserted title of 'IEC 61508' (pulled from NFPA 79 references) Public Input No. 212-NFPA [Section No ]

104 Page 95 of 595 First Revision No. 18-NFPA [ Section No [Excluding any Sub-Sections] ] Additional requirements concerning flame detection associated with each type of steam generator covered by this code are given in the respective chapters. Submitter Full Name: Kimberly Shea Organization: National Fire Protection Assoc Submittal Date: Fri Jan 11 12:03:55 EST 2013 The text was originally intended to provide a reminder to users of the combined code format that requirements in chapter 4 must be combined with requirements on the same topic in the equipment-specific chapters. The committee deleted the text because it does not provide a clear requirement, and users of the code should be familiar with the merged format.

105 Page 96 of 595 First Revision No. 135-NFPA [ Section No ] Flame Proving A flame detector shall not use any mechanical, electrical, or electronic means to force the flame detector into a flame not detected mode as part of the igniter and/or burner starting sequence A flame detector shall prove ignition of the associated fuel by proving both igniter flame not detected and burner flame not detected prior to introduction of the fuel to the igniter or burner and proving flame detected after introduction of that fuel to that igniter or burner An igniter flame detector shall not be required to prove flame not detected if the associated burner is proven in service and the associated igniter is out of service A burner flame detector shall not be required to prove flame not detected if an associated Class 1 igniter is proven in service The igniter flame detector(s) and/or the burner flame detector(s) shall not be required to prove flame not detected after the boiler load has been elevated to the point that it is no longer possible to achieve individual flame discrimination The boiler load specified in shall be proven by test to be the load level at which individual igniters and/or burner flame discrimination is no longer possible, but in no case shall the boiler load be less than that for which tests show that complete combustion will occur The response time from flame failure to the de-energization of the fuel safety shutoff devices shall not exceed 4 seconds, including any time delay associated with the flame detector. Submitter Full Name: [ Not Specified ] Organization: [ Not Specified ] Submittal Date: Wed Jan 30 15:41:51 EST 2013

106 Page 97 of 595 The committee added a requirement similar to the existing text for single burner boilers in paragraph The maximum response time is defined because it is an important factor for the boiler safety. It was reported to the committee that flame scanners have adjustments to comply with the applicable codes. Public Input No. 240-NFPA [Section No ]

107 Page 98 of 595 First Revision No. 136-NFPA [ Section No ] Except as noted in and ,, continuous trend display of steam flow rate, feedwater flow rate, total fuel flow rate, and total airflow rate as a percentage of the maximum unit load, drum level, final steam temperature, main steam pressure, and furnace or combustion chamber draft shall be simultaneously available at the operating location * For single burner boilers, continuous trend display of operating parameters critical to operation shall be provided For HRSGs, continuous trend display requirements are specified in Submitter Full Name: [ Not Specified ] Organization: [ Not Specified ] Submittal Date: Wed Jan 30 16:11:47 EST 2013 HRSGs do not require monitoring of total airflow rate as specified in Additionally, chapter 8 does not require trending of combustion chamber draft. Chapter 8 lists required trend displays for HRSGs in Public Input No. 135-NFPA [Section No [Excluding any Sub-Sections]] Public Input No. 194-NFPA [Section No ]

108 Page 99 of 595 First Revision No. 138-NFPA [ New Section after ] Alarm systems shall be designed so that the operator receives audible and visual indication of the out-of-limits conditions. Submitter Full Name: [ Not Specified ] Organization: [ Not Specified ] Submittal Date: Wed Jan 30 16:31:42 EST 2013 The committee incorporated the alarm functional requirement from to the fundamentals chapter. The requirement for audible alarm should be applied to all boiler and HRSG systems. Public Input No. 49-NFPA [New Section after ]

109 Page 100 of 595 First Revision No. 139-NFPA [ New Section after ] The audible alarm shall be permitted to be silenced by the operator after actuation, but the visual indication shall continue until the condition is within specified limits and has been reset. Submitter Full Name: [ Not Specified ] Organization: [ Not Specified ] Submittal Date: Wed Jan 30 16:33:22 EST 2013 The committee incorporated the alarm functional requirement from to fundamental chapter. The permissive to silence an audible alarm should apply to all boiler and HRSG systems. Public Input No. 50-NFPA [New Section after ]

110 Page 101 of 595 First Revision No. 140-NFPA [ New Section after ] Defeating of the alarm shall be authorized by a competent person and documented in accordance with operating procedures When it is necessary to manually defeat an alarm, defeating the alarm shall be performed by authorized personnel, and the alarm shall be tagged as inoperative. Submitter Full Name: [ Not Specified ] Organization: [ Not Specified ] Submittal Date: Wed Jan 30 16:39:14 EST 2013 The committee incorporated the alarm functional requirements from into the fundamentals chapter. The requirement that enable an alarm to be manual defeated ( ) should be applied to all boiler and HRSG systems. Public Input No. 52-NFPA [New Section after ]

111 Page 102 of 595 First Revision No. 230-NFPA [ Section No. 5.2 ] 5.2 Purpose. The purpose of this chapter shall be to establish minimum requirements for the design, installation, operation, and maintenance of single burner boilers, their fuelburning systems, and related systems to contribute to safe operation within design limits and, in particular, to the prevention of furnace explosions. Submitter Full Name: [ Not Specified ] Organization: [ Not Specified ] Submittal Date: Thu Mar 07 11:22:09 EST 2013 The revision is made to replace "safe operation" because it is unenforceable language. Public Input No. 222-NFPA [Section No. 5.2]

112 Page 103 of 595 First Revision No. 232-NFPA [ Section No ] * Two safety shutoff valves in series, each with a proof of closure switch, shall be provided in the fuel gas line to the main burner, and an automatic vent valve shall be provided between the two valves. When a listed automatic valve-proving system is used with two safety shutoff valves in series, each with a proof of closure switch, the automatic vent valve shall be permitted to be omitted When a listed automatic valve-proving system is used with two safety shutoff valves in series, each with a proof of closure switch, the automatic vent valve shall be permitted to be omitted * Valve proving Where automatic valve-proving systems are installed, valve proving shall be performed either after every burner shutdown or prior to every burner light-off. Submitter Full Name: [ Not Specified ] Organization: [ Not Specified ] Submittal Date: Thu Mar 07 12:05:58 EST 2013 The revision clarifies that the requirement to prove safety shutoff valves after every burner shutdown or prior to every burner light-off applies only to systems with automatic valve proving systems.

113 Page 104 of 595 First Revision No. 233-NFPA [ Section No ] Valve Leakage Test Permanent means shall be provided for making manual valve leakage tests of the main burner gas safety shutoff valves Valve Manual valve leakage tests of the main safety shutoff valves shall be conducted at least annually The use of an automatic valve-proving system shall not eliminate the annual leak test required in Submitter Full Name: [ Not Specified ] Organization: [ Not Specified ] Submittal Date: Thu Mar 07 12:21:51 EST 2013 All main fuel shutoff valves must be tested annually, regardless of the presence of an automatic valve-proving system.

114 Page 105 of 595 First Revision No. 231-NFPA [ Section No ] * Igniter Safety Shutoff Valves. Two safety shutoff valves in series shall be provided in the fuel gas line to the igniter, and an automatic vent valve shall be provided between the two valves. When a listed automatic valve-proving system is used with two safety shutoff valves in series, the automatic vent valve shall be permitted to be omitted When a listed automatic valve-proving system is used with two safety shutoff valves in series, the automatic vent valve shall be permitted to be omitted * Valve-proving Where an automatic valve-proving system is installed, valve -proving shall be performed either after every burner shutdown or prior to every burner light-off. Submitter Full Name: [ Not Specified ] Organization: [ Not Specified ] Submittal Date: Thu Mar 07 11:52:15 EST 2013 The revision clarifies that igniter safety shutoff valves are proven after every burner shutdown or prior to every burner light-off applies only where automatic valve proving systems are installed. The paragraph as previously written has been interpreted to mean that igniter safety shutoff valves require valve proving limit switches to be installed. That was not the intent of the committee. Public Input No. 204-NFPA [Section No ]

115 Page 106 of 595 First Revision No. 234-NFPA [ Section No ] Bypass The interlocks on the low water cutouts shall be permitted to be bypassed for blowdown purposes only design shall not require any deliberate defeating of an interlock to start or operate equipment The bypass of shall be of a type that is temporarily held during blowdown. Interlocks shall be permitted to be bypassed as allowed by (4), and (4) Interlocks Interlock devices shall not be bypassed manually at any time during normal operation. be permitted to be temporarily removed from service for maintenance or testing in accordance with the following: (1) Removal of the interlock shall be authorized by a competent person and documented in accordance with operating procedures. (2) Alternate means shall be substituted to supervise this interlock function in accordance with operating procedures Interlocks shall be permitted to be bypassed as allowed by , (4), and (4) The interlocks on the low water cutouts shall be permitted to be bypassed during normal operation for blowdown purposes only The bypass of shall be of a type that is temporarily held during blowdown. Submitter Full Name: [ Not Specified ] Organization: [ Not Specified ] Submittal Date: Thu Mar 07 13:07:27 EST 2013 The committee revised the text to allow interlocks to be bypassed for testing and maintenance where certain conditions are met. The revision addresses a need expressed by certain segments of the industry to have the capability to perform maintenance while the unit is on-line. This may become more important as NFPA 85 is applied to process and industrial boilers that are critical to an operation and must run continuously for long periods of time.

116 Page 107 of 595 Notes: Date Submitted By Apr 3, 2013 K. Ritchie changed lettered list to numbered list Public Input No. 99-NFPA [Section No ] Public Input No. 100-NFPA [Section No ]

117 Page 108 of 595 First Revision No. 235-NFPA [ Section No ] Starting Procedure. The following procedural steps shall be followed: (1) Shut off heavy oil to the system. (2) Insert the mechanical atomizer. (3) Bypass heavy oil and atomizing medium interlocks. [See (4).] (4) Open the light oil supply into the system. (5) Follow prefiring and light-off cycles described in Section 5.5. (6) Set combustion control at the light-off rate. (7) When steam pressure has reached the point required for heating and atomizing the heavy oil, shut down in accordance with the normal shutdown procedure as described in Section 5.5. (8) Shut off the light oil supply to the system. (9) Remove the mechanical atomizer. (10) Insert the steam atomizer. (11) Make the heavy oil and atomizing medium interlocks operable by removing bypasses. (12) Open the heavy oil supply to the system. (13) Continue the boiler start-up sequence. Submitter Full Name: [ Not Specified ] Organization: [ Not Specified ] Submittal Date: Thu Mar 07 13:46:29 EST 2013 The revision clarifies which steps refer to light oil and which apply to heavy oil. Public Input No. 118-NFPA [Section No ] Public Input No. 119-NFPA [Section No ]

118 Page 109 of 595 First Revision No. 238-NFPA [ Section No ] Supervised Manual Supervised Burner Management Systems for Oil-Fired Watertube Boilers For oil-fired watertube boilers, the steps listed in Table (a) through Table (d) shall be taken by a trained operator when starting a manual supervised manual unit, and the indicated interlocks shall be satisfied at each step. Table (a) Oil-Fired Watertube Boilers: Prefiring Cycle Operator Actions * Interlock Functions (1) Check that fuel safety or supervisory shutoff (1) Fuel safety or supervisory shutoff valve is closed. valve is closed. (2) Start fan. (2) Fan is on. (3) Where used, open (3) Atomizing medium supply is available. atomizing medium valve. (4) Open damper(s) to purge position. (5) Start purge timer. (5) Purge is complete. (6) Place damper and fuel control valve in light-off position. (7) None. (4) (a) Air pressure and open damper(s) or (b) airflow. [See (9) and (10).] (6) Damper and fuel control valve are in light-off position. If light-off airflow is less than purge airflow rate, start light-off time limit timer. (7) Spark, igniter, and main safety shutoff valves are ready for operation. * In listed order. Table (b) Oil-Fired Watertube Boilers: Light-Off Cycle

119 Page 110 of 595 Operator Actions * Interlock Functions (1) Energize ignition transformer and igniter safety shutoff valves. (2) Open fuel safety shutoff valve to main burner. (3) Close recirculating valve, where used. (4) Open manual fuel shutoff valve. (5) Bring unit to present operating pressure at rate specified by manufacturer, maintaining air-fuel ratios as established by tests. (6) On reaching preset pressure range, change to automatic combustion control. (1) Prove igniter flame within 10 seconds of energization of igniter fuel valves. (For Class 3 special igniter, proof of igniter operation is not required.) (2) None. (3) None. (4) Prove main flame within 10 seconds for Nos. 2 and 4 oils or 15 seconds for Nos. 5 and 6 oils. Close igniter safety shutoff valve(s). (5) None. (6) None. * In listed order. Table (c) Oil-Fired Watertube Boilers: Normal Shutdown Cycle Operator Actions * Interlock Functions (1) Fuel safety shutoff (1) Shut off fuel supply to main burner. valve(s) to main burner is closed. (2) Open fuel recirculating valve, where used. (2) None. (3) Shut off atomizing medium, where used. (3) None. (4) Remove fuel atomizer. (4) None. (5) Perform postpurge of furnace and boiler gas passes. Duration of postpurge must be no less than 15 seconds (5) None. at airflow rate not exceeding that at which unit was shut down. (6) After postpurge, fan can be permitted to be shut down. (6) None. * In listed order. Table (d) Oil-Fired Watertube Boilers: Safety Shutdown Cycle (1) None. Operator Actions * (2) Perform postpurge of furnace and boiler gas passes. Duration of postpurge must be no less than 15 seconds at airflow rate not exceeding that at which unit was shut down. (3) After postpurge, fan can be permitted to be shut down. Interlock Functions (1) Shut off fuel supply to main burner; shut off fuel supply and interrupt spark to igniter, if in operation. (2) None. (3) None.

120 Page 111 of 595 * In listed order Fuel pressure and temperature, atomizing medium, control system energy, power, and water level shall have been established When interlocks have been satisfied, this fact shall be indicated to the operator The fuel to be fired shall be selected The alternate fuel system shall be placed in a nonfiring condition The supervisory or safety shutoff valve(s) shall be closed An igniter as specified in shall be provided * Any of the following conditions shall accomplish a safety shutdown, and the burner shall not be restarted until a trained operator goes out to the boiler, determines the cause of the shutdown, and takes the necessary corrective action to ensure that conditions are within specified operating limits prior to restarting: (1) Low pressure in the fuel supply (2) Loss of combustion air supply (3) Loss or failure to establish flame (4) Loss of control system actuating energy (5) Power failure (6) Low water level as determined by the auxiliary low water cutout (7) Loss of atomizing medium (8) Excessive steam pressure or water temperature Where oil heating is provided, either of the following conditions shall cause alarms to sound: (1) Low oil temperature (2) High oil temperature Submitter Full Name: [ Not Specified ] Organization: [ Not Specified ] Submittal Date: Thu Mar 07 14:25:57 EST 2013

121 Page 112 of 595 The title is revised to be consistent with the defined term. The SBB committee requests that the Fundamentals committee reinstate the definition in chapter 3.

122 Page 113 of 595 First Revision No. 239-NFPA [ Section No ] Supervised Manual Supervised Burner Management Systems for Gas-Fired Watertube Boilers For gas-fired watertube boilers, the steps listed in Table (a) through Table (d) shall be taken by a trained operator when starting a supervised manual supervised unit, and the indicated interlocks shall be satisfied at each step. Table (a) Gas-Fired Watertube Boilers: Prefiring Cycle Operator Actions * Interlock Functions (1) Check that gas safety (1) Gas safety shutoff valves are closed. shutoff valves are closed. (2) Start fan. (2) Fan motor is on. (3) Open damper(s) to purge position. (4) Start purge timer. (4) Purge is complete. (5) Place damper and gas control valve in lightoff position. (6) None. (3) (a) Air pressure and open damper(s) or (b) airflow. [See (9) and (10).] (5) Damper and fuel control valve are in light-off position. If light-off airflow is less than purge airflow rate, start light-off time limit timer. (6) Spark and igniter and main safety shutoff valves are ready for operation. * In listed order. Table (b) Gas-Fired Watertube Boilers: Light-Off Cycle Operator Actions * (1) Energize ignition transformer and igniter safety shutoff valve(s). (2) Open gas safety shutoff valves to main burner. (3) Bring unit to preset operating pressure at rate specified by manufacturer, maintaining air-fuel ratios as established by tests. (4) On reaching preset range, change to automatic combustion control. Interlock Functions (1) Prove igniter flame within 10 seconds of the energization of igniter fuel valves. (For Class 3 special igniter, proof of igniter operation is not required.) (2) Prove main flame is within 10 seconds. Close igniter safety shutoff valve(s). (3) None. (4) None. * In listed order. Table (c) Gas-Fired Watertube Boilers: Normal Shutdown Cycle

123 Page 114 of 595 Operator Actions * Interlock Functions (1) Shut off gas supply to main burner and to igniter, if in (1) None. operation, and interrupt spark. (2) Perform postpurge of furnace and boiler gas passes. Duration of postpurge must be no less than 15 seconds at airflow rate not (2) None. exceeding that at which unit was shut down. (3) After postpurge, fan can be permitted to be shut down. (3) None. * In listed order. Table (d) Gas-Fired Watertube Boilers: Safety Shutdown Cycle Operator Actions * Interlock Functions (1) Shut off gas supply to main burner, shut off fuel supply, and interrupt spark (1) None. to igniter, if in operation. Where used, simultaneously energize inerting system. (2) Perform postpurge of furnace and boiler gas passes. Duration of postpurge must be no less than 15 seconds at an (2) None. airflow rate not exceeding that at which unit was shut down. (3) After postpurge, fan can be permitted to be shut down. (3) None. * In listed order Control system energy, power, and water level shall have been established When interlocks have been satisfied, this fact shall be indicated to the operator The fuel to be fired shall be selected The alternate fuel system shall be placed in a nonfiring condition The supervisory or safety shutoff valve(s) shall be closed An igniter as specified in shall be provided Any of the following conditions shall accomplish a safety shutdown, and the burner shall not be restarted until a trained operator goes out to the boiler, determines the cause of the shutdown, and takes the necessary corrective action to ensure that conditions are within specified operating limits prior to restarting: (1) High gas pressure (2) Low gas pressure (3) Loss of combustion air supply (4) Loss of or failure to establish flame (5) Loss of control systems actuating energy

124 Page 115 of 595 (6) Power failure (7) Low water level as determined by the auxiliary low water cutout (8) Excessive steam pressure or water temperature Submitter Full Name: [ Not Specified ] Organization: [ Not Specified ] Submittal Date: Thu Mar 07 14:28:13 EST 2013 The title is revised to be consistent with the defined term. The SBB committee requests that the Fundamentals committee reinstate the definition in chapter 3.

125 Page 116 of 595 First Revision No. 236-NFPA [ Section No ] Required Equipment. The following equipment shall be required: (1) A burner that is capable of firing the two fuels simultaneously during the transfer period (2) A combustion control system that is capable of performing the following functions: (a) (b) (c) (d) (e) Proportioning fuel flow for each fuel individually Limiting total fuel input to the maximum capacity of the boiler Controlling a minimum airflow rate Controlling minimum input rates of each fuel Providing a stable return to design air-fuel ratio after the trip or shutdown of either fuel (3) A fuel transfer mode that includes the following: (a) (b) (c) (d) A gas-firing mode in which oil cannot be fired An oil-firing mode in which gas cannot be fired A gas-oil-firing mode that permits simultaneous firing of both fuels, provided all interlocks for both fuels are satisfied, including light-off position for both fuel valves A control device, transfer timer, and an alarm for 5.7.2(3)(c), to limit continuous operation in this mode (4) A safety interlock system with the following capabilities: (a) (b) (c) (d) (e) (f) (g) (h) Meets the requirements of for each fuel being fired Provides, on an interlock action peculiar to only one of the fuels an independent interlock to each fuel being fired, that this particular fuel automatically shuts down the affected fuel with operation continuing on the unaffected fuel in a stable manner; shutdown of both fuels is permitted Provides that both the first and second fuels be introduced with their flow control valves in light-off positions Provides an interlock action that will trip either fuel should its respective flow control valve leave a predetermined setting during fuel transfer Provides for the introduction of the second fuel without requiring a boiler purge Requires a manual reset following any interlock shutdown Prohibits the simultaneous light-off of both fuels Provides detector(s) to supervise any of the following conditions: i. Igniter flame as permitted by igniter class ii. Gas firing iii. Oil firing

126 Page 117 of 595 iv. Combined gas and oil firing (i) Burner flame detectors shall be permitted to supervise multiple fuels. Submitter Full Name: [ Not Specified ] Organization: [ Not Specified ] Submittal Date: Thu Mar 07 13:51:03 EST 2013 Notes: Date Submitted By Apr 3, 2013 The text is revised editorially so that the requirement is easier to interpret. K. Ritchie 5.7.2(4)b - Unclear as currently written: is there a word missing between 'manner' and 'shutdown'? Perhaps replace the semicolon with the word 'until'? Public Input No. 9-NFPA [Section No ]

127 Page 118 of 595 First Revision No. 155-NFPA [ Section No ] This chapter shall not eliminate the need for competent engineering judgment. Submitter Full Name: [ Not Specified ] Organization: [ Not Specified ] Submittal Date: Tue Feb 26 11:36:28 EST 2013 The principal requirement of subsection is redundant to subsection Paragraphs and state the designer has the latitude and responsibility for demonstrating and documenting the validity of the proposed design. These requirements provide a more enforceable language than the requirements of a competent judgment Public Input No. 42-NFPA [Section No ]

128 Page 119 of 595 First Revision No. 156-NFPA [ Section No ] 6.4.1* Unattended and Off-Site Operation. Unattended operation, no operator at the operating location(s), or operation of the plant from an off-site operating location shall require a higher level of automation, safety interlocks, and reliability, which are not addressed in this code In addition to operational and safety analysis, designs for off-site and unattended operations shall include risk analysis and hazard studies and shall be approved by the authority having jurisdiction Jurisdictional requirements regarding operator attendance shall be met. Submitter Full Name: [ Not Specified ] Organization: [ Not Specified ] Submittal Date: Tue Feb 26 12:23:54 EST 2013 The Fundamentals committee adopted similar language in FR 85 for a new section following The committee did not relocate the annex text because "larger units" does not provide instructive guidance for other types of equipment. Public Input No. 72-NFPA [Section No ]

129 Page 120 of 595 First Revision No. 157-NFPA [ Section No ] General The basic requirements of an interlock system for a unit shall accomplish the following: (1) Protect personnel from injury (2) Protect equipment from damage (3) Protect boiler operation by limiting actions to a prescribed operating sequence or by initiating trip devices when approaching an out-ofrange or unstable operating condition The interlock system shall comply with Section * The mandatory automatic trips specified in shall be provided Additional automatic trips shall be permitted. (See for trip function evaluation requirements.) Fuel-specific interlocks shall be provided for each design basis fuel * Operating personnel shall be made aware of the limitations of the interlock system. Submitter Full Name: [ Not Specified ] Organization: [ Not Specified ] Submittal Date: Tue Feb 26 12:33:30 EST 2013 The Fundamentals committee added similar text to 4.11 in FR 142. Therefore, can be deleted because it is redundant to Public Input No. 47-NFPA [Section No ]

130 Page 121 of 595 First Revision No. 172-NFPA [ Section No ] The mandatory master fuel trip sensing elements and circuits shall be independent of all other control elements and circuits. Exception No. 1: Individual burner flame detectors also shall be permitted to be used for initiating master fuel trip systems. Exception No. 2: Airflow measurement, auctioneered furnace draft, and drum water level, and feedwater flow signals from the boiler control system shall be permitted to be used for a master fuel trip, provided all the following conditions are met: (1) These interlocks are hardwired into the burner management system. (2) Tripping set points are protected from unauthorized changes. (3) Any single component failure of these sensing elements and circuits does not prevent a mandatory master fuel trip. Submitter Full Name: [ Not Specified ] Organization: [ Not Specified ] Submittal Date: Tue Feb 26 17:48:20 EST 2013 The committee revised exception number 2 to be consistent with revisions to Figure and table (a).

131 Page 122 of 595 First Revision No. 160-NFPA [ Section No ] * Interlock System. Figure and Table (a) through Table (c) show the minimum required system of interlocks that shall be provided for basic furnace protection for a multiple burner boiler operated in accordance with this code. Figure Interlock System for Multiple Burner Boiler. Table (a) Interlock System for Multiple Burner Boiler

132 Page 123 of 595 Block Number Block 1 Block 2a1 Block 2a2 Block 2b Blocks 3 through 13 Block 3 Block 4 Action Loss of an individual igniter flame shall cause the following actions: (1) Close the individual igniter safety shutoff valve(s) and de-energize the spark(s). (2) Open the vent valve (fuel gas ignition only). (3) Signal the main flame protection system that the igniter flame has been lost. High or low igniter fuel gas header pressure shall be interlocked to initiate the tripping of the igniter header and individual igniter safety shutoff valves and deenergize sparks. Low igniter fuel oil header pressure shall be interlocked to initiate the tripping of the igniter header and individual igniter safety shutoff valves and deenergize sparks. Where fuel oil is used for ignition fuel with air or steam atomization, atomizing air or steam pressure out of range shall trip the igniter and individual igniter safety shutoff valves and de-energize sparks. Where direct electric igniters are used, blocks 1 and 2 shall not apply. However, the master fuel trip system shall de-energize sparks and prevent re-energizing until all conditions for light-off have been reestablished. These blocks represent conditions that initiate the tripping of all main and ignition fuel supplies through a master fuel trip relay contact(s). The master fuel trip relay(s) shall be of the type that stays tripped until the unit purge system interlock permits it to be reset. Whenever the master fuel trip relay(s) is operated, it shall trip all fuel header, burner, and igniter safety shutoff valves and de-energize all sparks and all ignition devices within the unit and flue gas path through master fuel trip relay contact(s). Master fuel trip relay contacts shall also trip the fuel oil system circulating and recirculating valves. If the design of the fuel oil supply system is such that backflow of fuel oil through the recirculating valve is inherently impossible or positively prevented, this valve shall be permitted to be manually operated and shall not be required to be interlocked to close automatically on a master fuel trip. The master fuel trip relay contacts shall also trip primary air fans or exhausters, coal feeders, pulverizers, and coal burner line shutoff valves, or take equivalent functional action to stop coal delivery to burners. The master fuel trip logic shall trip all fuel gas path auxiliary systems that introduce hazards through the addition of fuel, oxidizing agents, or ignition sources. The loss of all induced draft fans shall activate the master fuel trip relay. The loss of all forced draft fans shall activate the master fuel trip relay.

133 Page 124 of 595 Block Number Block 5 Block 6(See A ) Block 7 Block 8 (See A A ) Block 9 (See A A ) Block 10a (See A A ) Block 10b (See A ) Block 11 Block 12 Block 13a Block 13b Block 13c Block 13d Action Low combustion airflow below the permitted limits shall activate the master fuel trip relay. High positive furnace pressure, such as that resulting from a tube rupture or damper failure, shall activate the master fuel trip relay. High negative furnace pressure shall activate the master fuel trip relay. Loss of all flame in the furnace shall activate the master fuel trip relay. A partial loss of flame that results in a hazardous condition shall activate the master fuel trip relay. When all fuel inputs to the furnace are shut off following a shutdown of the boiler for any reason, the master fuel trip relay shall be activated in accordance with Table (b) or Table (c). For drum-type boilers, a low drum water level shall activate the master fuel trip relay. For once-through boilers, water flow below the minimum specified by the manufacturer shall activate the master fuel trip relay. A manual switch that actuates the master fuel trip relay directly shall be provided for use by the operator in an emergency. The igniter fuel trip shall activate the master fuel trip relay in accordance with Table (b) or Table (c), if igniter fuel is the only fuel in service or if it is being used to stabilize a main fuel. When the fuel gas burner header fuel pressure is above the maximum or below the minimum for a stable flame, that fuel shall be tripped. If fuel gas is the only fuel in service, the master fuel trip relay shall be actuated. When the fuel oil burner header fuel pressure is below the minimum for a stable flame, that fuel shall be tripped. If fuel oil is the only fuel in service, the master fuel trip relay shall be actuated. This block represents operation of the fuel oil trip to prevent operation when atomizing air or steam pressure is out of range. If fuel oil is the only fuel in service, the master fuel trip relay shall be actuated. This block represents the tripping/shutdown of coalfiring equipment that will cause a coal fuel trip. If coal is the only fuel in service, the master fuel trip relay shall be actuated.

134 Page 125 of 595 Block Number Block 14a Block 14b Action Loss of flame at an individual fuel gas or fuel oil burner with one or more additional burners operating with stable flames that does not introduce a serious enough condition to warrant a master fuel trip as called for in block 8 shall close the individual burner safety shutoff valve(s) and associated igniter safety shutoff valve(s) and de-energize the associated igniter spark. For gang-operated burner valves, the requirements of (B)(19) and (B) (19) shall be met. On loss of main coal burner flame, the tripping strategies of shall be followed. Table (b) Fuel Inputs Shutoff When Class 1 Igniters Are Used Condition (1) First Class 1 igniter(s) fails to light after successful unit purge. [See (B)(9), (B)(10), and (B)(7).] (2) Any igniters proven on, all other fuel sources off, all igniter valves subsequently closed. (3) Any Class 1 igniter(s) proven on, any burner valve leaves closed limit, all burner valves subsequently closed, no other main fuel in service, igniter(s) remain proven. Action Required (1) Igniter valve(s) shall be closed immediately. Master fuel trip not required, but a 1-minute delay shall be required before retrial of that or any other igniter. (2) Master fuel trip shall be actuated. (3) Associated main fuel gas trip valve and/or fuel oil trip valve shall be closed (fuel gas trip and/or fuel oil trip), proven igniters shall be permitted to remain in service. (4) Any Class 1 igniter(s) proven on, any pulverizer startup initiated, all pulverizers (4) Proven igniters shall be permitted to subsequently stopped, no other main fuel remain in service. in service, igniter(s) remain proven. (5) All igniter and burner valves closed (5) Master fuel trip shall be actuated. and all feeders or pulverizers stopped. Table (c) Fuel Inputs Shutoff When Class 2 or Class 3 Igniters Are Used

135 Page 126 of 595 Condition (1) First Class 2 or 3 igniter(s) fails to light after successful unit purge. [See (B)(9), (B)(10), and (B)(7).] (2) Any igniters proven on, all other fuel sources off, all igniter valves subsequently closed. (3a.1) Class 2 igniter(s) proven on, first main burner trial for ignition fails. (3a.2) Class 2 igniter(s) proven on, last main burner is taken out of service in a normal shutdown. (3a.3) Class 2 igniter(s) proven on, last main burner is taken out of service in an abnormal shutdown. (3b.1) Class 3 igniters proven on, first main burner trial for ignition fails. (3b.2) Class 3 igniter(s) proven on, last main burner is taken out of service in a normal shutdown. (3b.3) Class 3 igniter(s) proven on, last main burner is taken out of service in an abnormal shutdown. (4) Any Class 2 igniter(s) proven on, any pulverizer startup initiated, all pulverizers subsequently stopped, no other main fuel in service, igniter(s) remain proven. (5) All igniter and burner valves closed and all feeders or pulverizers stopped. Action Required (1) Igniter valve(s) shall be closed immediately. Master fuel trip not required, but a 1-minute delay shall be required before retrial of that or any other igniter. (2) Master fuel trip shall be actuated. (3a.1) Master fuel trip shall be actuated. (3a.2) Associated main fuel gas trip valve and/or fuel oil trip valve shall be closed (fuel gas trip and/or fuel oil trip), proven igniters shall be permitted to remain in service. (3a.3) Master fuel trip shall be actuated. (3b.1) Master fuel trip shall be actuated. (3b.2) Master fuel trip shall be actuated. (3b.3) Master fuel trip shall be actuated. (4) (a) If first pulverizer fails to ignite as described in (B)(12), master fuel trip shall be actuated. (b) If last pulverizer in service is tripped, master fuel trip shall be actuated. (c) If last pulverizer in service is taken out of service in a normal shutdown sequence by an operator, proven igniters shall be permitted to remain in service. (5) Master fuel trip shall be actuated. Supplemental Information File Name Description NFPA85_Fig_6_4_2_3_1.pdf Revised Figure Submitter Full Name: [ Not Specified ] Organization: [ Not Specified ] Submittal Date: Tue Feb 26 13:49:44 EST 2013

136 85 44 BOILER AND COMBUSTION SYSTEMS HAZARDS CODE 1 Loss of igniter flame Typical cause of trip indication Close individual igniter safety shutoff valve(s) and de-energize sparks 2a1 Igniter fuel gas pressure out of stable range Igniter fuel gas trip Igniter fuel trip for Class 1 igniters, block 11 2a2 2b Igniter fuel oil pressure out of stable range Igniter atomizing medium pressure improper Igniter fuel oil trip Close igniter header and individual igniter safety shutoff valves and de-energize sparks 3 Loss of ID fan(s) 4 Loss of FD fan(s) 5 Combustion airflow low High positive or high negative furnace pressure Loss of all flame Partial loss of flame, introducing hazard Master fuel trip logic Master fuel trip relay(s) Trip all flue gas path auxiliary systems that introduce hazards through addition of fuel, oxidizing agents, or ignition sources. (See ) 9 All fuel inputs shut off 10a Low drum water level 11 Manual trip switch 12 Igniter fuel trip (Class 1 igniters) A N D 13a Burner gas header fuel pressure high or low Gas fuel trip logic Close main gas safety shutoff valve(s) and individual burner safety shutoff valves 13b 13c Low main oil burner pressure Atomizing medium pressure improper Oil fuel trip logic Close main oil safety shutoff valve(s) and individual burner safety shutoff valves 13d 14a 14b All coal-firing equipment stopped or tripped or common coal-firing equipment tripped Loss of individual gas or oil burner flame with one or more additional stable burner flames present Loss of main coal burner flame Coal fuel trip logic Close individual burner safety shutoff valve(s) and individual igniter safety shutoff valve(s) and de-energize associated sparks Follow tripping strategy in Stop coal flow to pulverizers and burners FIGURE Interlock System for Multiple Burner Boiler Edition

137 Page 127 of 595 For once-through boilers, it's critical to initiate MFT on low feedwater flow as defined by the boiler manufacturer to protect the boiler "Low furnace pressure" is just as critical as "high furnace pressure" to protect the furnace, The igniter fuel trip is block 12, not block 11. Therefore the committee made the editorial correction and requested staff issue an erratum on the current edition. Public Input No. 79-NFPA [Section No ] Public Input No. 96-NFPA [Section No ] Public Input No. 97-NFPA [Section No ] Public Input No. 146-NFPA [Section No ]

138 Page 128 of 595 First Revision No. 164-NFPA [ Section No (C) ] (C)* All Fan Trip. (1) On an emergency shutdown where no fans remain in service, no action shall be taken other than damper actions necessary to prevent positive or negative furnace pressure transients beyond design limits. (2) The flue gas recirculation system shall be operated as recommended by the boiler manufacturer. (3) Except as noted in (C)(4), once Once the FD and ID fan(s) have stopped, slowly open all dampers in the air and flue gas passages to the full open position. (4) * When the flue gas flow path is combined with the flue gas flow path(s) of other operating boilers, it shall be permitted to isolate the flue gas path for the tripped unit once the ID and FD fan(s) have stopped. (5) This condition The conditions in (C)(3) or (C)(4) shall be maintained for an all fan trip hold period of at least 15 minutes prior to allowing any ID or FD fan to be restarted. (6) At the end of this 15 minute period, the fan(s) shall be started in accordance with Section 6.5. (7) The airflow shall be increased gradually to the purge rate, and a boiler enclosure purge shall be completed. Submitter Full Name: [ Not Specified ] Organization: [ Not Specified ] Submittal Date: Tue Feb 26 16:14:59 EST 2013 Paragraph (C) is modified in support of boilers with combined flue gas paths as provided in A new (2) is added to specify that flue gas recirculation systems should be operated in accordance with the boiler manufacturer's instructions. Notes: Date Submitted By Apr 3, K. Ritchie (C)(2) - inserted 'The' before 'flue' 2013 Apr 3, 2013 K. Ritchie (C)(3) - this entry should be rephrased using 'shall' Public Input No. 110-NFPA [Section No (C)]

139 Page 129 of 595 First Revision No. 166-NFPA [ Section No (D) ] (D) After completion of the boiler enclosure purge, one of the unit following actions shall be permitted to either : (1)* Shut down, closing the burner air registers and shutting down the FD and ID fans; however, maintaining airflow through the unit to prevent accumulation of combustible gases is a prudent procedural step due to the potential of fuel leak-by and open all dampers to allow an open flow path through the boiler enclosure. (2)* Shut down the FD and ID fans and close dampers in the boiler flue gas path. (3) Relight in accordance with 6.6.5, 6.7.5, or 6.8.5, as applicable, depending on the fuels being fired. Submitter Full Name: [ Not Specified ] Organization: [ Not Specified ] Submittal Date: Tue Feb 26 16:46:59 EST 2013 Notes: Date Apr 8, 2013 Apr 8, 2013 The revision addresses the industry practice of "bottling a boiler" to prevent heat loss. Submitted By K. Ritchie (D)(1): Inserted asterisk to indicate there is explanatory text in Annex A. [ Not Specified ] (D)(2) - Inserted asterisk to indicate there is explanatory text in Annex A. Public Input No. 107-NFPA [Section No (D)]

140 Page 130 of 595 First Revision No. 170-NFPA [ Section No ] * Where an interlock system is provided to start, stop, and trip ID fans and FD fans in pairs, the associated FD fan shall be tripped on loss of an individual ID all ID fans paired to that FD fan, and the dampers associated with both those fans shall be closed, provided they are not the last fans in service. If they are the last fans in service, the dampers associated with both those fans shall remain open. Submitter Full Name: [ Not Specified ] Organization: [ Not Specified ] Submittal Date: Tue Feb 26 17:30:04 EST 2013 Larger units typically have four ID fans and two FD fans and, if fan pairing is required, the pairing is usually such that each pair consists of two ID fans paired to one FD fan. It is not necessary to trip the FD fan if one of the ID fans in the pair remains running. This section has been interpreted to require that an FD fan be tripped anytime either of the associated ID fans is not running and that is not believed to be the intent of this Code. Public Input No. 82-NFPA [Section No ]

141 Page 131 of 595 First Revision No. 174-NFPA [ Section No ] On loss of all ID fans, all FD fans shall be tripped. All ID fan dampers shall be opened after a time delay to minimize high draft during fan coastdown. Dampers shall remain open and fans shall be started in accordance with through Flue gas recirculation fan system dampers shall be closed. (A) The procedure of (C) shall be followed. (B)* A time delay before tripping of FD fan(s) shall be permitted where the duration is determined by a transient pressure analysis. Submitter Full Name: [ Not Specified ] Organization: [ Not Specified ] Submittal Date: Wed Feb 27 09:40:48 EST 2013 Section is in conflict with the Section (C). The All Fan trip sections were revised last cycle. The change to Section will make the two sections work together. Tripping of ID fans creates a mandatory MFT, and the subsequent flame collapse, along with a decrease of incoming air created by loss of FD fans can create an excessive furnace negative pressure excursion. Maintaining an incoming airflow for a short duration may minimize the magnitude of the negative pressure excursion. Public Input No. 86-NFPA [Section No ] Public Input No. 28-NFPA [Section No ] Public Input No. 39-NFPA [Section No ] Public Input No. 94-NFPA [New Section after ]

142 Page 132 of 595 First Revision No. 176-NFPA [ Section No ] * The master fuel trip (not necessarily automatic) shall be activated when the furnace negative pressure exceeds the value recommended by the manufacturer. If fans are operating after the trip, they shall be continued in service. The airflow shall not be increased by deliberate manual or automatic control actions. Submitter Full Name: [ Not Specified ] Organization: [ Not Specified ] Submittal Date: Wed Feb 27 11:12:24 EST 2013 The paragraph is redundant to (B). In addition, high negative furnace pressure is now an automatic MFT specified in FR 160.

143 Page 133 of 595 First Revision No. 179-NFPA [ Section No ] Before the main fuel firing and following a master fuel trip, all ID fans shall be tripped if furnace negative pressure exceeds the value recommended by the manufacturer. A short time delay shall be permitted to allow for the negative pressure transients due to loss of the main flame. The value of the negative pressure at which this trip is activated shall be greater than that specified in more negative than the value used to initiate a master fuel trip. Submitter Full Name: [ Not Specified ] Organization: [ Not Specified ] Submittal Date: Wed Feb 27 11:36:55 EST 2013 Notes: Date Submitted By Apr 3, 2013 The term "greater" is not specific, especially when referring to negative values. In addition, the cross-reference is no longer valid and is therefore replaced with appropriate language. K. Ritchie replaced 'MFT' with 'master fuel trip' to match style of rest of code Public Input No. 33-NFPA [Section No ] Public Input No. 95-NFPA [Section No ]

144 Page 134 of 595 First Revision No. 180-NFPA [ Section No ] Where an interlock system is provided to start, stop, and trip ID fans and FD fans in pairs, the associated ID fan fans paired to a particular FD fan shall be tripped on loss of an individual that FD fan, and the dampers associated with both those fans shall be closed, provided they are not the last fans in service. If they are the last ID fans in service, one of the ID fan fans shall remain in controlled operation, and the dampers associated with the FD fan shall remain open. Submitter Full Name: [ Not Specified ] Organization: [ Not Specified ] Submittal Date: Wed Feb 27 11:45:27 EST 2013 Larger units typically have four ID fans and two FD fans and, if fan pairing is required, the pairing is usually such that each pair consists of two ID fans paired to one FD fan. The text needs to be modified to identify the fact that multiple ID fans may need to be tripped on the loss of an FD fan rather than a singular ID fan. Public Input No. 83-NFPA [Section No ]

145 Page 135 of 595 First Revision No. 181-NFPA [ Section No ] On loss of all FD fans, all opened FD fan dampers shall be opened after a time delay to minimize high duct pressure during fan coastdown. Dampers shall remain open. Flue The flue gas recirculation fan system dampers shall be closed operated in accordance with the boiler manufacturer's instructions. After FD fan coastdown, all FD fan dampers shall be opened fully.. Submitter Full Name: [ Not Specified ] Organization: [ Not Specified ] Submittal Date: Wed Feb 27 12:06:00 EST 2013 The statement relating to flue gas recirculation system was reordered for clarity. The boiler manufacturer's instructions for operating or tripping the flue gas recirculation system should be followed. In addition, unenforceable language was removed. Public Input No. 29-NFPA [Section No ]

146 Page 136 of 595 First Revision No. 182-NFPA [ Section No ] Functional Requirements * Alarms shall be used to indicate equipment malfunction, hazardous conditions, and misoperation. For the purpose of this code, the primary concern shall be alarms that indicate conditions that pose a threat of impending or immediate hazards Alarm systems shall be designed so that, for the required alarms in , the operator receives audible and visual indication of the out-oflimits condition Means shall be permitted to silence the audible alarm after actuation, but the visual indication shall continue until the condition is within acceptable limits Where equipment malfunction makes it necessary to manually defeat an alarm, it shall be performed by authorized personnel, and the alarm shall be tagged as inoperative. Submitter Full Name: [ Not Specified ] Organization: [ Not Specified ] Submittal Date: Wed Feb 27 12:41:50 EST 2013 The Fundamentals committee incorporated this text into FRs 138, 139 and 140. Therefore, it is deleted from chapter 6 because it is redundant to chapter 4. Public Input No. 48-NFPA [Section No ]

147 Page 137 of 595 First Revision No. 21-NFPA [ Section No ] Axial Flow Fan Nearing Stall Line. This condition shall be sensed and alarmed in accordance with the manufactuer's recommendations. Submitter Full Name: Kimberly Shea Organization: National Fire Protection Assoc Submittal Date: Fri Jan 11 12:08:42 EST 2013 The committee added a requirement for editorial consistency with other subparagraphs in this section.

148 Page 138 of 595 First Revision No. 22-NFPA [ Section No ] Reburn Fuel Oil Supply Pressure Low. This alarm shall apply to units with a reburn system. Submitter Full Name: Kimberly Shea Organization: National Fire Protection Assoc Submittal Date: Fri Jan 11 12:09:57 EST 2013 The committee added a requirement for editorial consistency with other sub-paragraphs in this section.

149 Page 139 of 595 First Revision No. 184-NFPA [ Section No ] The furnace pressure control system, as shown in Figure , shall include the following features and functions: (1) Three furnace pressure transmitters (A) in an auctioneered medianselect system, each on a separate pressure-sensing tap and with suitable monitoring (B) to minimize the possibility of operating with a faulty furnace pressure measurement (2) A feed-forward signal (C) to the furnace pressure control subsystem (D), representative which is a function of boiler airflow demand, which can be permitted to be a fuel flow signal, airflow control equipment demand signal, or other index of demand, but not and is not based on a measured airflow signal (3) The furnace pressure control subsystem (D), which positions the furnace pressure regulating equipment so as to maintain furnace pressure at the desired set point (4) * The furnace pressure control protection subsystem (G), which is applied after the auto/manual transfer station (E) to minimize furnace pressure excursions under both auto and manual operation modes and which includes a feed-forward override action (F) initiated by a master fuel trip in anticipation of a furnace pressure excursion due to flame collapse and works in conjunction with logic that minimizes furnace pressure excursions (5) Axial fans, where used, operated in their stable range to prevent uncontrollable changes in airflow or flue gas flow Figure Furnace Pressure Control Systems Requirements.

150 Page 140 of 595 Submitter Full Name: [ Not Specified ] Organization: [ Not Specified ] Submittal Date: Wed Feb 27 14:46:47 EST 2013 Upon receipt of the Master Fuel Trip (MFT) signal, fuel flow will go to zero very quickly. The disappearance of the fuel flow-based feedforward signal could create additional challenges for the furnace pressure control. The feedforward signal is derived from the representative of boiler airflow demand to predict or relate the furnace pressure regulating control element (H) position, usually through the use of a function generator or F(X). Public Input No. 3-NFPA [Section No ]

151 Page 141 of 595 First Revision No. 163-NFPA [ Section No ] An Except as noted in , an open-flow air path from the inlet of the FD fans through the stack shall be ensured under all operating conditions. Submitter Full Name: [ Not Specified ] Organization: [ Not Specified ] Submittal Date: Tue Feb 26 15:56:05 EST 2013 The language recognizes that a new was added specifically for multiple units with combined flue gas paths. Public Input No. 69-NFPA [Section No ]

152 Page 142 of 595 First Revision No. 162-NFPA [ New Section after ] When the flue gas flow path is combined with the flue gas flow paths of other boilers, the following requirements shall be met: (1) An open-flow air path from the inlet of the FD fans through the stack shall be ensured at any time the FD or ID fans for that unit are in operation. (2) When the fans on an idle unit are off, a means shall be provided to prevent flow of the flue gas from an operating unit to an idle unit(s). (3) When starting an idle unit, procedures shall be established to prevent backflow of flue gas from an operating unit to an idle unit. (4) Once an open-flow air path has been established, the unit startup shall be permitted as described in and 6.6.5, 6.7.5, or Submitter Full Name: [ Not Specified ] Organization: [ Not Specified ] Submittal Date: Tue Feb 26 15:39:42 EST 2013 Notes: Date Submitted By Feb 26, 2013 It is becoming more common to combine multiple flue gas paths to reach an economy of scale for additional flue gas cleaning equipment. There is concern about the possibility of such designs being under positive pressure at the point the flue gas paths are combined. The possibility of flue gas flow into an idle unit is a concern. [ Not Specified ] NOTE - this should have been entered as a new paragraph after (new ). Subsequent paragraphs should be renumbered. Public Input No. 104-NFPA [New Section after ]

153 Page 143 of 595 First Revision No. 185-NFPA [ Section No ] Interlock System Functional Requirements The functional requirements for interlock systems shall be as specified in Not all conditions conducive to a furnace implosion are detected by any of the mandatory automatic-trip devices, even though such devices are adjusted and maintained in accordance with the manufacturer's instructions and as required by this standard; therefore, operating personnel shall be made aware of the limitations of the automatic protection system. Submitter Full Name: [ Not Specified ] Organization: [ Not Specified ] Submittal Date: Wed Feb 27 15:08:50 EST 2013 Clause was included within the Clause 6.5 Furnace Implosion Protection to ensure that the readers do not overlook the requirements of clause Interlock System. The requirements of Clause is duplicated in and the appendix A Thus, deleting the clause does not change any of the requirements of an Interlock System but, only deleted duplications of requirements. Public Input No. 46-NFPA [Section No ]

154 Page 144 of 595 First Revision No. 187-NFPA [ Section No ] Fuel Gas Firing Special Problems. In addition to the common hazards involved in the combustion of solid, liquid, and gaseous fuels, the following special hazards related to the physical characteristics of fuel gas shall be addressed in the design of the firing systems: (1) Fuel gas is colorless; therefore, a leak is not visually detectable. In addition, detection of a fuel gas leak by means of odor is unreliable. (2) Leakage within buildings creates hazardous conditions, particularly where the fuel gas piping is routed through confined areas. (a) (b) Where the fuel gas piping is routed through confined areas, adequate ventilation shall be provided. Outdoor boilers tend to minimize confined-area problems. (3) The nature of fuel gas makes it possible to experience severe departures from design air-fuel ratios without any visible evidence at the burners, furnace, or stack that could escalate into a progressively worsening condition. (a) (b) Combustion control systems that respond to reduced boiler steam pressure or steam flow with an impulse for more fuel, unless protected or interlocked to prevent a fuel-rich mixture, are potentially hazardous. This hazard also applies to firing with fuel or air on manual without the previously mentioned interlocks or alarms. (See 6.4.1, 6.6.3, 6.6.4, and 6.6.5, which provide requirements, and Annex D.) (4) Special requirements as defined in NFPA 54, National Fuel Gas Code, must be taken with wet fuel gas systems. (5) Widely differing characteristics of fuel gas from either a single source or multiple sources could result in significant change in the heat input rate to the burners without a corresponding change in airflow. (6) Relief valves and atmospheric vents must discharge into areas away from building ventilation systems, sources of ignition, or other areas where the discharge fuel gases create a hazard to atmosphere in accordance with (7) Fuel gas piping must be purged prior to and after maintenance and repair, as detailed in NFPA 54, National Fuel Gas Code. Submitter Full Name: [ Not Specified ] Organization: [ Not Specified ] Submittal Date: Wed Feb 27 15:16:03 EST 2013

155 Page 145 of 595 Section provides additional requirements related to these type of vents and is referred to rather than repeating those requirements. Public Input No. 60-NFPA [Section No ]

156 Page 146 of 595 First Revision No. 188-NFPA [ Section No ] The requirement in shall be accomplished by providing full relieving capacity that is vented to a safe location discharged to atmosphere in accordance with or by providing a high fuel gas pressure trip when full relieving capacity is not installed. [See Figure A (b), which shows a typical fuel gas supply system outside the boiler room.] Submitter Full Name: [ Not Specified ] Organization: [ Not Specified ] Submittal Date: Wed Feb 27 15:19:32 EST 2013 The phrase safe location is not specific enough and thus has been determined by NFPA in the past to be unenforceable. This change utilizes language already included in NFPA 85 to provide more specifics related to the intent of this requirement. Public Input No. 61-NFPA [Section No ] Public Input No. 214-NFPA [Section No ]

157 Page 147 of 595 First Revision No. 189-NFPA [ Section No ] The discharge from atmospheric vents and relief valves shall be located so that there is no possibility of the discharged fuel gas being drawn into the air intake, ventilating system, or windows of the boiler room or adjacent buildings and shall be extended above the boiler and adjacent structures so that fuel gas discharge does not present a fire hazard in accordance with Submitter Full Name: [ Not Specified ] Organization: [ Not Specified ] Submittal Date: Wed Feb 27 15:21:35 EST 2013 Section provides additional requirements related to these type of vents and is referred to rather than repeating those requirements. Public Input No. 62-NFPA [Section No ]

158 Page 148 of 595 First Revision No. 190-NFPA [ Section No ] * Maintenance The burner equipment shall be in a location that allows access for maintenance The requirements of housekeeping in (8) shall be followed. Submitter Full Name: [ Not Specified ] Organization: [ Not Specified ] Submittal Date: Wed Feb 27 15:26:29 EST 2013 The text was added to in FR 127, therefore is deleted because it is redundant to chapter 4. Public Input No. 122-NFPA [Section No ]

159 Page 149 of 595 First Revision No. 191-NFPA [ Section No ] Sootblowers. Cleaning Devices Sootblowers, Sonic Horns, Air Cannons, and Pulse Detonation Devices Sootblowers Cleaning devices shall be operated only where heat input to the furnace is at a rate high enough to prevent a flameout during the sootblower cleaning device operation Sootblowers Cleaning devices shall not be operated at low load and high excess air conditions The use of wall sootblowers cleaning devices and high-temperature superheater and reheater sootblowers cleaning devices shall be permitted for cleaning during periods of unit outage if a unit purge has been completed and purge rate airflow is maintained The use of air heater sootblowers and SCR cleaning devices during startup shall be permitted. Submitter Full Name: [ Not Specified ] Organization: [ Not Specified ] Submittal Date: Wed Feb 27 15:32:48 EST 2013 NFPA 85 states specific requirements for the operation of sootblowers to prevent a hazardous condition from the re-entrainment of ash in the flue gas stream. Sonic horns, air cannons, and pulse detonation devices are beng used in boilers and SCRs to supplement and/or replace sootblowers for cleaning and could possibly result in the same hazardous conditions. Public Input No. 90-NFPA [Section No ] Public Input No. 112-NFPA [Section No ]

160 Page 150 of 595 First Revision No. 192-NFPA [ Section No (B) ] (B) The starting sequence shall be performed in the following order: (1) An open flow path from the inlets of the FD fans through the stack shall be verified. (2) An ID fan, if provided, shall be started; an FD fan then shall be started. Additional ID fans or FD fans shall be started in accordance with 6.5.3, as necessary, to achieve purge flow rate. (3) Dampers and burner registers shall be opened to the purge position in accordance with the open register purge method objectives outlined in (4) The airflow shall be adjusted to purge airflow rate, and a unit purge shall be performed. Special provisions shall be utilized as necessary to prevent the hazardous accumulation of volatile vapors that are heavier than air or to detect and purge accumulations in the furnace bottom. (5) The main fuel control valve shall be closed and the main safety shutoff valve(s) shall be opened, but only after the requirements of for leak test requirements and for permissive conditions in the unit purge system have been satisfied. (6) It shall be determined that the main fuel control valve is closed, and the following procedures shall be performed: (a) The main fuel bypass control valve, if provided, shall be set to maintain the necessary burner header fuel pressure for light-off. (b) The burner headers shall be vented in order to be filled with fuel gas and to provide a flow (if necessary) so that the main fuel and bypass fuel control valves function to regulate and maintain the correct pressure for burner light-off. (c) The main fuel control valve shall be opened when necessary. (d) The time needed to vent for control of header pressure after header charging shall be evaluated and minimized. (7) The igniter safety shutoff valve shall be opened, and the following shall be performed: (a) It shall be confirmed that the igniter fuel control valve is holding the manufacturer's recommended fuel pressure necessary for the igniter to operate at design capacity. (b) The igniter headers shall be vented in order to be filled with fuel gas and to provide a flow (if necessary) so that the igniter fuel control valve functions to regulate and maintain the pressure within design limits specified by the manufacturer for lighting the igniters. (c) The time needed to vent for control of header pressure after header charging shall be evaluated and minimized.

161 Page 151 of 595 (8) The air register or damper on the burner selected for light-off shall be adjusted to the position recommended by the manufacturer or the established operating procedure, in accordance with (C) through (F). (9) The spark or other source of ignition for the igniter(s) on the burner(s) to be lit shall be initiated, and the procedure shall continue as follows: (a) The individual igniter safety shutoff valve(s) shall be opened, and all igniter system atmospheric vent valves shall be closed. (b) If flame on the first igniter(s) is not established within 10 seconds, the individual igniter safety shutoff valve(s) shall be closed and the cause of failure to ignite shall be determined and corrected. (c) With airflow maintained at purge rate, repurge shall not be required, but at least 1 minute shall elapse before a retrial of this or any other igniter is attempted. (d) Repeated retrials of igniters without investigating and correcting the cause of the malfunction shall be prohibited. (10) Where Class 3 special electric igniters are used, the procedures described in (B)(1) through (B)(6), (B)(8), and (B)(11) through (B)(14) shall be used, consistent with the the requirements for individual main burner flame supervision. (11) After making certain that the igniter(s) is established and is providing the required level of ignition energy for the main burner(s), the following shall be performed: (a) The individual burner safety shutoff valve(s) shall be opened and the individual burner atmospheric vent valves shall be closed. (b) Except where associated Class 1 igniters are in service, a master fuel trip shall be initiated when the flame detection system(s) indicates that ignition has not been obtained within 5 seconds of the time the main fuel actually begins to enter the furnace. (c) Purging shall be repeated, and the conditions that caused the failure to ignite shall be corrected before another light-off attempt is made. (d) For the following burner and all subsequent burners placed in operation, failure to ignite or loss of ignition for any reason on any burner(s) shall cause fuel flow to that burner(s) to stop. (e) All conditions required by the manufacturer or by established operating procedures for light-off shall exist before restarting the burner(s). (12) After stable flame is established, the air register(s) or damper(s) shall be adjusted slowly to its operating position, making certain that ignition is not lost in the process. With automatic burner management systems, the air register shall be permitted to be opened simultaneously with the burner safety shutoff valve. (13) Class 3 igniters shall be shut off at the end of the time trial for proving the main flame, and the following shall be verified: (a) The stable flame continues on the main burners after the igniters are shut off.

162 Page 152 of 595 (b) The systems that allow the igniters to remain in service on either an intermittent or a continuous basis have been tested to meet all the requirements of Class 1 igniters or Class 2 igniters with associated interlocks in service. (14) After stable burner header pressure control has been established, the burner header atmospheric vent valve shall be closed. (15) * The sequence shall continue as follows: (a) The procedures in (B)(8) through (B)(13) shall be followed for placing additional burners with open registers in service, as necessary, to raise steam pressure or to carry additional load. (b) If used, automatic control of burner fuel flow and burner airflow during the lighting and start-up sequence shall be in accordance with the requirements of (B)(17). (c) The fuel flow to each burner (as measured by the burner fuel header pressure) shall be maintained at a controlled value that is compatible with the established airflow through the corresponding burner. (d) The established airflow through each open register shall be permitted to be maintained by controlling the windbox-to-furnace differential. (e) Total furnace airflow shall not be reduced below purge rate airflow and shall be at least that which is necessary for complete combustion in the furnace. (f) If it is necessary to vary fuel header pressure to eliminate a problem of having excessive lighting off and shutting down of burners, such variations shall be limited to a predetermined range. (g) This range shall be a function of the incremental fuel input that is added by the lighting of a single burner or gang of burners. (16) The maximum number of burners shall be placed in service consistent with the anticipated continuous load and the operating range of fuel header pressures. (17) The on-line metering combustion control (unless designed specifically for start-up procedures) shall not be placed into service until the following have occurred: (a) A predetermined minimum main fuel input has been attained. (b) All registers on nonoperating burners are closed unless compensation is provided for by the control system. (c) The burner fuel and airflow are adjusted as necessary. (d) Stable flame and specified furnace conditions have been established. (18) It shall be permitted to place a multiple number of igniters in service that are served simultaneously from a single igniter safety shutoff valve, provided that the igniters are reliably supervised, so that failure of one of the group to light causes the fuel to all igniters in the group to shut off.

163 Page 153 of 595 (19) It also shall be permitted to place in service simultaneously a multiple number of burners served by their corresponding multiple igniters from a single burner safety shutoff valve, provided that the burners are reliably supervised, so that failure of one of the group to light causes the fuel to all burners in the group to shut off. (20) On units with an overfire air system, the overfire air control damper positions shall be permitted to be changed only when repositioning of all burner air registers or burner air dampers is permitted. (21) On units with an overfire air system, the boiler shall be operating in a stable manner before the overfire air is introduced. The introduction of the overfire air shall not adversely affect boiler operation. (22) On units with an overfire air system and a reburn system, the overfire air shall be placed in operation before the reburn fuel sequence is started. (23) A reburn system shall be placed in service only after the following have occurred: (a) The boiler shall be operating at a load that ensures the introduction of the reburn fuel will not adversely affect continued boiler operation. (b) The temperature in the reburn zone shall be maintained in accordance with (c) The boiler shall be operating in a stable manner before the reburn start-up sequence is initiated. Submitter Full Name: [ Not Specified ] Organization: [ Not Specified ] Submittal Date: Wed Feb 27 15:49:07 EST 2013 The revision corrects the cross-reference in (5) to Public Input No. 145-NFPA [Section No (B)]

164 Page 154 of 595 First Revision No. 223-NFPA [ Section No ] The reburn injection rate shall be regulated within the design limits of the reburn equipment. (A) Air flow lead and lag shall be used during changes in the reburn fuel injection rate. (B) Reburn safety shutoff valves shall be fully open or completely fully closed, and shall not be placed in intermediate positions to regulate reburn injection rate. (C) Intermediate settings shall not be used. Submitter Full Name: [ Not Specified ] Organization: [ Not Specified ] Submittal Date: Tue Mar 05 15:55:07 EST 2013 The paragraph is revised to combine items (B) and (C) because there was confusion about what (C) referred to.

165 Page 155 of 595 First Revision No. 24-NFPA [ Section No ] After completion of the unit purge, forced and induced draft fans shall be permitted to be shut down. closing the burner air registers and shutting down the forced draft fans and induced draft fans shall be permitted to be optional; however, maintaining airflow through the unit to prevent accumulation of combustible gases is a prudent procedural step due to the potential of fuel leak-by * After shutting down the forced and induced draft fans, dampers in the flue gas path shall be permitted to be closed. Submitter Full Name: Kimberly Shea Organization: National Fire Protection Assoc Submittal Date: Fri Jan 11 12:11:57 EST 2013 The committee separated the requirements into new paragraphs, revised the language for clarity.

166 Page 156 of 595 First Revision No. 27-NFPA [ Section No ] Leakage of main or igniter fuel into the furnace or windbox shall be prevented. Submitter Full Name: Kimberly Shea Organization: National Fire Protection Assoc Submittal Date: Fri Jan 11 12:22:57 EST 2013 The committee deleted the subparagraph because it cotnains unenforceable laguage. In addtion, there are already several steps in the normal shutdown procedure that should prevent leakage of fuel.

167 Page 157 of 595 First Revision No. 186-NFPA [ Section No (A) ] (A) Interlocks shall be installed in accordance with and Submitter Full Name: [ Not Specified ] Organization: [ Not Specified ] Submittal Date: Wed Feb 27 15:11:50 EST 2013 Subsection was deleted in FR 185 because it is duplicative to Therefore, the duplicative cross-reference is also deleted.

168 Page 158 of 595 First Revision No. 177-NFPA [ Section No (B) ] (B) A master fuel trip shall result from any of the following conditions: (1) Fuel pressure at the burner below the minimum established by the manufacturer or by trial, and no other fuel proven in service. Where fuel pressure at the burner is not measurable, a low fuel gas pressure trip shall be provided upstream of the control valve. If another fuel is proven in service, this shall cause a fuel gas fuel trip, but not a master fuel trip. (2) Total airflow decreases below the minimum purge rate airflow as required in (A) by 5 percent design full load airflow. (3) Loss of either all induced draft fans or all forced draft fans. (4) Loss of all flame. (5) Partial loss of flame predetermined to be likely to introduce a hazardous accumulation of unburned fuel in accordance with Table (a), block 8. (6) Furnace positive or negative pressure in excess of the prescribed operating pressure by a value specified by the manufacturer. (7) All fuel inputs shut off in accordance with Table (a), block 9. (8) High fuel gas pressure and no other fuel proven in service. If another fuel is proven in service, this shall cause a fuel gas fuel trip, but not a master fuel trip. (9) Low drum water level or low feedwater flow rate in accordance with Table (a), blocks 10a and 10b. Submitter Full Name: [ Not Specified ] Organization: [ Not Specified ] Submittal Date: Wed Feb 27 11:23:36 EST 2013 The paragraph is updated to be consistent with changes made in FR 160 on Figure Public Input No. 87-NFPA [Section No ]

169 Page 159 of 595 First Revision No. 178-NFPA [ Section No ] Mandatory Master Fuel Trips with Alarms Not Necessarily Automatically Initiated. A master fuel trip shall result from any of the following conditions: l oss of energy supply for boiler control, burner management, or interlock systems. L oss of energy supply for boiler control, burner management, or interlock systems Furnace negative pressure in excess of the value specified by the manufacturer (See ) Submitter Full Name: [ Not Specified ] Organization: [ Not Specified ] Submittal Date: Wed Feb 27 11:27:17 EST 2013 Item (2) is relocated to in accordance with action taken in FR 160 on Figure

170 Page 160 of 595 First Revision No. 197-NFPA [ Section No ] Fuel Oil Firing Special Problems. In addition to the common hazards involved in the combustion of solid, liquid, and gaseous fuels, the following special hazards related to the physical characteristics of fuel oil shall be addressed in the design of the firing systems (see Section K.6K.6 L.6K.6): (1) Piping systems shall be designed to prevent leakage. (2) Limits to maintain atomization shall be in accordance with design parameters. (3) Fuel oil piping systems shall be designed to prevent water or sludge from plugging strainers or burner tips. (4) Combustion airflow shall follow changes in calorific content of fuel. [See Section K.3 K.3 L.3 K.3 (4).] (5) On installations designed to fire both heated and unheated fuel oils, the burner control system shall be designed to ensure that interlocks are activated for the selected fuel oil. The fuel oil piping supply to the burner as well as the fuel oil-recirculating piping to the fuel storage tanks shall be provided with interlocks, depending on the arrangement of the equipment provided. (6) Fuel oil guns shall not be inserted without a tip or sprayer plate and new gasket. (7) Pumping and atomization of fuel oils are dependent on control of viscosity. Changes in viscosity in relation to temperature vary for different fuel oils and blends of fuel oils. Viscosity control systems shall be designed for each fuel where the source or properties are variable. (8)* Because clear distillate fuels have low conductivities and generate static electrical charges in the fuel stream, flowing velocities shall be limited. (9) Piping systems shall prevent flow transients caused by operation of system valves. [See Section K.3 K.3 L.3 K.3 (8).] (10) * Operation of air heater sootblowers cleaning devices shall be in accordance with the requirements of the air heater manufacturer. Submitter Full Name: [ Not Specified ] Organization: [ Not Specified ] Submittal Date: Wed Feb 27 16:00:48 EST 2013 Notes: The term sootblowers is changed to cleaning devices to be consistent with FR 191.

171 Page 161 of 595 Date Submitted By Apr 8, 2013 K. Ritchie 6.7.2(7) - 2nd sentence is explanatory in nature; consider rephrasing or moving to Annex A? Public Input No. 113-NFPA [Section No ]

172 Page 162 of 595 First Revision No. 198-NFPA [ Section No ] * Relief valve discharge passages, vents, and telltales shall be provided with suitable piping to allow safe discharge of fuel oil, vapors, or toxic fumes in accordance with the requirements of Submitter Full Name: [ Not Specified ] Organization: [ Not Specified ] Submittal Date: Wed Feb 27 16:02:13 EST 2013 The revision removes unenforceable language and references requirements in chapter 4. Public Input No. 216-NFPA [Section No ]

173 Page 163 of 595 First Revision No. 199-NFPA [ Section No ] * Maintenance The burner equipment shall be in a location that allows access for maintenance The requirements of housekeeping in (8) shall be followed. Submitter Full Name: [ Not Specified ] Organization: [ Not Specified ] Submittal Date: Wed Feb 27 16:04:06 EST 2013 The language has been added by the Fundamentals committee to in FR 127. Therefore, the language is deleted because it is redundant to chapter 4. Public Input No. 124-NFPA [Section No ]

174 Page 164 of 595 First Revision No. 201-NFPA [ Section No ] Sootblowers Cleaning Devices Sootblowers, Sonic Horns, Air Cannons, and Pulse Detonation Devices Sootblowers Cleaning devices shall be operated only where heat input to the furnace is at a rate high enough to prevent a flameout during the sootblower operation Sootblowers Cleaning devices shall not be operated at low load and high excess air conditions The use of wall sootblowers cleaning devices and high temperature superheater and reheater sootblowers shall be permitted for cleaning during periods of unit outage if a unit purge has been completed and purge rate airflow is maintained The use of air heater sootblowers and SCR cleaning devices during startup shall be permitted Operation of air heater sootblowers cleaning devices shall be in accordance with the requirements of the air heater manufacturer. Submitter Full Name: [ Not Specified ] Organization: [ Not Specified ] Submittal Date: Wed Feb 27 16:09:36 EST 2013 NFPA 85 states specific requirements for the operation of sootblowers to prevent a hazardous condition from the re-entrainment of ash in the flue gas stream. Sonic horns, air cannons, and pulse detonation devices are being used in boilers and SCRs to supplement and/or replace sootblowers for cleaning and could possibly result in the same hazardous conditions. Public Input No. 114-NFPA [Section No ]

175 Page 165 of 595 First Revision No. 224-NFPA [ Section No ] The reburn injection rate shall be regulated within the design limits of the reburn equipment. (A) Airflow lead and lag shall be used during changes in the reburn fuel injection rate. (B) Reburn safety shutoff valves shall be fully open or completely closed. fully closed and shall not be placed in intermediate positions to regulate reburn injection rate. (C) Intermediate settings shall not be used. Submitter Full Name: [ Not Specified ] Organization: [ Not Specified ] Submittal Date: Tue Mar 05 15:57:58 EST 2013 The subparagraph is revised to combine (B) and (C) because there was confusion about what (C) referred to.

176 Page 166 of 595 First Revision No. 28-NFPA [ Section No ] After completion of the unit purge, closing the burner air registers and forced and induced draft fans shall be permitted to be shut down. shutting down the FD fans and ID fans shall be permitted to be optional; however, maintaining airflow through the unit to prevent accumulation of combustible gases is a prudent procedural step due to the potential of fuel leak-by * After shutting down the forced and induced draft fans, dampers in the flue gas path shall be permitted to be closed. Submitter Full Name: Kimberly Shea Organization: National Fire Protection Assoc Submittal Date: Fri Jan 11 12:25:02 EST 2013 The committee separated the requirements into new paragraphs, revised the language for clarity, and moved the unenforceable language to the annex.

177 Page 167 of 595 First Revision No. 32-NFPA [ Section No ] Leakage of main or igniter fuel into the furnace or windbox shall be prevented. Submitter Full Name: Kimberly Shea Organization: National Fire Protection Assoc Submittal Date: Fri Jan 11 13:48:15 EST 2013 The committee deleted the subparagraph because it contains unenforceable language. In addition, there are already several steps in the normal shutdown procedure that should prevent leakage of fuel.

178 Page 168 of 595 First Revision No. 221-NFPA [ Sections , ] Mandatory Automatic Master Fuel Trips. (A) Interlocks shall be installed in accordance with and (B) A master fuel trip shall result from any of the following conditions: (1) Fuel and atomizing medium (if provided) to the burners outside the operating limits necessary to accomplish atomization as established by trial or by the burner manufacturer and no other fuel is proven in service. If another fuel is proven in service, this shall cause a fuel oil fuel trip, but not a master fuel trip. (2) Total airflow decreases below the minimum purge rate airflow as required in (A) by 5 percent design full load airflow. (3) Loss of either all ID fans or all FD fans. (4) Loss of all flame. (5) Partial loss of flame predetermined to be likely to introduce a hazardous accumulation of unburned fuel in accordance with Table (a), block 8. (6) Furnace positive or negative pressure in excess of the prescribed operating pressure by a value specified by the manufacturer. (7) All fuel inputs shut off in accordance with Table (a), block 9. (8) Low drum water level or low feedwater flow rate in accordance with Table (a), blocks 10a and 10b Mandatory Master Fuel Trips with Alarms Not Necessarily Automatically Initiated. A master fuel trip shall result from loss of energy supply for boiler control, burner management, or interlock systems. any of the following conditions: Loss of energy supply for boiler control, burner management, or interlock systems Furnace negative pressure in excess of the value specified by the manufacturer [See ] Submitter Full Name: [ Not Specified ] Organization: [ Not Specified ] Submittal Date: Tue Mar 05 15:12:03 EST 2013

179 Page 169 of 595 Subsection was deleted in FR 185 because it is duplicative to New item (8) is added and is updated to be consistent with changes made in FR 160 on Figure Public Input No. 88-NFPA [Section No ]

180 Page 170 of 595 First Revision No. 203-NFPA [ Section No ] The starting sequence of the first fuel (gas or coal) shall be complete, and the starting sequence of the second fuel (oil) shall be performed in the following order: (1) The main fuel oil control valve shall be closed and the main safety shutoff valve(s) shall be opened, but only after leak test requirements in have been met. (2) The starting sequence in (B)(7) through (B)(20) shall be followed. Exception : For sequence (B)(12), where fuel oil is the second fuel to be placed in service, a fuel oil trip shall be initiated when the flame detection system(s) indicates that ignition has not been obtained within 5 seconds of the time the fuel actually begins to enter the furnace. A master fuel trip shall not be required. Submitter Full Name: [ Not Specified ] Organization: [ Not Specified ] Submittal Date: Wed Feb 27 16:15:24 EST 2013 The cross-reference in (1) is corrected. Public Input No. 144-NFPA [Section No ]

181 Page 171 of 595 First Revision No. 200-NFPA [ Section No ] * Maintenance The burner equipment shall be in a location that allows access for maintenance The requirements of housekeeping in (8) shall be followed to prevent the accumulation of unburned coal. Submitter Full Name: [ Not Specified ] Organization: [ Not Specified ] Submittal Date: Wed Feb 27 16:06:53 EST 2013 The language has been added by the Fundamentals committee to in FR 127. Therefore, the language is deleted because it is redundant to chapter 4. Public Input No. 125-NFPA [Section No ]

182 Page 172 of 595 First Revision No. 202-NFPA [ Section No ] Sootblowers. Cleaning Devices Sootblowers, Sonic Horns, Air Cannons, and Pulse Detonation Devices Sootblowers Cleaning devices shall be operated only where heat input to the furnace is at a rate high enough to prevent a flameout during the sootblower cleaning device operation Sootblowers Cleaning devices shall not be operated at low load and high excess air conditions The requirements of and shall not preclude the use of wall sootblowers cleaning devices, and high-temperature superheater and reheater sootblowers cleaning devices shall be permitted for cleaning during periods of unit outage if a unit purge has been completed and purge rate airflow is maintained The use of air heater sootblowers and SCR cleaning devices during startup shall be permitted. Submitter Full Name: [ Not Specified ] Organization: [ Not Specified ] Submittal Date: Wed Feb 27 16:13:43 EST 2013 NFPA 85 states specific requirements for the operation of sootblowers to prevent a hazardous condition from the re-entrainment of ash in the flue gas stream. Sonic horns, air cannons, and pulse detonation devices are beng used in boilers and SCRs to supplement and/or replace sootblowers for cleaning and could possibly result in the same hazardous conditions. Public Input No. 91-NFPA [Section No ] Public Input No. 115-NFPA [Section No ]

183 Page 173 of 595 First Revision No. 225-NFPA [ Section No ] The reburn injection rate shall be regulated within the design limits of the reburn equipment. (A) Airflow lead and lag shall be used during changes in the reburn fuel injection rate. (B) Reburn shutoff valves shall be fully open or completely fully closed and shall not be placed in intermediate positions to regulate reburn injection rate. (C) Intermediate settings shall not be used. Submitter Full Name: [ Not Specified ] Organization: [ Not Specified ] Submittal Date: Tue Mar 05 15:59:43 EST 2013 The subparagraph is revised to combine (B) and (C) because there was some confusion about what (C) referred to.

184 Page 174 of 595 First Revision No. 31-NFPA [ Section No ] After completion of the unit purge, closing the burner air registers and shutting down the FD fans and ID fans shall be permitted to be optional; however, maintaining airflow through the unit to prevent accumulation of combustible gases is a prudent procedural step due to the potential of fuel leak-by forced and induced draft fans shall be permitted to be shut down * After shutting down the forced and induced draft fans, dampers in the flue gas path shall be permitted to be closed. Submitter Full Name: Kimberly Shea Organization: National Fire Protection Assoc Submittal Date: Fri Jan 11 13:46:24 EST 2013 The committee separated the requirements into new paragraphs, revised the language for clarity, and moved the unenforceable language to the annex.

185 Page 175 of 595 First Revision No. 33-NFPA [ Section No ] Leakage of main or igniter fuels into the unit shall be prevented. Submitter Full Name: Kimberly Shea Organization: National Fire Protection Assoc Submittal Date: Fri Jan 11 13:49:12 EST 2013 The committee deleted the subparagraph because it contains unenforceable language. In addition, there are already several steps in the normal shutdown procedure that should prevent leakage of fuel.

186 Page 176 of 595 First Revision No. 222-NFPA [ Sections , ] Mandatory Automatic Master Fuel Trips. (A) Interlocks shall be installed in accordance with and (B) A master fuel trip shall result from any of the following conditions: (1) Total airflow decreases below the minimum purge rate airflow as required in (A) by 5 percent of design full load airflow (2) Loss of either all FD fans or all ID fans (3) Loss of all flame (4) Partial loss of flame predetermined to be likely to introduce a hazardous accumulation of unburned fuel in accordance with Table (a), block 8 (5) Furnace positive or negative pressure in excess of the prescribed operating pressure by a value recommended by the manufacturer (6) All fuel inputs shut off in accordance with Table (a), block 9 (See for a list of the required interlocks and trips for individual pulverizer subsystems.) (7) Low drum water level or low feedwater flow rate in accordance with Table (a), blocks 10a and 10b Mandatory Master Fuel Trips with Alarms Not Necessarily Automatically Initiated. A master fuel trip shall result from any of the following conditions: (1) Failure of the first pulverizer subsystem to operate successfully under the conditions specified in (B)(12) and Table (a), block 12d (2) Loss of energy supply for combustion control, burner control, or interlock systems Furnace negative pressure in excess of the value specified by the manufacturer (See ) Submitter Full Name: [ Not Specified ] Organization: [ Not Specified ] Submittal Date: Tue Mar 05 15:18:30 EST 2013

187 Page 177 of 595 Subsection was deleted in FR 185 because it is duplicative to A new (7) was added and updated to be consistent with changes made in FR 160 on Figure Public Input No. 89-NFPA [Section No ]

188 Page 178 of 595 First Revision No. 173-NFPA [ Section No ] If it is impossible to restart for an extended time, a flow of air through the unit shall be maintained to prevent accumulations of combustible gases. Submitter Full Name: [ Not Specified ] Organization: [ Not Specified ] Submittal Date: Tue Feb 26 18:11:40 EST 2013 The paragraph is deleted because be consistent with action on (D). The committee recognizes that it is a common industry practice to "bottle up" a boiler to prevent heat loss.

189 Page 179 of 595 First Revision No. 151-NFPA [ Section No. 7.2 ] 7.2 Purpose. The purpose of this chapter is to establish minimum standards for the design, installation, operation, and maintenance of atmospheric fluidized bed boilers, associated fuel-burning systems, and related systems to contribute to safe operation within design limits and, in particular, to the prevention of furnace explosions and pressure excursions. Submitter Full Name: [ Not Specified ] Organization: [ Not Specified ] Submittal Date: Wed Feb 20 13:56:14 EST 2013 The objective of this suggested change is to replace "safe operation" as it is unenforceable language. Public Input No. 223-NFPA [Section No. 7.2]

190 Page 180 of 595 First Revision No. 11-NFPA [ Section No ] The HRSG system's required interlocks shall prevent starting of the combustion turbine unless the HRSG starting conditions are satisfied, which shall include but not be limited to the following: (1) The water levels in drum(s), if provided, are within the defined start-up range. (2) The feedwater supply system is available to respond to demand. (3) The pressure in steam or water spaces is not high. (4) The exit temperature of duct burner(s), if provided, is not high. (5) The position of stack closure, if provided, is correct. (6) The pressure in the HRSG enclosure is not high. The augmented air supply, if provided, is in operation. (See ) (7) Where a combustion turbine purge credit is being used, all fuel systems connected to the HRSG are satisfactorily isolated. Submitter Full Name: Jenny Depew Organization: NFPA Submittal Date: Fri Jan 11 11:31:49 EST 2013 The committee deleted subparagraph (7) because the starting sequence requires flow to be established through the combustion turbine prior to starting augmented air systems.

191 Page 181 of 595 First Revision No. 12-NFPA [ Section No ] The combustion turbine exhaust system's required interlocks shall prevent Where a HRSG is not provided, an interlock shall prohibit starting the combustion turbine unless the following starting conditions are satisfied: if the combustion turbine exhaust system pressure is high. The pressure in the combustion turbine exhaust ductwork is not high. The tempering air supply, if provided, is in operation. Submitter Full Name: Jenny Depew Organization: NFPA Submittal Date: Fri Jan 11 11:37:23 EST 2013 The committee modified paragraph because the starting sequence requires flow to be established through the combustion turbine prior to starting tempering air systems.

192 Page 182 of 595 First Revision No. 14-NFPA [ Section No ] Triple Block and Double Vent Valve Arrangement. Global FR-9 Hide Deleted Three stop valves or equivalent valves safety shutoff valves in series, with proof of closure, shall be provided in each the fuel line to the duct burner for units with combustion turbine purge credit provisions in accordance with A n a utomatic vent valve s shall be provided between each of these valves. The most downstream valve for a duct burner installation shall be located in each burner line (runner) in accordance with * Where individual burner safety shutoff valves are installed in accordance with , the individual burner safety shutoff valve shall be permitted to be the most downstream safety shutoff valve required in Submitter Full Name: Jenny Depew Organization: NFPA Submittal Date: Fri Jan 11 11:43:59 EST 2013 The committee replaced the term "stop valve" with "safety shutoff valve" for consistency with the rest of the document and NFPA 37. The committee removed the reference to "equivalent valves" because, for a duct burner system, only safety shutoff valves are used to stop fuel flow. It is the intent of the committee to enable designers and/or operators to use the individual burner safety shutoff valve, where provided in accordance with , as the most downstream safety shutoff valve when it is not practical to install the third shutoff valve in the main fuel supply line. The previous text was worded to require the individual burner safety shutoff valves to be used as the "third valve".

193 Page 183 of 595 First Revision No. 206-NFPA [ Section No ] * Relief valve outlets, vents, drains, and telltales shall be provided with piping to allow safe discharge of liquids or and vapors away from sources of ignition, combustion air intakes, building ventilation systems, or the windows of a boiler or HRSG room or adjacent buildings and shall be designed for the expected range of external temperatures and protected against mechanical damage. Submitter Full Name: [ Not Specified ] Organization: [ Not Specified ] Submittal Date: Thu Feb 28 10:21:18 EST 2013 The paragraph is revised because vents, drains, and telltales are not generally piped away from their location. The flow only occurs when personnel are in attendance. Relief valves are automatic devices and can operate at any time, and are generally provided with fixed discharge piping. Therefore, the requirement is limited to relief valve discharge piping and guidance is added to the annex to advise users on discharge from vents, drains, and telltales.

194 Page 184 of 595 First Revision No. 208-NFPA [ Section No ] The ignition transformer shall not be energized before the duct burner ( HRSG enclosure ) purge is completed, and shall be de-energized at the end of the igniter trial for the ignition period. Submitter Full Name: [ Not Specified ] Organization: [ Not Specified ] Submittal Date: Thu Feb 28 11:38:22 EST 2013 HRSG enclosure purge is not a defined term. There are defined terms for HRSG Enclosure, HRSG Purge, Duct Burner Purge and Combustion Turbine Purge. The definition for HRSG Purge is a reference to other definitions and not a definition in itself; therefore not a clear requirement for Since this requirement is part of HRSG Fuel-Burning System, Duct Burner Purge seems to be appropriate requirement instead of Combustion Turbine Purge. Public Input No. 197-NFPA [Section No ]

195 Page 185 of 595 First Revision No. 209-NFPA [ Section No ] Expansion provisions shall be made for the movement of between the combustion turbine exhaust duct and the HRSG enclosure and or other combustion turbine exhaust systems. Submitter Full Name: [ Not Specified ] Organization: [ Not Specified ] Submittal Date: Thu Feb 28 11:48:01 EST 2013 By definition the combustion turbine exhaust duct is part of the HRSG enclosure, therefore the requirement is clarified that the expansion provisions are between the combustion turbine exhaust and the HRSG enclosure. Public Input No. 198-NFPA [Section No ]

196 Page 186 of 595 First Revision No. 210-NFPA [ Sections 8.6.2, ] All wiring shall comply with the requirements of NFPA 70, National Electrical Code All high voltage equipment shall be marked in accordance with the requirements of NFPA 70, National Electrical Code. Submitter Full Name: [ Not Specified ] Organization: [ Not Specified ] Submittal Date: Thu Feb 28 12:25:00 EST 2013 NFPA 70 is not applicable to electric utility power plants. Therefore, these two paragraphs are removed, making NFPA 85 silent on the electrical wiring and marking of high voltage equipment requirements. The Authority Having Jurisdiction should determine the appropriate electrical wiring and marking requirements for applications in their jurisdiction.

197 Page 187 of 595 First Revision No. 211-NFPA [ Section No ] The pressure at the gas flowmeter shall be monitored at the upstream tap if the gaseous fuel flowmeter is part of the combustion HRSG control system and is not pressure compensated. Submitter Full Name: [ Not Specified ] Organization: [ Not Specified ] Submittal Date: Thu Feb 28 12:28:36 EST 2013 Combustion Control System is a defined term which contains phrases or concepts not applicable to Chapter 8 such as furnace fuel, air inputs, air -fuel ratio. The phrase HRSG Control System is a defined term that is more applicable here. Public Input No. 202-NFPA [Section No ]

198 Page 188 of 595 First Revision No. 17-NFPA [ Section No ] Interlock functions including those functions outside the burner management system shall meet the functional requirements of shall be initiated by one or more of the following: A switch or transmitter independent of control functions and signals Two analog signals with a divergence alarm Three analog signals employing an auctioneering system and a divergence alarm or other fault diagnostic alarm Submitter Full Name: Jenny Depew Organization: NFPA Submittal Date: Fri Jan 11 12:02:15 EST 2013 The committee deleted the requirement and referenced the chapter 4 material to eliminate redundancy in the code. Public Input No. 154-NFPA [Section No ]

199 Page 189 of 595 First Revision No. 212-NFPA [ Section No ] Duct Burner Master Fuel Trip. For an operating duct burner, including the start-up or shutdown sequences, a duct burner master fuel trip shall be initiated by the following conditions: (1) Low fuel pressure (2) Combustion turbine exhaust or fresh air (if provided) flow across the duct burner that drops below the minimum required for operation of the duct burner as specified by the burner manufacturer or as proven by trial; it is permitted to infer this flow from the operating status of the combustion turbine, fresh air fan (if provided), and damper(s) (if provided) position(s) (3) Combustion turbine trip except for systems operating as defined in (4) Loss of all burner flame other than during a normal duct burner shutdown sequence (5) Partial loss of flame determined to create a hazardous accumulation of unburned fuel at any burner element or zone (6) Loss of duct burner element(s) resulting in incorrect element firing configuration, in accordance with (7) Light-off failure of first burner in multiple burner operation (8) Failure to prove a safety shutoff valve closed on command to close (9) Closing of last individual burner safety shutoff valve other than during a normal duct burner shutdown sequence (10) High fuel pressure (11) Low water level on high pressure section of HRSG (12) Loss of energy supply for boiler HRSG control, burner management, or interlock system (13) Low atomizing media (if provided) supply pressure (14) Detection of burner management system malfunction (15) Manual trip [See (8).] (16) Loss of augmented air supply where the operation of the duct burner requires augmented air (17) Fresh air (if provided) transfer failure (See ) (18) Logic controller failure [See (10) and (11).] Submitter Full Name: [ Not Specified ] Organization: [ Not Specified ] Submittal Date: Thu Feb 28 12:29:45 EST 2013

200 Page 190 of 595 Change from boiler control to HRSG control in (12) as shown. Definition of boiler refers to furnace which is not representative of HRSGs. HRSG is a defined term and more fitting than boiler. Public Input No. 201-NFPA [Section No ]

201 Page 191 of 595 First Revision No. 213-NFPA [ Section No ] Burner management system logic shall be maintained either in nonvolatile storage or in other memory that retains information on the loss of system power. Submitter Full Name: [ Not Specified ] Organization: [ Not Specified ] Submittal Date: Thu Feb 28 13:18:13 EST 2013 This paragraph is redundant with (12). Public Input No. 203-NFPA [Section No ]

202 Page 192 of 595 First Revision No. 20-NFPA [ Section No ] * Combustion Turbine Purge Process. The purge of the combustion turbine shall be in accordance with the manufacturer's instructions and with the requirements of , or as applicable Where a combustion turbine or HRSG is provided with fuel systems for multiple fuels, the purge requirements for each type of fuel shall be met. Submitter Full Name: Jenny Depew Organization: NFPA Submittal Date: Fri Jan 11 12:06:58 EST 2013 The paragraph is revised to be consistent with changes made in FR37 to separate purge credit requirements for liquid fuel systems.

203 Page 193 of 595 First Revision No. 219-NFPA [ Section No ] Initial Combustion Turbine Purge and Light-Off. Purge prior to the light-off of the combustion turbine shall be accomplished by at least five volume changes at purge rate and for a duration of not less than 5 minutes. Global FR Purge Volume Purge prior to the light-off of the combustion turbine shall be accomplished by at least five volume changes and for a duration of not less than 5 minutes Hide Deleted This volume shall be calculated based on the following: Global FR-218 Hide Deleted The combustion turbine operating at full load with no supplementary HRSG firing (1) The volume from the combustion turbine inlet to the portion of the HRSG or other combustion turbine exhaust systems where the combustion turbine exhaust gas temperature is reduced to at least 56 C (100 F) below the lowest autoignition temperature of the fuel(s) for which the system has been designed (2) The temperature profile in the HRSG in (1) is based on the combustion turbine operating at full load with no supplementary HRSG firing In no case shall the volume in (2) be less than the volume of the HRSG enclosure between the combustion turbine outlet and the outlet of the first evaporator section in the HRSG. For other combustion turbine exhaust systems without heat recovery, the purge volume shall extend to the stack Purge Rate The purge rate shall provide the required velocity in the HRSG enclosure or other combustion turbine exhaust systems to ensure dilution and removal of combustible gases prior to turbine light-off The adequacy of this purge rate shall be demonstrated by one of the following methods: (1) During the purge of the combustion turbine, a flow rate of not less than 8 percent of full-load mass airflow is provided through the HRSG or other combustion turbine exhaust systems, regardless of damper leakage or degradation in the HRSG enclosure or exhaust system.

204 Page 194 of 595 (2)* An engineering model of the system from the outlet of the turbine to the outlet of the HRSG or other combustion turbine exhaust systems has been created, and purge adequacy has been demonstrated with flow testing performed at the equivalent purge conditions. (3) A HRSG or other combustion turbine exhaust system burning fuel(s) of equal density and with the same ductwork and stack geometry has been installed and has a documented history of successful start-ups performed in accordance with the manufacturer's recommendations and without occurrences of uncontrolled combustion of fuel accumulations in the HRSG or other combustion turbine exhaust system during turbine lightoff. (4) Provision of combustible gas analyzers that would prevent startup of the combustion turbine if combustible gas concentrations greater than 25 percent of the lower explosive limit (LEL) exist in the HRSG or other combustion turbine exhaust systems In the event that the combustion turbine cannot meet the requirements of , alternative or supplementary means to satisfy the flow requirements through the HRSG enclosure or other combustion turbine exhaust systems shall be provided * Where augmented air firing or tempering air is provided, a means shall be supplied for interlocking and purging the augmented or tempering air system prior to initiating shall be purged and during the combustion turbine purge in accordance with the combustion turbine and HRSG manufacturers' operating instructions. Submitter Full Name: [ Not Specified ] Organization: [ Not Specified ] Submittal Date: Thu Feb 28 18:28:30 EST 2013 Notes: Date Submitted By Feb 28, 2013 [ Not Specified ] The committee elevated the paragraph because it is the general requirement for purge, not specific to purge volume. Note - the result of the FR is to relocate existing to follow the title on

205 Page 195 of 595 First Revision No. 218-NFPA [ Section No ] This volume shall be calculated based on the following: Global FR-218 Hide Deleted The combustion turbine operating at full load with no supplementary HRSG firing (1) The volume from the combustion turbine inlet to the portion of the HRSG or other combustion turbine exhaust systems where the combustion turbine exhaust gas temperature is reduced to at least 56 C (100 F) below the lowest autoignition temperature of the fuel(s) for which the system has been designed (2) The temperature profile in the HRSG in (1) is based on the combustion turbine operating at full load with no supplementary HRSG firing. Submitter Full Name: [ Not Specified ] Organization: [ Not Specified ] Submittal Date: Thu Feb 28 18:14:21 EST 2013 The requirement is reordered because it was being misinterpreted. The temperature profile modifies the volume calculation in (1); it is not a separate calculation.

206 Page 196 of 595 First Revision No. 23-NFPA [ Section No ] * Where augmented air firing or tempering air is provided, a means shall be supplied for interlocking and purging the augmented or tempering air system prior to initiating shall be purged and during the combustion turbine purge in accordance with the combustion turbine and HRSG manufacturers' operating instructions. Submitter Full Name: Jenny Depew Organization: NFPA Submittal Date: Fri Jan 11 12:09:58 EST 2013 The committee recognized that did not clearly prevent operators from running the augmenting or tempering air fans while the combustion turbine is not in operation or purge. It is not good practice to have air flowing in the reverse direction into the combustion turbine and this reverse flow can come from the augmenting or tempering air system. Tempering air was added to the section because it was reported to the committee that there are tempering air systems other than those associated with SCRs.

207 Page 197 of 595 First Revision No. 30-NFPA [ Section No ] * Combustion Turbine Purge Credit for Gaseous Fuel Systems. Following a combustion turbine normal shutdown, combustion turbine purge credit shall be allowed permitted to be established for the next start-up event provided that one of the systems described in the following requirements are met for each combustion turbine and duct burner fuel system through is incorporated for each combustion turbine and duct burner fuel system. In addition, a positive means to prevent leakage of ammonia into the idle HRSG or other combustion turbine exhaust system shall be provided in accordance with * Combustion turbine and duct burner manufacturer's valve-proving requirements, fuel supply system requirements, and safety control system requirements shall be met A positive means to prevent leakage of ammonia into the idle HRSG or other combustion turbine exhaust system shall be provided in accordance with A triple block and double vent valve arrangement is installed on the combustion turbine in accordance with and is installed on the HRSG fuel burning system (if provided) in accordance with One of the following shall be used to establish the purge credit. (A)* Valve Proving Method. (1) Where provided, duct burner normal shutdown shall be accomplished. (2)* Combustion turbine normal shutdown shall be accomplished. (3) The vent valves shall remain in the fully open position as long as purge credit is established. (4) Fuel gas block and vent valve positions shall be continuously monitored. If continuous monitoring is lost or any valve deviates from its assigned position, purge credit is lost, and subsequent start of the combustion turbine requires a combustion turbine purge prior to lightoff, in accordance with (5) Pressures in the two double block and vent pipe sections shall be continuously monitored. If continuous monitoring is lost or either pressure indicates leakage, purge credit is lost, and subsequent start of the combustion turbine requires a combustion turbine purge prior to light-off, in accordance with (6) Prior to each start-up and following each normal shutdown, block valves shall be validated for gas leak tightness via a valve-proving system. As a minimum, the most downstream block valve shall be valve proved during the start-up sequence, and the middle block valve shall be valve proved during the shutdown sequence. The most downstream block valve shall be tested only when airflow is passing through the combustion turbine.

208 Page 198 of 595 (7) The combustion turbine purge credit period shall not exceed 8 days (192 hours). If a combustion turbine purge in accordance with is performed during the 8-day period, the combustion turbine purge credit is reinitiated for an 8-day period. (B)* Pressurized Pipe Section Method. (1) Where provided, duct burner normal shutdown shall be accomplished. (2)* Combustion turbine normal shutdown shall be accomplished. (3) The upstream vent valve shall remain in the fully open position, and the downstream vent valve shall remain in the fully closed position as long as purge credit is established. (4) Air or inert gas shall be introduced to create and maintain a pressurized pipe section between the middle and most downstream block valves. (5) Fuel gas block and vent valve positions shall be continuously monitored. If continuous monitoring is lost or any valve deviates from its assigned position, purge credit is lost and subsequent start-up of the combustion turbine requires a combustion turbine purge prior to light-off, in accordance with (6) Pressures in the two double block and vent pipe sections shall be continuously monitored. If continuous monitoring is lost or the pressure downstream of the middle block valve decreases to less than 20.7 kpa (3 psid) above the upstream pressure, purge credit is lost and subsequent start-up of the combustion turbine requires a combustion turbine purge prior to light-off, in accordance with (7) The combustion turbine purge credit period shall shall be considered to be maintained as long as the conditions in (B)(4), (5), and (6) are met. (8) Provisions shall be made to ensure that fuel cannot enter the air or inert gas supply line at any time * System 1 Gaseous Fuels. Triple block and double vent valve arrangement in accordance with the following requirements: (1)* Combustion turbine normal shutdown. (2) Fuel gas block and vent valve positions shall be continuously monitored. If continuous monitoring is lost or any valve deviates from its assigned position, purge credit is lost, and subsequent start of the combustion turbine requires a combustion turbine purge prior to lightoff, in accordance with (3) Pressures in the two double block and vent pipe sections shall be continuously monitored. If continuous monitoring is lost or either pressure indicates leakage, purge credit is lost, and subsequent start of the combustion turbine requires a combustion turbine purge prior to light-off, in accordance with (4) * Prior to each start-up and following each normal shutdown, block valves shall be validated for gas leak tightness via a valve-proving system. As a minimum, the most downstream block valve shall be valve proved during the start-up sequence, and the middle block valve shall be valve proved during the shutdown sequence. The most downstream block valve shall be tested only when airflow is passing through the combustion turbine.

209 Page 199 of 595 (5) The combustion turbine purge credit period shall not exceed 8 days (192 hours). If a combustion turbine purge in accordance with is performed during the 8-day period, the combustion turbine purge credit is reinitiated for an 8-day period * System 2 Gaseous Fuels with Pressurized Pipe Section. Triple block and double vent valve arrangement filled with an inert gas or air and maintained at a pressure that prevents gaseous fuel from entering the combustion turbine or duct burner in accordance with the following requirements: (1)* Combustion turbine normal shutdown. (2) Air or inert gas shall be introduced to create and maintain a pressurized pipe section between the middle and most downstream block valves. (3) Fuel gas block and vent valve positions shall be continuously monitored. If continuous monitoring is lost or any valve deviates from its assigned position, purge credit is lost and subsequent startup of the combustion turbine requires a combustion turbine purge prior to light-off, in accordance with (4) Pressures in the two double block and vent pipe sections shall be continuously monitored. If the continuous monitoring is lost or the pressure downstream of the middle block valve decreases to less than 20.7 kpa (3 psid) above the upstream pressure, purge credit is lost and subsequent start-up of the combustion turbine requires a combustion turbine purge prior to light-off, in accordance with (5) Combustion turbine purge credit period is maintained as long as the conditions in (2), (3), and (4) are met. (6) Provisions shall be made to ensure that fuel cannot enter the air or inert gas supply line at any time * System 3 Liquid Fuels with Pressurized Pipe Section. Triple block and double drain valve arrangement filled with an inert gas or air and maintained at a pressure that prevents liquid fuel from entering the combustion turbine or duct burner in accordance with the following requirements: (1)* Combustion turbine normal shutdown. (2) Air or inert gas shall be introduced to create and maintain a pressurized pipe section between the middle and most downstream block valves. (3) The liquid fuel block and drain valve positions shall be continuously monitored. If continuous monitoring is lost or any valve deviates from its assigned position, purge credit is lost and subsequent start of the combustion turbine requires a combustion turbine purge prior to light-off, in accordance with (4) Pressures in the two double block and drain pipe sections shall be continuously monitored. If the continuous monitoring is lost or the pressure downstream of the middle block valve decreases to less than 20.7 kpa (3 psid) above the upstream pressure, purge credit is lost and subsequent start-up of the combustion turbine requires a combustion turbine purge prior to light-off, in accordance with (5) The combustion turbine purge credit period is maintained as long as the conditions in (2), (3), and (4) are met.

210 Page 200 of 595 (6) Provisions shall be made to ensure that fuel cannot enter the air or inert gas supply line at any time An inert liquid shall be permitted to be used in lieu of inert gas if acceptable to the original equipment manufacturer. Submitter Full Name: Jenny Depew Organization: NFPA Submittal Date: Fri Jan 11 13:10:19 EST 2013 The committee restructured the paragraphs to be consistent with the NFPA Manual of Style. The introductory paragraph referred to systems being installed, but the subsequent subparagraphs described operational sequences. The committee separated the requirements from the sequences and renumbered accordingly. The committee added the requirement for a normal duct burner shutdown to make it clear that all systems must be in a "normal" condition in order for the combustion turbine purge credit to be established. The committee added the requirement for meeting the requirements of OEM of the combustion turbine to ensure that the integrity of the combustion turbine fuel systems and safety controls are maintained. This is particularly important for any retrofit installed to meet the combustion turbine purge credit requirements. Notes: Date Submitted By Apr 4, 2013 K. Ritchie (A) - deleted note '(Note: Renumber A here.)' Apr 4, 2013 Apr 4, 2013 Apr 4, 2013 Apr 4, 2013 Apr 4, 2013 Apr 4, 2013 Apr 4, 2013 Apr 8, 2013 K. Ritchie (A)(4) - sentence is currently explanatory in nature; change 'require' to 'shall require' or move to Annex A? K. Ritchie (A)(5) - sentence is currently explanatory in nature; change 'require' to 'shall require' or move to Annex A? K. Ritchie (A)(7) - sentence is currently explanatory in nature; change 'is' to 'shall be' or move to Annex A? K. Ritchie (B) - deleted note '(Renumber A here.)' K. Ritchie (B)(5) - sentence is currently explanatory in nature; change 'require' to 'shall require' or move to Annex A? K. Ritchie (B)(6) - sentence is currently explanatory in nature; change 'require' to 'shall require' or move to Annex A? K. Ritchie sentence is not enforceable as written; substitute 'shall be' for both instances of 'is'? K. Ritchie asterisks - most of these asterisks do not correspond to Annex A.

211 Page 201 of 595 Public Input No. 178-NFPA [Section No ]

212 Page 202 of 595 First Revision No. 37-NFPA [ Section No ] Combustion Turbine Purge Credit for Liquid Fuel Systems. Following a normal shutdown, combustion turbine purge credit shall be permitted to be established for the next start-up event provided that the following requirements are met for each combustion turbine and duct burner fuel system * Combustion turbine and duct burner manufacturer's fuel supply valve monitoring system requirements and safety control system requirements shall be met A positive means to prevent leakage of ammonia into the idle HRSG or other combustion turbine exhaust system shall be provided in accordance with A triple block and double drain valve arrangement is installed on the combustion turbine in accordance with and is installed on the HRSG fuel burning system (if provided) in accordance with One of the following shall be used to establish the purge credit. (A) Proof-of-Closure Method. (1) Where provided, duct burner normal shutdown shall be accomplished. (2)* Combustion turbine normal shutdown shall be accomplished. (3) The drain valves shall remain in the fully open position as long as purge credit is established. (4) Liquid fuel block and drain valve positions shall be continuously monitored. If continuous monitoring is lost or any valve deviates from its assigned position, purge credit is lost, and subsequent start of the combustion turbine requires a combustion turbine purge prior to lightoff, in accordance with (5) Pressures in the two double block and drain pipe sections shall be continuously monitored. If continuous monitoring is lost or either pressure indicates leakage, purge credit is lost, and subsequent start of the combustion turbine requires a combustion turbine purge prior to light-off, in accordance with (6) The combustion turbine purge credit period shall not exceed 8 days (192 hours). If a combustion turbine purge in accordance with is performed during the 8 day period, the combustion turbine purge credit is reinitiated for an 8 day period. (B)* Pressurized Pipe Section Method. (1) Where provided, duct burner normal shutdown shall be accomplished. (2)* Combustion turbine normal shutdown shall be accomplished. (3) Air or inert gas shall be introduced to create and maintain a pressurized pipe section between the middle and most downstream block valves.

213 Page 203 of 595 (4) The upstream drain valve shall remain in the fully open position, and the downstream drain valve shall remain in the fully closed position as long as purge credit is established. (5) The liquid fuel block and drain valve positions shall be continuously monitored. If continuous monitoring is lost or any valve deviates from its assigned position, purge credit is lost and subsequent start of the combustion turbine requires a combustion turbine purge prior to lightoff, in accordance with (6) Pressures in the two double block and drain pipe sections shall be continuously monitored. If the continuous monitoring is lost or the pressure downstream of the middle block valve decreases to less than 20.7 kpa (3 psid) above the upstream pressure, purge credit is lost and subsequent start-up of the combustion turbine requires a combustion turbine purge prior to light-off, in accordance with (7) The combustion turbine purge credit period is maintained as long as the conditions in (B)(4), (B)(5), and (B) (6) are met. (8) Provisions shall be made to ensure that fuel cannot enter the air or inert gas supply line at any time. (C)* Liquid Level Monitoring Method. (1) In addition to the triple block and double drain valve arrangement, a vertical pipe section shall be installed between the two most downstream block valves that includes a vertical rise above the liquid supply level with a vent valve installed at the top of the riser. (2) Where provided, duct burner normal shutdown shall be accomplished. (3)* Combustion turbine normal shutdown shall be accomplished. (4) The vent valve and drain valves shall remain in the fully open position as long as purge credit is established. (5) The block valves, drain valves, and the vent valve positions shall be continuously monitored. If continuous monitoring is lost or any valve deviates from its assigned position, purge credit is lost and subsequent start of the combustion turbine requires a combustion turbine purge prior to light-off, in accordance with (6) * The vertical riser between the two most downstream block valves shall be continuously monitored for the absence of liquid. If the continuous monitoring is lost or the liquid fuel level rises above the limit level, purge credit is lost and subsequent start-up of the combustion turbine requires a combustion turbine purge prior to lightoff, in accordance with (7) The combustion turbine purge credit period is maintained as long as the conditions in (B) (5), and (6) are met An inert liquid shall be permitted to be used in lieu of inert gas if acceptable to the original equipment manufacturer.

214 Page 204 of 595 Submitter Full Name: Jenny Depew Organization: NFPA Submittal Date: Fri Jan 11 14:42:15 EST 2013 Notes: The committee separated the purge credit requirements for liquid fuels from the requirements for gaseous fuels. The introductory paragraphs are repeated for completeness. The committee added the proof-of-closure method to enable operators of liquid-fuel fired units to establish purge credit without the use of an inert gas or air plug. Realizing that the plug provides an infinite time for purge credit, the proof-of-closure method only provides an 8 day limit. With multiple drains in the system between the safety shutoff valves that are gravity -fed to safe areas, and no pressure on the middle or downstream safety shutoff valves, there is minimal opportunity for fuel to leak into the combustion turbine or duct burner. The committee added the requirement for a normal duct burner shutdown to make it clear that all systems must be in a "normal" condition in order for the combustion turbine purge credit to be established. The committee added the requirement for meeting the requirements of OEM of the combustion turbine to ensure that the integrity of the combustion turbine fuel systems and safety controls are maintained. This is particularly important for any retrofit installed to meet the combustion turbine purge credit requirements. A new option was added to monitor liquid level between the two most downstream block valves on systems where providing an inert plug is impractical.

215 Page 205 of 595 Date Apr 4, 2013 Apr 4, 2013 Apr 4, 2013 Apr 4, 2013 Apr 4, 2013 Apr 4, 2013 Apr 4, 2013 Apr 4, 2013 Apr 4, 2013 Apr 4, 2013 Apr 4, 2013 Apr 8, 2013 Submitted By K. Ritchie sentence is not enforceable as written; substitute 'shall be' for both instances of 'is'? Jenny Depew (A)(4) - delete '?' or change it to asterisk, if Annex material is to be added; because 2nd sentence is explanatory in nature, change 'requires' to 'shall require', or move to Annex A? K. Ritchie (A)(5) - delete '?' or change it to asterisk, if Annex material is to be added; because 2nd sentence is explanatory in nature, change 'requires' to 'shall require', or move to Annex A? K. Ritchie (A)(6) - because 2nd sentence is currently explanatory in nature, change 'is' to 'require', or move to Annex A? K. Ritchie (B) - deleted '(Renumber A here)' K. Ritchie (B)(5) - because 2nd sentence is currently explanatory in nature, change 'requires' to 'shall require', or move to Annex A? K. Ritchie (B)(6) - because 2nd sentence is currently explanatory in nature, change 'requires' to 'shall require', or move to Annex A? K. Ritchie (B)(7) - because sentence is currently explanatory in nature, change 'is' to 'shall be', or move to Annex A? K. Ritchie (C)(5) - because 2nd sentence is currently explanatory in nature, change 'requires' to 'shall require', or move to Annex A? K. Ritchie (C)(6) - because 2nd sentence is currently explanatory in nature, change 'requires' to 'shall require', or move to Annex A? K. Ritchie (C)(7) - because sentence is currently explanatory in nature, change 'is' to 'shall be', or move to Annex A? K. Ritchie asterisks - most of these asterisks do not correspond to text in Annex A. Please advise. Public Input No. 129-NFPA [New Section after ] Public Input No. 182-NFPA [Section No ]

216 Page 206 of 595 First Revision No. 41-NFPA [ Section No [Excluding any Sub-Sections] ] The automated vent or drain valve associated with the main safety shutoff valves shall be opened * The duct burners shall be taken out of service in a manner that relieves fuel pressure in the pipe section between the two most downstream safety shutoff valves When the unit (combustion turbine and duct burner) is being taken out of service, the combustion turbine load shall be reduced in accordance with the manufacturer's shutdown procedures Required steam flow shall be maintained through the superheater Leakage of fuel into the unit shall be prevented. Submitter Full Name: Kimberly Shea Organization: National Fire Protection Assoc Submittal Date: Mon Jan 14 10:51:58 EST 2013 The committee recognizes that there is no specific requirement to open the vent or drain valves on a normal duct burner shutdown. Pressure should be relieved in the pipe section immediately upstream of the safety shutoff valve (s) closest to the duct burner during a shutdown to prevent the possibility of leakage into the HRSG.

217 Page 207 of 595 First Revision No. 40-NFPA [ Section No ] When establishing a combustion turbine purge credit in accordance with (B), the following procedure shall be implemented prior to combustion turbine shutdown for duct burners utilizing gaseous fuels (System 2) (Pressurized Pipe Section Method) : (1) Open both vent valves of the duct burner fuel supply. (2) Admit the blocking medium to purge any remaining fuel until the fuel level is less than 25 percent of the LEL. (3) Close the downstream (header) vent valve. (4) Establish and maintain the required blocking pressure Submitter Full Name: Jenny Depew Organization: NFPA Submittal Date: Fri Jan 11 15:28:40 EST 2013 The paragraph is revised to be consistent with changes made in FR30.

218 Page 208 of 595 First Revision No. 42-NFPA [ Section No ] When establishing a combustion turbine purge credit in accordance with , the following procedure shall be implemented prior to combustion turbine shutdown for duct burners utilizing liquid fuels (System 3) after scavenging in accordance with : (1) Open both drain valves of the duct burner fuel supply. (2) Admit the blocking medium to purge any remaining fuel. (3) Close the downstream (header) drain valve. (4) Establish and maintain the required blocking pressure. Submitter Full Name: Kimberly Shea Organization: National Fire Protection Assoc Submittal Date: Mon Jan 14 10:56:22 EST 2013 The paragraph was revised to be consistent with changes mdade in FR37.

219 Page 209 of 595 First Revision No. 44-NFPA [ Section No ] All vent valves shall be opened. The automated vent valve associated with the main safety shutoff valves shall be opened. Submitter Full Name: Kimberly Shea Organization: National Fire Protection Assoc Submittal Date: Mon Jan 14 11:19:59 EST 2013 The committee modified the requirement to make it clear that manual vent valves or any optional vent valves are not required to open on a duct burner master fuel trip.

220 Page 210 of 595 First Revision No. 46-NFPA [ Section No ] * Returning HRSG to Service. Where combustion turbine exhaust flow is to be reintroduced to the HRSG through operation of the stack diverter damper, the combustion turbine load and damper sequence of operation shall be considered by in accordance with the HRSG manufacturer s operating instructions. Submitter Full Name: Kimberly Shea Organization: National Fire Protection Assoc Submittal Date: Mon Jan 14 11:21:25 EST 2013 The committee recognizes that there is no specific requirement to open the vent or drain valves on a normal duct burner shutdown. Pressure should be relieved in the pipe section immediately upstream of the safety shutoff valve (s) closest to the duct burner during a shutdown to prevent the possibility of leakage into the HRSG.

221 Page 211 of 595 First Revision No. 215-NFPA [ Section No ] Each system's operating mode shall be evaluated to ensure safe operation within design limits during transfer from combustion turbine operation to fresh air firing mode and from fresh air firing mode to combustion turbine mode. Submitter Full Name: [ Not Specified ] Organization: [ Not Specified ] Submittal Date: Thu Feb 28 15:58:18 EST 2013 The term "safe operation" is removed because it is unenforceable. Public Input No. 224-NFPA [Section No ]

222 Page 212 of 595 First Revision No. 48-NFPA [ Section No ] 8.11 Combustion Turbine Exhaust System The requirements of Section 8.11 shall apply to combustion turbine exhaust systems, either with or without emissions control systems The purge requirements of shall be met Selective Catalytic Reduction (SCR) Systems When an SCR system is provided, the requirements of Section 4.16 shall be met A tempering air system shall be provided if required to meet catalyst temperature limitations * A means shall be supplied for interlocking and purging the The tempering air system prior to initiating, and shall be purged during, the combustion turbine purge in accordance with the combustion turbine manufacturer s operating instructions * Following a combustion turbine failure to start, the tempering air system shall be repurged. Combustion turbine exhaust flow shall be established prior to initiating tempering air flow. Submitter Full Name: Kimberly Shea Organization: National Fire Protection Assoc Submittal Date: Mon Jan 14 11:23:54 EST 2013 The committee recognized that 8.11 did not clearly prevent operators from running the tempering fans while the combustion turbine is not in operation or purge. It is not good practice to have air flowing in the reverse direction into the combustion turbine and this reverse flow can come from the tempering air system. The plant control system should be designed to have an interlock to ensure tempering fans are not running until combustion turbine purge is in progress. Existing was deleted because it is redundant to In addition, annex material was added to include an isolation damper with stack to allow tempering fans to operate when the combustion turbine is isolated.

223 FR 150 New Chapter 9

224 Chapter 9 Pulverized Fuel Systems 9.1 Application * This chapter shall cover only those fuels with a volatile content of 8 percent or greater on a moisture-free basis This chapter shall exclude those systems that have an oxygen content greater than 21 percent, which require special attention. 9.2 Purpose The purpose of this chapter shall be to establish minimum requirements for design, installation, operation, and maintenance of pulverized fuel systems This chapter shall apply to any retrofit that involves replacement of the entire pulverized fuel system as defined in and and For less than total system replacement, components shall meet the requirements of this chapter or the original code or standard of construction. 9.3 General * Functional Requirements Because fires and explosions are most likely to occur during start-up or shutdown or after an emergency trip, pulverized fuel systems and their components shall be designed for and capable of continuous operation Interruptions of pulverized fuel systems shall be kept to an absolute minimum because of the combustible and explosive nature of the pulverized fuels The pulverized fuel system shall be designed to meet the demands of the system that it serves over the required range of operation The pulverized fuel system shall be designed and operated to enable the safe removal of foreign material * Hazards in Pulverized Fuel Systems. Design, operation, control, and maintenance of a pulverized fuel system shall address inherent hazards. The prevention of such conditions shall include but not be restricted to the necessary control of the following: (1) Feeding of raw fuel into the pulverizer (2) Influx of hot air or flue gas into the pulverizer (3) Influx of tempering air into the pulverizer (4) Influx of vent air into the pulverizer

225 (5)* Influx of ambient air into negative-pressure indirect-fired systems The system arrangement shall be such that it provides only one possible direction of flow (i.e., from the points of entrance of fuel and air to the point of discharge), which can be either a furnace or a transport and collection system The system shall include indicators and annunciators that provide the operator with all necessary information about significant operating conditions, both normal and abnormal, throughout the system Construction Materials for Pressure Containment Materials that are used to meet strength requirements shall be ferrous materials and shall satisfy the strength requirements of at design operating temperatures If made of steel or other ductile metals, the allowable stress values shall be determined as specified in through through Tension. The maximum allowable direct (i.e., membrane) stress shall not exceed the lesser of ¼ the ultimate strength or 5 8 the yield strength of the material Combined Bending and Membrane Stress (Where Bending Stresses Are Not Self-Limiting). The maximum allowable value of combined bending and membrane stress shall not exceed the lesser of the yield strength or ½ the ultimate strength of the material Combined Bending and Membrane Stress (Where Bending Stresses Are Self-Limiting). The maximum allowable values of combined self-limiting and non-selflimiting bending stresses plus membrane stress shall not exceed the ultimate strength of the material Compressive Stress. For components in which compressive stresses occur, in addition to the requirements of through through , the critical buckling stress shall be taken into account Fatigue Analysis. On components subject to cyclic loading, fatigue analysis shall be made to guard against possible fatigue failures. Both mechanical and thermal loading shall be analyzed If made of cast iron or other nonductile material, the allowable stress shall not exceed ¼ the ultimate strength of the material for all parts When cast iron or other nonductile material is used for flat areas exceeding m 2 (1 ft 2 ), the surface shall be strengthened by ribbing or other means An evaluation of the possibility of buckling and fatigue failures shall be made To ensure casting quality, nondestructive examination shall be made to detect significant defects at locations of high stress, at abrupt changes of section, and at sharp angles The choice of such a quality assurance program shall be the responsibility of the designer.

226 The justification of new materials or improved analytical methods shall be the responsibility of the designer If such materials and methods are used for the design of pulverized fuel system components, they shall meet the strength requirementsof and The materials that are used shall be capable of withstanding the conditions that could occur during abnormal incidents, such as pulverized fuel fires Rotary Valves. Where used as a means for deflagration isolation, rotary valves (material chokes) shall be installed and maintained in accordance with NFPA 69, Standard on Explosion Prevention Systems Electrical Equipment All electrical equipment and wiring shall conform to NFPA 70, National Electrical Code Locations where completely dusttight pulverized fuel systems are installed in compliance with this code shall not be considered a hazardous location for electrical equipment as defined in NFPA 70, National Electrical Code. 9.4 DesignDirect-Fired Pulverized Fuel Systems Introduction. General requirements for direct-fired pulverized fuel systems shall be covered by this section, and specific requirements for only the more commonly used directfired unit systems and storage systems shall be covered in detail. (For other types of systems, see Section ) The usual direct-firingfired pulverized fuel system shall be permitted to comprise the following components: (1) Raw fuel bunker (2) Raw fuel gate feed system (3) Raw fuel feederair and gas system (4) Flow control of raw fuel (5) Feeder discharge piping (6)(4) Air-swept pulverizer (5) Firing system (6) Emergency inerting system (7) Fire extinguishing system (19)(8) Safety interlocks and alarms (7) Classifier

227 (8) Foreign material collecting hopper (9) Pulverizer air fan or exhauster (10) Source of hot air (11) Source of tempering air (12) Temperature control of air (13) Flow control of air (14) Piping and ducts (15) Valves (16) Dampers (17) Burners (18) Means of inerting System Arrangement RequirementsRaw Fuel Bunker The system arrangement shall be such that it provides only one possible direction of flow (i.e., from the points of entrance of fuel and air to the point of discharge), which can be either a furnace or a transport and collection system The raw fuel bunker structural material shall be made of noncombustible material and shall be designed to provide the following mass flow and self-cleaning flow characteristics: (1) An uninterrupted flow of fuel being handled at a controlled rate (2) A flow pattern in which arching and ratholing (piping) are avoided The bunker outlet feeder(s) shall be coordinated with the bunker to avoid the probability that incorrect feeder selection will result in altering the bunker flow characteristics as specified in (1) or (2) Provisions shall be made to prevent the accumulation of flammable mixtures of air, fuel dust, and combustible gases within the bunker Procedures shall be established for emergency emptying of raw fuel bunkers * Water shall not be used to extinguish fires in the raw fuel bunker Piping Arrangement Raw Fuel Feeder System Means shall be provided to resist the passage of air or gas from the pulverizer through the feeder into the bunker * Where used as the means to resist passage of air or gas from the pulverizer, a vertical and cylindrical column of fuel shall be sized to withstand pulverizer

228 operating pressures, but it shall be no less than three pipe diameters or hydraulic diameters for noncircular pipe The primary air or flue gas supply shall be taken from a source with a pressure that is equal to or higher than that against which fuel will be discharged from the system The system shall include indicators and annunciators that provide the operator with all necessary information about significant operating conditions, both normal and abnormal, throughout the system Strength of Equipment The raw fuel feeder system, including but not limited to components falling within the requirements of through raw fuel feeding devices, discharge hoppers, and feed pipes to the pulverizer for a direct-fired system, shall begin at a point that includes a minimum coal column of is 0.61 m (2 ft) above the inlet of the raw fuel feeder, and shall end at the pulverizer inlet All components of the raw fuel feeder system shall be designed to withstand an internal explosion without rupture * All components of the raw fuel feeder system pulverized fuel system as described in that are designed to be operated at no more than gauge pressure of 13.8 kpa (2 psi) with a design coal having P max of 10 bar-g or less shall be designed to withstand an internal explosion gauge pressure for a maximum allowable working pressure of 344 kpa (50 psi) for containment of possible explosion pressures For operating gauge pressures in excess of 13.8 kpa (2 psi) and design coal P max of 10 bar-g or less, the raw fuel feeder system equipment as described in shall be designed to withstand an internal explosion gauge pressure for a maximum allowable working pressure 3.4 times the absolute operating pressure Where the design coal P max is greater than 10 bar-g, the raw fuel feeder system shall be designed to withstand internal explosion pressures calculated in accordance with NFPA 68, Standard on Explosion Protection by Deflagration Venting, or NFPA 69, Standard on Explosion Prevention Systems. In these calculations, normal unobstructed openings shall be permitted to be considered in the calculation as mitigation of explosion pressures Equipment design strength shall incorporate the combined stresses from mechanical loading, operating, and explosion and implosion pressures plus an allowance for wear, which shall be determined by agreement between the manufacturer and the purchaser * Shock wave pressures shall be included in the design, based on their locations in the system The raw fuel bunker and mechanical components, including but not limited to seals, gears, bearings, shafts, and drives, shall not be required to meet these requirements Explosion vents shall not be used on any component of the raw fuel feeder systemthat is described in

229 Valves All valves in the raw fuel feeder systempulverized fuel system from a point that includes a minimum coal column of within 0.61 m (2 ft) above the inlet of the raw fuel feeder to the point of consumption of the pulverized fuel shall have construction that is capable of withstanding pressures as defined in , , or , depending on the application These components shall include the following and any other raw fuel feeder system pulverized fuel system valves: (1) Barrier valve (2) Dusttight valve (3) Check valve (4) Pressure/air lock (5) Raw fuel gate Interconnections. Valves at points of interconnection between pulverized fuel system components requiring different design pressures shall comply with the strength requirements of the lower pressure of the two Air and Gas System The fan shall be permitted to be located upstream (primary air fan) or downstream (exhauster) of the pulverizer The primary air or flue gas supply shall be taken from a source with a pressure that is equal to or higher than that against which fuel will be discharged from the system If auxiliary air is used, a damper shall be placed in this the auxiliary air line Air Supply Isolation Requirements For pressurized pulverizers and suction pulverizers with pressurized air supply installations, there shall be a means for tight shutoff of the hot air supply and a means for shutting off the primary air supply to each pulverizer For suction pulverizer installations with an atmospheric tempering air supply, there shall be a means for shutting off the hot air supply * All ductwork, from the hot and tempering air supply ducts to individual pulverizers, including damper frames, expansion joints, supports, and hot primary air fans, shall be designed to contain the test block capability of the pulverizer air supply fan Air Swept Pulverizer System Strength of Equipment.

230 The pulverizer system components, including the pulverizer, the foreign-material collecting hopper, exhauster, and the external classifier, that are required for containment of internal pressure, shall be in accordance with All components of the pulverizer system shall be designed to withstand an internal explosion without rupture These components falling within the requirements of through for a direct-fired system shall begin at a point that includes a minimum coal column of is 0.61 m (2 ft) above the inlet of the raw fuel feeder, at the point of connection of ductwork to the pulverizer, and at the seal air connections to the pulverizer system, and they shall end at the discharge of the pulverizer, external classifier, or exhauster * All components of the pulverized fuel pulverizer system as described in that are designed to be operated at no more than gauge pressure of 13.8 kpa (2 psi) with a design coal having P max of 10 bar-g or less shall be designed to withstand an internal explosion gauge pressure for a maximum allowable working pressure of 344 kpa (50 psi) for containment of possible explosion pressures For operating gauge pressures in excess of 13.8 kpa (2 psi) and design coal P max of 10 bar-g or less, the pulverizer system equipment as described in shall be designed to withstand an internal explosion pressure for a maximum allowable working pressure 3.4 times the absolute operating pressure Where the design coal P max is greater than 10 bar-g, the raw fuel feeder system shall be designed to withstand internal explosion pressures calculated in accordance with NFPA 68, Standard on Explosion Protection by Deflagration Venting, or NFPA 69, Standard on Explosion Prevention Systems. In these calculations, normal unobstructed openings shall be permitted to be considered in the calculation as mitigation of explosion pressures Equipment design strength shall incorporate the combined stresses from mechanical loading, operating, and explosion and implosion pressures plus an allowance for wear, which shall be determined by agreement between the manufacturer and the purchaser * Shock wave pressures shall be included in the design, based on their locations in the system Explosion vents shall not be used on the components of the air-swept pulverizer system Valves All valves in the pulverizer system from a point that includes a minimum coal column of 0.61 m (2 ft) to the point of consumption of the pulverized fuel shall have construction that is capable of withstanding pressures as defined in or , depending on the application These components shall include the following and any other pulverized fuel system valves: (1) Barrier valve

231 (2) Dusttight valve (3) Check valve (4) Pressure/air lock (5) Raw fuel gate Interconnections. Valves at points of interconnection between pulverizer system components requiring different design pressures shall comply with the strength requirements of the lower pressure of the two Firing System Piping Arrangement Process ductwork and piping for pneumatic transportation of fuel shall be arranged to prevent hazardous accumulation of fuel Where the air-fuel stream is directed into multiple pipes, the system shall divide the air-fuel mixture into design ratio among various pipes Pipe Velocities Positive means shall be provided to ensure that all pipe velocities are equal to or above the minimum velocity required for pneumatic fuel transport and to prevent the hazardous accumulation of fuel and flashback from the burners Testing during initial start-up and retesting as appropriate shall be performed by the owner/operator or the owner s/operator s designated representative to verify that individual pipe velocities are adequate All piping system components shall be capable of being cleared of pulverized fuel using transport air * For systems that are normally operated at a gauge pressure no more than 13.8 kpa (2 psi), the The pulverized fuel piping from the outlet of the pulverizer system equipment, as defined in and ,to the pulverized fuel burner or storage bin shall comply with Bend Radii Pulverized fuel piping shall provide smooth flow and have bend radii not less than one pipe diameter Wherever possible, radii in excess of one pipe diameter shall be used Flexible joints and split clamp couplings shall conform to through except that the junction of two sections shall be permitted to be sealed with flexible material There shall be no separation of the pipe joint in case of failure of the flexible material.

232 Positive mechanical connections shall be provided between the two sections to prevent serious misalignment or separation At operating temperatures encountered in the service of the equipment, piping materials shall satisfy the strength requirements of and shall comply with for allowable stresses Brittle materials having a plastic elongation of less than 8 percent prior to tensile rupture shall not be used for piping except as abrasion-resistant linings and where no credit is taken for the structural strength of the lining Piping support systems shall be designed and installed in accordance with Chapter 2, Part 5, of ASME B31.1, Power Piping, so that combined stresses will not be in excess of those specified in Pipe that is lined with abrasion-resistant material shall have casing thickness and flange size that is designed for the strength requirements in with no required allowance for wear Prior to initial operation or after piping system renovation, an in-service leak test shall be performed by the owner/operator or the owner s/operator s designated representative in accordance with the following procedure: (1) The system shall be gradually brought up to operating pressure and temperature. (2) The system shall be held continuously at the conditions described in (1) for 10 minutes. (3) All joints and connections shall be examined for leakage. (4) The system shall show no visual evidence of weeping or leakage Valve Requirements For a suction furnace that can be fired by other main fuels or that is connected to two or more pulverizers or exhausters, valves, as shown in Figure details (c), (d), (e), (f), (g), (h), and (i), shall be installed to isolate all burner lines. ****INSERT FIGURE HERE**** FIGURE Direct-FiredFiring Pulverized Fuel System's Valve Requirements in Burner Piping. (A) This requirement shall be permitted to be met with one dusttight and one barrier valve or with two dusttight valves. (B) A dusttight valve shall be installed in the burner pipe close to the furnace. (C) The second valve shall be installed close to the pulverizer. (D) The valves shall be closed prior to entering a pulverizer, exhauster, or fuel piping.

233 For a pressure furnace that can be fired by other main fuels or that is connected to two or more pulverizers or exhausters, a dusttight valve, as shown in Figure , details (j), (k), and (l), shall be installed to isolate all burner lines. (A) In addition, a second dusttight valve shall be installed close to the furnace. (B) Both valves shall be closed prior to entering a pulverizer, exhauster, or fuel piping One of the valves in and shall be quick closing If one valve is used to isolate more than one burner line, means shall be provided to prevent circulation between those lines or burners Two dusttight valves or one dusttight valve and one barrier valve, as shown in Figure , details (g) and (h), shall be provided in each burner pipe if one or more pulverizers are connected to more than one suction furnace at a time Where one or more pulverizers, as shown in Figure , detail (l), are connected to two or more pressure furnace(s) at the same time, the valve requirements in shall apply Two dusttight valves or one dusttight valve and one barrier valve, as shown in Figure , detail (i), shall be installed in the burner piping where the discharge pipes from separate exhausters or pulverizers are connected to the same burner nozzle of a suction furnace Two dusttight valves, as shown in Figure , detail (k), shall be installed in the burner piping where the discharge pipes from separate exhausters or pulverizers are connected to the same burner nozzle of a pressure furnace The valve that is located nearest the pulverizer shall be positioned so that pulverized fuel accumulations above the valve will drain into the exhauster or pulverizer when the valve is opened. Other valves shall be located so as to prevent accumulation of pulverized fuel Figure (a) through Figure (f); Figure , details (a) through (l); and the accompanying text illustrate and specify requirements for the usual combinations of equipment; if other combinations are used, they shall conform to the principles set forth in this code Unless required by the inerting system, valves shall not be required between the pulverizer and the burners for a single pulverizer or exhauster connected to one or more burners in a furnace that cannot be fired by any other main fuel, provided that the combustion air to individual burners cannot be shut off [see Figure , details (a) and (b)]; if combustion air can be shut off to individual burners, and shall apply Valves.

234 All valves in the firing system from a point that includes a minimum coal column of 0.61 m (2 ft) to the point of consumption of the pulverized fuel shall have construction that is capable of withstanding pressures as defined in or , depending on the application These components shall include the following and any other pulverized fuel system valves: (1) Barrier valve (2) Dusttight valve (3) Check valve (4) Pressure/air lock (5) Raw fuel gate Interconnections. Valves at points of interconnection between firing system components requiring different design pressures shall comply with the strength requirements of the lower pressure of the two Auxiliary Systems Emergency Inerting System Pulverizers and pulverized fuel storage systems shall be equipped with an inerting system that is capable of maintaining an inert atmosphere as required to meet the provisions of (See also NFPA 69, Standard on Explosion Prevention Systems.) Provisions shall be made for verification of flow of inerting media when the system is activated Where an inerting system is required in accordance with , it shall be permanently installed and equipped with connections, which shall be a minimum of 25.4 mm (1 in.) in diameter Injection shall be controlled by readily operable valves or dampers. (See NFPA 69, Standard on Explosion Prevention Systems.) Operation of these valves shall be accomplished at a location that is remote from the pulverized fuel system Where these valves are manually operated, they shall be readily accessible Where these valves are manually operated, they shall be identified by a sign in block letters of not less than 51 mm (2 in.) in height on a background of contrasting color to the letters Fire-Extinguishing System Connections.

235 Pulverizers and pulverized fuel collecting systems shall be equipped with connections for fire extinguishing These connections shall be at least 25 mm (1 in.) in diameter and shall be adequate to pass the amount of required extinguishing material Provisions shall be made for verification of flow of fire-extinguishing media when the system is activated Safety Interlock Systems The safety interlocks required in this section shall be coordinated with the boiler, furnace, or other related devices to which the pulverized fuel system is connected Permissive Sequential-Starting Interlocks Permissive sequential-starting interlocks for direct-fired systems shall be arranged so that, after furnace or other connected apparatus interlocks have been satisfied, the pulverizer can be started only in the following sequence: (1) Start ignition system in accordance with Chapter 6. (2) Start primary air fan or exhauster. (3) Establish minimum airflow. (4) Start pulverizer. (5) Start raw fuel feeder The actions of (2) and (4) shall be permitted to be simultaneous Trip Sequence of Interlocks Interlocks for direct-fired pulverized fuel systems shall be arranged to trip in the following sequence: (1) Failure of primary airflow to below manufacturer's minimum shall trip the pulverizer and burner shutoff valve or equivalent and the feeder. The manufacturer's requirements regarding the burner's shutoff valve operation shall be followed. (2) Failure of pulverizer shall trip the feeder and primary airflow. (3) Closure of all fuel line valves shall trip the pulverizer, primary airflow, and raw fuel feed. (4) Failure of the feeder shall initiate an alarm; restarting of the feeder shall be blocked until feeder start-up conditions are re-established Means to indicate loss of fuel feed to the pulverizer or fuel input to the furnace shall be installed System Arrangements.

236 Direct-Fired Systems These systems, as shown in Figure (a) through Figure (f), shall be are permitted to have the fan located either following or ahead of the pulverizer. ****INSERT FIGURE HERE**** FIGURE (a) Direct-Firing Pulverized Fuel Exhauster System for Suction Furnace. ****INSERT FIGURE HERE**** FIGURE (b) Direct-Firing Pulverized Fuel Hot Primary Air Fan System for Suction Furnace. ****INSERT FIGURE HERE**** FIGURE (c) Direct-Firing Pulverized Fuel Exhauster System for Positive Pressure Furnace. ****INSERT FIGURE HERE**** FIGURE (d) Direct-Firing Pulverized Fuel Hot Primary Air Fan System for Pressure Furnace. ****INSERT FIGURE HERE**** FIGURE (e) Direct-Firing Pulverized Fuel Cold Primary Air Fan System for Pressure Furnace. ****INSERT FIGURE HERE**** FIGURE (f) Direct-Firing Pulverized Fuel Cold Primary Air Fan System for Suction Furnace If auxiliary air is used, a damper shall be placed in this line Valve Requirements For a suction furnace that can be fired by other main fuels or that is connected to two or more pulverizers or exhausters, valves, as shown in Figure details (c), (d), (e), (f), (g), (h), and (i), shall be installed to isolate all burner lines. ****INSERT FIGURE HERE**** FIGURE Direct-Firing Pulverized Fuel System's Valve Requirements in Burner Piping.

237 (A) This requirement shall be permitted to be met with one dusttight and one barrier valve or with two dusttight valves. (B) A dusttight valve shall be installed in the burner pipe close to the furnace. (C) The second valve shall be installed close to the pulverizer. (D) The valves shall be closed prior to entering a pulverizer, exhauster, or fuel piping For a pressure furnace that can be fired by other main fuels or that is connected to two or more pulverizers or exhausters, a dusttight valve, as shown in Figure , details (j), (k), and (l), shall be installed to isolate all burner lines. (A) In addition, a second dusttight valve shall be installed close to the furnace. (B) Both valves shall be closed prior to entering a pulverizer, exhauster, or fuel piping One of the valves in and shall be quick closing If one valve is used to isolate more than one burner line, means shall be provided to prevent circulation between those lines or burners Two dusttight valves or one dusttight valve and one barrier valve, as shown in Figure , details (g) and (h), shall be provided in each burner pipe if one or more pulverizers are connected to more than one suction furnace at a time Where one or more pulverizers, as shown in Figure , detail (l), are connected to two or more pressure furnace(s) at the same time, the valve requirements in shall apply Two dusttight valves or one dusttight valve and one barrier valve, as shown in Figure , detail (i), shall be installed in the burner piping where the discharge pipes from separate exhausters or pulverizers are connected to the same burner nozzle of a suction furnace Two dusttight valves, as shown in Figure , detail (k), shall be installed in the burner piping where the discharge pipes from separate exhausters or pulverizers are connected to the same burner nozzle of a pressure furnace The valve that is located nearest the pulverizer shall be positioned so that pulverized fuel accumulations above the valve will drain into the exhauster or pulverizer when the valve is opened. Other valves shall be located so as to prevent accumulation of pulverized fuel Figure (a) through Figure (f); Figure , details (a) through (l); and the accompanying text illustrate and specify requirements for the usual combinations of equipment; if other combinations are used, they shall conform to the principles set forth in this code Unless required by the inerting system, valves shall not be required between the pulverizer and the burners for a single pulverizer or exhauster connected to one or more burners in a furnace that cannot be fired by any other main fuel, provided that the combustion air to

238 individual burners cannot be shut off [see Figure , details (a) and (b)]; if combustion air can be shut off to individual burners, and shall apply Air Supply Isolation Requirements For pressurized pulverizers and suction pulverizers with pressurized air supply installations, there shall be a means for tight shutoff of the hot air supply and a means for shutting off the primary air supply to each pulverizer For suction pulverizer installations with an atmospheric tempering air supply, there shall be a means for shutting off the hot air supply These systems, as Common designs for indirect-firing systems are shown in Figure (a) through Figure (h), shall be arranged to permit partial or complete venting of the pulverizer air and water vapor after separating the pulverized fuel in cyclones or other types of dust collectors. ****INSERT FIGURE HERE**** FIGURE (a) Pulverized Fuel Storage Firing System. ****INSERT FIGURE HERE**** FIGURE (b) Pulverized Fuel Storage Firing System for Pressure Furnace. ****INSERT FIGURE HERE**** FIGURE (c) Pulverized Fuel Storage Firing System: Partial Recirculation Vented Air to Stack. ****INSERT FIGURE HERE**** FIGURE (d) Pulverized Fuel Storage Firing System: Partial Recirculation Vented Air to Stack. ****INSERT FIGURE HERE**** FIGURE (e) Storage Firing System: Partial Recirculation Vented Air to Primary Air Fan. ****INSERT FIGURE HERE**** FIGURE (f) Storage Firing System: Partial Recirculation Vented Air to Furnace. ****INSERT FIGURE HERE**** FIGURE (g) Storage Firing System: Partial Recirculation.

239 ****INSERT FIGURE HERE**** FIGURE (h) Storage Firing System: No Vent Fan, with Exhauster StorageIndirect-Fired Pulverized Fuel Systems Introduction. General requirements for indirect-fired pulverized fuel systems shall be covered by this section, and specific requirements for only the more commonly used indirectfired unit systems shall be covered in detail In addition to the components of a direct-fired system as listed in , a typical storage indirect-fired system shall include some or all of the following special equipment: (1) (2) (3) (4) Dust collectorpulverized Fuel-air separation Cyclone vent collectorpulverized fuel transport system Vent fanpulverized fuel storage Dust collector pressure lockseparated air (5) Transport system from the separator, cyclone, and dust collector to the pulverized fuel bin; pulverized fuel pump; piping; and valves or mechanical conveying system (6) Pulverized fuel bins (7) Pulverized fuel feeders Raw Fuel Bunker The raw fuel bunker structural material shall be made of noncombustible material and shall be designed to provide the following mass flow and self-cleaning flow characteristics: (1) An uninterrupted flow of fuel being handled at a controlled rate (2) A flow pattern in which arching and ratholing (piping) are avoided The bunker outlet feeder(s) shall be coordinated with the bunker to avoid the probability that incorrect feeder selection will result in altering the bunker flow characteristics as specified in (1) or (2) Provisions shall be made to prevent the accumulation of flammable mixtures of air, fuel dust, and combustible gases within the bunker Procedures shall be established for emergency emptying of raw fuel bunkers * Water shall not be used to extinguish fires in the raw fuel bunker Raw Fuel Feeder System Means shall be provided to resist the passage of air or gas from the pulverizer through the feeder into the bunker.

240 Where used as the means to resist passage of air or gas from the pulverizer, a vertical column of fuel shall be sized to withstand pulverizer operating pressures, but it shall be no less than three pipe diameters or hydraulic diameters for noncircular pipe Strength of Equipment The raw fuel feeder system, including but not limited to raw fuel feeding devices, discharge hoppers, and feed pipes to the pulverizer for an indirect-fired system, shall begin at a point that includes a minimum coal column of 0.61 m (2 ft), and shall end at the pulverizer inlet All components of the raw fuel feeder system shall be designed to withstand an internal explosion without rupture * All components of the raw fuel feeder system that are designed to be operated at no more than gauge pressure of 13.8 kpa (2 psi) with a design coal having P max of 10 bar-g or less shall be designed for a maximum allowable working pressure of 344 kpa (50 psi) for containment of possible explosion pressures For operating gauge pressures in excess of 13.8 kpa (2 psi) and design coal P max of 10 bar-g or less, the raw fuel feeder system shall be designed for a maximum allowable working pressure 3.4 times the absolute operating pressure Where the design coal P max is greater than 10 bar-g, the raw fuel feeder system shall be designed to withstand internal explosion pressures calculated in accordance with NFPA 68, Standard on Explosion Protection by Deflagration Venting, or NFPA 69, Standard on Explosion Prevention Systems. In these calculations, normal unobstructed openings shall be permitted to be considered in the calculation as mitigation of explosion pressures Equipment design strength shall incorporate the combined stresses from mechanical loading, operating, and explosion and implosion pressures plus an allowance for wear, which shall be determined by agreement between the manufacturer and the purchaser * Shock wave pressures shall be included in the design, based on their locations in the system The mechanical components, including but not limited to seals, gears, bearings, shafts, and drives, shall not be required to meet these requirements Explosion vents shall not be used on the components of the raw fuel feeder system Valves All valves in the raw fuel feeder system from a point that includes a minimum coal column of 0.61 m (2 ft) to the point of consumption of the pulverized fuel shall have construction that is capable of withstanding pressures as defined in or , depending on the application These components shall include the following and any other pulverized fuel system valves:

241 (1) Barrier valve (2) Dusttight valve (3) Check valve (4) Pressure/air lock (5) Raw fuel gate Interconnections. Valves at points of interconnection between pulverized fuel system components requiring different design pressures shall comply with the strength requirements of the lower pressure of the two Air and Gas System The fan for the pulverizer system shall be permitted to be located upstream (pulverizer fan) or downstream (exhauster) of the pulverizer Air Supply Isolation Requirements For pressurized pulverizers and suction pulverizers with pressurized air supply installations, there shall be a means for tight shutoff of the hot air supply and a means for shutting off the primary air supply to each pulverizer For suction pulverizer installations with an atmospheric tempering air supply, there shall be a means for shutting off the hot air supply * All ductwork, from the hot and tempering air supply ducts to individual pulverizers, including damper frames, expansion joints, supports, and hot primary air fans, shall be designed to contain the test block capability of the pulverizer air supply fan Air-Swept Pulverizer System Strength of Equipment The pulverizer system components, including the pulverizer, foreign-material collecting hopper, exhauster, and the external classifier, that are required for containment of internal pressure, shall be in accordance with These components shall begin at a point that includes a minimum coal column of 0.61 m (2 ft), at the point of connection of ductwork to the pulverizer, and at the seal air connections to the pulverizer system, and they shall end at the discharge of the pulverizer, external classifier, or exhauster All components of the pulverizer system shall be designed to withstand an internal explosion without rupture All components of the pulverizer system that are designed to be operated at no more than gauge pressure of 13.8 kpa (2 psi) with a design coal having P max of 10 bar-g or less shall be designed for a maximum allowable working pressure of 344 kpa (50 psi) for containment of possible explosion pressures.

242 For operating gauge pressures in excess of 13.8 kpa (2 psi) and design coal P max of 10 bar-g or less, the pulverizer system shall be designed to withstand an internal explosion pressure 3.4 times the absolute operating pressure Where the design coal P max is greater than 10 bar-g, the raw fuel feeder system shall be designed to withstand internal explosion pressures calculated in accordance with NFPA 68, Standard on Explosion Protection by Deflagration Venting, or NFPA 69, Standard on Explosion Prevention Systems. In these calculations, normal unobstructed openings shall be permitted to be considered in the calculation as mitigation of explosion pressures Equipment design strength shall incorporate the combined stresses from mechanical loading, operating, and explosion and implosion pressures plus an allowance for wear, which shall be determined by agreement between the manufacturer and the purchaser * Shock wave pressures shall be included in the design, based on their locations in the system Explosion vents shall not be used on the components of the air-swept pulverizer system Valves All valves in the pulverizer system from a point that includes a minimum coal column of 0.61 m (2 ft) to the point of consumption of the pulverized fuel shall have construction that is capable of withstanding pressures as defined in or , depending on the application These components shall include the following and any other pulverized fuel system valves: (1) Barrier valve (2) Dusttight valve (3) Check valve (4) Pressure/air lock (5) Raw fuel gate Interconnections. Valves at points of interconnection between pulverized fuel system components requiring different design pressures shall comply with the strength requirements of the lower pressure of the two Firing System Piping Arrangement Piping shall be arranged to prevent hazardous accumulation of fuel Where the air-fuel stream is directed into multiple pipes, the system shall divide the air-fuel mixture into design ratio among various pipes.

243 Pipe Velocities Positive means shall be provided to ensure that all pipe velocities are equal to or above the minimum velocity required for fuel transport and to prevent flashback from the burners Testing during initial start-up and retesting as appropriate shall be performed to verify that individual pipe velocities are adequate All piping system components shall be capable of being cleared of pulverized fuel using transport air The pulverized fuel piping from the outlet of the pulverizer system to the storage bin shall comply with Bend Radii Pulverized fuel piping shall provide smooth flow and have bend radii not less than one pipe diameter Wherever possible, radii in excess of one pipe diameter shall be used Flexible joints and split clamp couplings shall conform to through except that the junction of two sections shall be permitted to be sealed with flexible material There shall be no separation of the pipe joint in case of failure of the flexible material Positive mechanical connections shall be provided between the two sections to prevent serious misalignment or separation At operating temperatures encountered in the service of the equipment, piping materials shall satisfy the strength requirements of and shall comply with for allowable stresses Brittle materials having a plastic elongation of less than 8 percent prior to tensile rupture shall not be used for piping except as abrasion-resistant linings and where no credit is taken for the structural strength of the lining Piping support systems shall be designed and installed in accordance with Chapter 2, Part 5, of ASME B31.1, Power Piping, so that combined stresses will not be in excess of those specified in Pipe that is lined with abrasion-resistant material shall have casing thickness and flange size that is designed for the strength requirements in with no required allowance for wear Prior to initial operation or after piping system renovation, an in-service leak test shall be performed in accordance with the following procedure: (1) The system shall be gradually brought up to operating pressure and temperature.

244 (2) The system shall be held continuously at the conditions described in (1) for 10 minutes. (3) All joints and connections shall be examined for leakage. (4) The system shall show no visual evidence of weeping or leakage Valves Barrier valves, as shown in Figure (a) and Figure (c) through Figure (h), shall be provided in the piping between the pulverized fuel feeders and the burners of a storage indirect-fired system that is connected to one or more burners of a suction furnace A dusttight valve, as shown in Figure (b), shall be installed in each burner pipe between the pulverized fuel feeder and the burner for a storage indirect-fired system that is connected to one or more burners of a pressure furnace. These valves shall not be opened until the primary air pressure is established All valves in the firing system from a point that includes a minimum coal column of 0.61 m (2 ft) to the point of consumption of the pulverized fuel shall have construction that is capable of withstanding pressures as defined in or , depending on the application These components shall include the following and any other pulverized fuel system valves: (1) Barrier valve (2) Dusttight valve (3) Check valve (4) Pressure/air lock (5) Raw fuel gate Interconnections. Valves at points of interconnection between pulverized fuel system components requiring different design pressures shall comply with the strength requirements of the lower pressure of the two Primary Air Connections of Pressure Furnace Firing For pressure furnace firing, a dusttight valve, as shown in Figure (e), shall be installed between the forced draft system and the inlet for the primary air fan A minimum stop shall be provided on the primary air control damper to prevent its being completely closed unless the shutoff dampers in the burner pipes are closed Pulverized Fuel-Air Separation.

245 * In a pulverized fuel storage system that is not started and operated with an inert atmosphere in accordance with NFPA 69, Standard on Explosion Prevention Systems, the following equipment Cyclones and dust collectors shall meet the requirements of or shall be equipped with suitable vents in accordance with NFPA 68, Standard on Explosion Protection by Deflagration Venting:. (1) Cyclone (2) Dust collectors (3) Pulverized fuel bins The separated fuel shall be transported to storage bins for subsequent supply to the burners * All interconnected equipment in which a deflagration in one component could initiate a secondary deflagration in a connected component shall be equipped with explosion isolation or another method to prevent flame front propagation in accordance with NFPA 69, Standard on Explosion Prevention Systems Pulverized Fuel Transport System Piping and ducts used to transport pulverized fuel shall meet the requirements of or shall be equipped with suitable vents in accordance with NFPA 68, Standard on Explosion Protection by Deflagration Venting A pressure lock, as shown in Figure (a) and Figure (c) through Figure (h), shall be installed at each cyclone outlet if more than one cyclone is connected to a single pulverized fuel pump or if the cyclone is arranged for direct gravity discharge into the pulverized fuel bin. A pressure lock shall not be required at the cyclone outlet if only one cyclone is connected to the pulverized fuel pump Pulverized fuel lock hoppers shall be designed for 3.4 times the absolute operating pressure Pulverized fuel lock hoppers shall be designed to permit fuel discharge at an uninterrupted controlled rate Internal construction shall minimize accumulations Lock hoppers shall be equipped with high and low level fuel detectors Pulverized Fuel Storage A pressure lock, as shown in Figure (b), shall be installed at each fuel outlet of a pulverized fuel bin (if required) that is connected to a pressure furnace, to permit feeding of fuel into the burner lines at a higher pressure and to prevent the flow of primary air into the bin A pulverized fuel storage bin shall meet the requirements of or shall be equipped with suitable vents in accordance with NFPA 68, Standard on Explosion Protection by Deflagration Venting.

246 Pulverized fuel bins shall conform to strength requirements as specified in with exceptions as outlined in and These bins shall be designed to permit fuel discharge at an uninterrupted, controlled rate Internal construction shall minimize stagnant deposits Open-top bins shall not be used Provisions shall be made to prevent accumulation of flammable mixtures of air, fuel dust, and combustible gases within the bin Bins shall be equipped with high and low level fuel detectors Pulverized fuel lock hoppers shall be designed for 3.4 times the absolute operating pressure Pulverized fuel lock hoppers shall be designed to permit fuel discharge at an uninterrupted controlled rate Internal construction shall minimize accumulations Lock hoppers shall be equipped with high and low level fuel detectors Separated Air A check valve, as shown in Figure (c) through Figure (f) and Figure (h), shall be installed in each vent pipe connecting the cyclone or dust collector of a storage indirect-fired system to the primary air fan or to any portion of the furnace or stack of a suction furnace Venting Partial venting shall be used to control humidity in the pulverized fuel system, to minimize quantity of vented air or gas, or to conserve heat Total venting shall be used where there is no further use for the transport air or gas Both vent systems shall have the common requirements of through (A) through (F). (A) There shall be no venting to a pressure furnace. (B) Venting to a suction furnace shall be permitted when it is delivered to a zone where combustion is active and injection line velocities are maintained at least 50 percent above the maximum flame propagation rate of the fuel. (C) Venting to a stack, flue, or breeching shall be permitted when it is done to a zone where the temperature does not exceed two-thirds of the ignition temperature of the fuel and the design of the entire vent system is such that there will be no hazardous accumulation of combustible fuel dust.

247 (D) Venting to the primary air fan shall be permitted when the primary air fan is operating and the following conditions are met: (1) A means is provided to prevent reverse flow. (2) The primary air system can handle the total amount of air. (3) The primary air fan is discharging to a zone of active combustion. (E) When venting to the atmosphere, the vented air or gas shall be sufficiently clean of combustible material so as not to create fire or an explosion hazard. The vented air or gas shall not interfere with the proper operation of other systems within the area. (F) Check valves, where required, shall be located near the source of possible reverse flow into the system When the vented air from the cyclone, as shown in Figure (a), is discharged to the atmosphere, the vent shall discharge at a height above the building roof to prevent accumulations on the roof When the vented air is discharged into the stack, flue, or breeching, the connection shall be made at a point where the pressure is less than that of the room in which the pulverizer is located, and each vent line shall have a check valve that opens in the direction of the flow Vent connections shall be located downstream of the recirculated gas inlet connection in such a manner that any combustible dust that is carried by the vented air cannot be entrained in the recirculated gas for possible introduction into a zone of high furnace temperature The separated fuel shall be transported to storage bins for subsequent supply to the burners Valve Requirements Barrier valves, as shown in Figure (a) and Figure (c) through Figure (h), shall be provided in the piping between the pulverized fuel feeders and the burners of a storage system that is connected to one or more burners of a suction furnace A check valve, as shown in Figure (c) through Figure (f) and Figure (h), shall be installed in each vent pipe connecting the cyclone or dust collector of a storage system to the primary air fan or to any portion of the furnace or stack of a suction furnace A dusttight valve, as shown in Figure (b), shall be installed in each burner pipe between the pulverized fuel feeder and the burner for a storage system that is connected to one or more burners of a pressure furnace. These valves shall not be opened until the primary air pressure is established A pressure lock, as shown in Figure (b), shall be installed at each fuel outlet of a pulverized fuel bin (if required) that is connected to a pressure furnace, to permit

248 feeding of fuel into the burner lines at a higher pressure and to prevent the flow of primary air into the bin A pressure lock, as shown in Figure (a) and Figure (c) through Figure (h), shall be installed at each cyclone outlet if more than one cyclone is connected to a single pulverized fuel pump or if the cyclone is arranged for direct gravity discharge into the pulverized fuel bin. A pressure lock shall not be required at the cyclone outlet if only one cyclone is connected to the pulverized fuel pump Primary Air Connections of Pressure Furnace Firing For pressure furnace firing, a dusttight valve, as shown in Figure (e), shall be installed between the forced draft system and the inlet for the primary air fan A minimum stop shall be provided on the primary air control damper to prevent its being completely closed unless the shutoff dampers in the burner pipes are closed Venting Partial venting shall be used to control humidity in the pulverized fuel system, to minimize quantity of vented air or gas, or to conserve heat Total venting shall be used where there is no further use for the transport air or gas Both vent systems shall have the common requirements of (A) through (F). (A) There shall be no venting to a pressure furnace. (B) Venting to a suction furnace shall be permitted when it is delivered to a zone where combustion is active and injection line velocities are maintained at least 50 percent above the maximum flame propagation rate of the fuel. (C) Venting to a stack, flue, or breeching shall be permitted when it is done to a zone where the temperature does not exceed two-thirds of the ignition temperature of the fuel and the design of the entire vent system is such that there will be no hazardous accumulation of combustible fuel dust. (D) Venting to the primary air fan shall be permitted when the primary air fan is operating and the following conditions are met: (1) A means is provided to prevent reverse flow. (2) The primary air system can handle the total amount of air. (3) The primary air fan is discharging to a zone of active combustion. (E) When venting to the atmosphere, the vented air or gas shall be sufficiently clean of combustible material so as not to create fire or an explosion hazard. The vented air or gas shall not interfere with the proper operation of other systems within the area.

249 (F) Check valves, where required, shall be located near the source of possible reverse flow into the system When the vented air from the cyclone, as shown in Figure (a), is discharged to the atmosphere, the vent shall discharge at a height above the building roof to prevent accumulations on the roof When the vented air is discharged into the stack, flue, or breeching, the connection shall be made at a point where the pressure is less than that of the room in which the pulverizer is located, and each vent line shall have a check valve that opens in the direction of the flow Vent connections shall be located downstream of the recirculated gas inlet connection in such a manner that any combustible dust that is carried by the vented air cannot be entrained in the recirculated gas for possible introduction into a zone of high furnace temperature Pulverizer System Component Design Requirements Strength of Equipment All components of the pulverized fuel system as described in that are designed to be operated at no more than gauge pressure of 13.8 kpa (2 psi) shall be designed to withstand an internal explosion gauge pressure of 344 kpa (50 psi) for containment of possible explosion pressures For operating gauge pressures in excess of 13.8 kpa (2 psi), the equipment as described in shall be designed to withstand an internal explosion pressure 3.4 times the absolute operating pressure Equipment design strength shall incorporate the combined stresses from mechanical loading, operating, and explosion and implosion pressures plus an allowance for wear, which shall be determined by agreement between the manufacturer and the purchaser * Shock wave pressures shall be included in the design, based on their locations in the system Components The components falling within the requirements of through for a direct-fired system shall begin at a point that includes a minimum coal column of is 0.61 m (2 ft) above the inlet of the raw fuel feeder, at the point of connection of ductwork to the pulverizer, and at the seal air connections to the pulverizer system, and they shall end at the discharge of the pulverizer, external classifier, or exhauster These components shall include the following and any associated devices: (1) Raw fuel feeding devices, discharge hoppers, and feed pipes to the pulverizer (2) All parts of the pulverizer that are required for containment of internal pressure (3) Exhauster and connecting piping from the pulverizer

250 (4) External classifiers and connecting piping from the pulverizer (5) Foreign material collecting hoppers that are connected to the pulverizer The raw fuel bunker and mechanical components, including but not limited to seals, gears, bearings, shafts, and drives, shall not be required to meet these requirements Explosion vents shall not be used on any component of the system that is described in * All ductwork, from the hot and tempering air supply ducts to individual pulverizers, including damper frames, expansion joints, supports, and hot primary air fans, shall be designed to contain the test block capability of the pulverizer air supply fan Inert Atmosphere If an pulverized fuel storage indirect-fired system is started and operated with an inert atmosphere in all parts of the system in accordance with NFPA 69, Standard on Explosion Prevention Systems, the strength requirements of shall not apply Any component of the system that is started and operated with an inert atmosphere shall not be required to comply with the strength requirements of Auxiliary Systems Emergency Inerting System Pulverizers and indirect-fired systems shall be equipped with an inerting system that is capable of maintaining an inert atmosphere as required to meet the provisions of (See also NFPA 69, Standard on Explosion Prevention Systems.) Provisions shall be made for verification of flow of inerting media when the system is activated Where an inerting system is required in accordance with , it shall be permanently installed and equipped with connections, which shall be a minimum of 25.4 mm (1 in.) in diameter Injection shall be controlled by readily operable valves or dampers. (See NFPA 69, Standard on Explosion Prevention Systems.) Operation of these valves shall be accomplished at a location that is remote from the pulverized fuel system Where these valves are manually operated, they shall be readily accessible Where these valves are manually operated, they shall be identified by a sign in block letters of not less than 51 mm (2 in.) in height on a background of contrasting color to the letters Fire-Extinguishing System Connections.

251 Pulverizers and pulverized fuel collecting systems shall be equipped with connections for fire extinguishing These connections shall be at least 25 mm (1 in.) in diameter and shall be adequate to pass the amount of required extinguishing material Provisions shall be made for verification of flow of fire-extinguishing media when the system is activated Safety Interlock Systems The safety interlocks required in this section shall be coordinated with the boiler, furnace, or other related devices to which the pulverized fuel system is connected Permissive Sequential-Starting Interlocks Permissive sequential-starting interlocks for pulverized fuel storage indirect-fired systems shall be arranged so that the system components can be started only in the following sequence: (1) Start pulverized fuel pump or conveyor. (2) Start cyclone and dust collector pressure locks. (3) Start vent fan. (4) Start pulverizer exhauster or air fan. (5) Start pulverizer. (6) Start raw fuel feeder The actions of (4) and (5) shall be permitted to be simultaneous Interlocks for pulverizers of storage indirect-fired systems shall be arranged to trip as follows: (1) The full pulverized fuel bin shall trip the fuel pump or conveyor and the raw fuel feeder. (2) Failure of the fuel pump or conveyor shall trip the vent fan on the cyclone or dust collector and pressure locks upstream of the fuel pump or conveyor. (3) Failure of the vent fan shall trip the pulverizer exhauster or air fan. (4) Failure of the pulverizer exhauster or air fan shall trip the raw fuel feeder. (5) Failure of the pulverizer shall trip the raw fuel feeder For pressure furnaces that are firing from storage indirect-fired or semistorage semi-direct-fired systems, the dusttight valve in the burner pipe that is after the pulverized fuel feeder shall be interlocked so that it cannot be opened unless the dusttight damper in the primary air supply is open.

252 Noninert Atmosphere A pulverized fuel storage system that is not started and operated with an inert atmosphere in accordance with NFPA 69, Standard on Explosion Prevention Systems, shall meet the requirements of The components falling within these requirements shall be those described in , plus any or all of the following that are included in the system: (1) Lock hoppers (2) Circulating fans (3) Transport systems (4) Pulverized fuel feeders (5) Primary air fans handling fuel-laden air (6) Vent fans if not located downstream of a dust collector that is vented in accordance with * In a pulverized fuel storage system that is not started and operated with an inert atmosphere in accordance with NFPA 69, Standard on Explosion Prevention Systems, the following equipment shall meet the requirements of or shall be equipped with suitable explosion vents in accordance with NFPA 68, Standard on Explosion Protection by Deflagration Venting: (1) Cyclone (2) Dust collectors (3) Pulverized fuel bins Explosion vents shall not be used on the feeder or pulverizer of any system Piping General For systems that are normally operated at a gauge pressure no more than 13.8 kpa (2 psi), the pulverized fuel piping from the outlet of the equipment, as defined in and , to the pulverized fuel burner or storage bin shall comply with Systems that are operated at a gauge pressure greater than 13.8 kpa (2 psi) shall be designed to withstand an internal explosion of 3.4 times the absolute operating pressure Wear There shall be an allowance for wear in excess of the strength requirements of

253 Elbows are especially vulnerable to wear, but all parts of the system shall be designed for wear as determined by agreement between the manufacturer and the purchaser Bend Radii Pulverized fuel piping shall provide smooth flow and have bend radii not less than one pipe diameter Wherever possible, radii in excess of one pipe diameter shall be used Flexible joints and split clamp couplings shall conform to except that the junction of two sections shall be permitted to be sealed with flexible material There shall be no separation of the pipe joint in case of failure of the flexible material Positive mechanical connections shall be provided between the two sections to prevent serious misalignment or separation At operating temperatures encountered in the service of the equipment, piping materials shall satisfy the strength requirements of and shall comply with for allowable stresses Brittle materials having a plastic elongation of less than 8 percent prior to tensile rupture shall not be used for piping except as abrasion-resistant linings and where no credit is taken for the structural strength of the lining Piping support systems shall be designed and installed in accordance with Chapter 2, Part 5, of ASME B31.1, Power Piping, so that combined stresses will not be in excess of those specified in Pipe that is lined with abrasion-resistant material shall have casing thickness and flange size that is designed for the strength requirements in with no required allowance for wear Prior to initial operation or after piping system renovation, an in-service leak test shall be performed in accordance with the following procedure: (1) The system shall be gradually brought up to operating pressure and temperature. (2) The system shall be held continuously at the conditions described in (1) for 10 minutes. (3) All joints and connections shall be examined for leakage. (4) The system shall show no visual evidence of weeping or leakage Valves All valves in the pulverized fuel system from a point within 0.61 m (2 ft) above the inlet of the raw fuel feeder to the point of consumption of the pulverized fuel shall have

254 construction that is capable of withstanding pressures as defined in , , or , depending on the application These components shall include the following and any other pulverized fuel system valves: (1) Barrier valve (2) Dusttight valve (3) Check valve (4) Pressure/air lock (5) Raw fuel gate Interconnections. Valves at points of interconnection between pulverized fuel system components requiring different design pressures shall comply with the strength requirements of the lower pressure of the two Bunker and Hopper Designs The raw fuel bunker structural material shall be made of noncombustible material and shall be designed to provide the following mass flow and self-cleaning flow characteristics: (1) An uninterrupted flow of fuel being handled at a controlled rate (2) A flow pattern in which arching and ratholing (piping) are avoided The bunker outlet feeder(s) shall be coordinated with the bunker to avoid the probability that incorrect feeder selection will result in altering the bunker flow characteristics as specified in (1) or (2) Provisions shall be made to prevent the accumulation of flammable mixtures of air, fuel dust, and combustible gases within the bunker Pulverized fuel bins shall conform to strength requirements as specified in with exceptions as outlined in and These bins shall be designed to permit fuel discharge at an uninterrupted, controlled rate Internal construction shall minimize stagnant deposits Open-top bins shall not be used Provisions shall be made to prevent accumulation of flammable mixtures of air, fuel dust, and combustible gases within the bin Bins shall be equipped with high and low level fuel detectors Pulverized fuel lock hoppers shall be designed for 3.4 times the absolute operating pressure.

255 Pulverized fuel lock hoppers shall be designed to permit fuel discharge at an uninterrupted controlled rate Internal construction shall minimize accumulations Lock hoppers shall be equipped with high and low level fuel detectors Construction Materials for Pressure Containment Materials that are used to meet strength requirements shall be ferrous materials and shall satisfy the strength requirements of at design operating temperatures If made of steel or other ductile metals, the allowable stress values shall be determined as specified in through Tension. The maximum allowable direct (i.e., membrane) stress shall not exceed the lesser of ¼ the ultimate strength or 5 8 the yield strength of the material Combined Bending and Membrane Stress (Where Bending Stresses Are Not Self-Limiting). The maximum allowable value of combined bending and membrane stress shall not exceed the lesser of the yield strength or ½ the ultimate strength of the material Combined Bending and Membrane Stress (Where Bending Stresses Are Self- Limiting). The maximum allowable values of combined self-limiting and non-self-limiting bending stresses plus membrane stress shall not exceed the ultimate strength of the material Compressive Stress. For components in which compressive stresses occur, in addition to the requirements of through , the critical buckling stress shall be taken into account Fatigue Analysis. On components subject to cyclic loading, fatigue analysis shall be made to guard against possible fatigue failures. Both mechanical and thermal loading shall be analyzed If made of cast iron or other nonductile material, the allowable stress shall not exceed ¼ the ultimate strength of the material for all parts When cast iron or other nonductile material is used for flat areas exceeding m 2 (1 ft 2 ), the surface shall be strengthened by ribbing or other means An evaluation of the possibility of buckling and fatigue failures shall be made To ensure casting quality, nondestructive examination shall be made to detect significant defects at locations of high stress, at abrupt changes of section, and at sharp angles The choice of such a quality assurance program shall be the responsibility of the designer The justification of new materials or improved analytical methods shall be the responsibility of the designer.

256 If such materials and methods are used for the design of pulverized fuel system components, they shall meet the strength requirements of and The materials that are used shall be capable of withstanding the conditions that could occur during abnormal incidents, such as pulverized fuel fires Electrical Equipment All electrical equipment and wiring shall conform to NFPA 70, National Electrical Code Locations where completely dusttight pulverized fuel systems are installed in compliance with this code shall not be considered a hazardous location for electrical equipment as defined in NFPA 70, National Electrical Code Inerting System Pulverizers and pulverized fuel storage systems shall be equipped with an inerting system that is capable of maintaining an inert atmosphere as required to meet the provisions of (See also NFPA 69, Standard on Explosion Prevention Systems.) Provisions shall be made for verification of flow of inerting media when the system is activated Fire-Extinguishing System Connections Pulverizers and pulverized fuel collecting systems shall be equipped with connections for fire extinguishing These connections shall be at least 25 mm (1 in.) in diameter and shall be adequate to pass the amount of required extinguishing material Provisions shall be made for verification of flow of fire-extinguishing media when the system is activated Safety Interlock Systems The safety interlocks required in this section shall be coordinated with the boiler, furnace, or other related devices to which the pulverized fuel system is connected Permissive Sequential-Starting Interlocks Permissive sequential-starting interlocks for direct-fired systems shall be arranged so that, after furnace or other connected apparatus interlocks have been satisfied, the pulverizer can be started only in the following sequence: (1) Start ignition system in accordance with Chapter 6. (2) Start primary air fan or exhauster. (3) Establish minimum airflow.

257 (4) Start pulverizer. (5) Start raw fuel feeder The actions of (2) and (4) shall be permitted to be simultaneous Trip Sequence of Interlocks Interlocks for direct-fired pulverized fuel systems shall be arranged to trip in the following sequence: (1) Failure of primary airflow to below manufacturer's minimum shall trip the pulverizer and burner shutoff valve or equivalent and the feeder. The manufacturer's requirements regarding the burner's shutoff valve operation shall be followed. (2) Failure of pulverizer shall trip the feeder and primary airflow. (3) Closure of all fuel line valves shall trip the pulverizer, primary airflow, and raw fuel feed. (4) Failure of the feeder shall initiate an alarm; restarting of the feeder shall be blocked until feeder start-up conditions are re-established Means to indicate loss of fuel feed to the pulverizer or fuel input to the furnace shall be installed Permissive Sequential-Starting Interlocks Permissive sequential-starting interlocks for pulverized fuel storage systems shall be arranged so that the system components can be started only in the following sequence: (1) Start pulverized fuel pump or conveyor. (2) Start cyclone and dust collector pressure locks. (3) Start vent fan. (4) Start pulverizer exhauster or air fan. (5) Start pulverizer. (6) Start raw fuel feeder The actions of (4) and (5) shall be permitted to be simultaneous Interlocks for pulverizers of storage systems shall be arranged to trip as follows: (1) The full pulverized fuel bin shall trip the fuel pump or conveyor and the raw fuel feeder. (2) Failure of the fuel pump or conveyor shall trip the vent fan on the cyclone or dust collector and pressure locks upstream of the fuel pump or conveyor. (3) Failure of the vent fan shall trip the pulverizer exhauster or air fan. (4) Failure of the pulverizer exhauster or air fan shall trip the raw fuel feeder.

258 (5) Failure of the pulverizer shall trip the raw fuel feeder For pressure furnaces that are firing from storage or semistorage systems, the dusttight valve in the burner pipe that is after the pulverized fuel feeder shall be interlocked so that it cannot be opened unless the dusttight damper in the primary air supply is open Operation Operation of All Pulverized Fuel Systems Preparation for Starting conditions: Preparation for every start-up shall include checks for the following (1) The pulverizer system sealing air, if required, is in service. (2) Energy is supplied to the control system and to the safety interlocks. (3) All pulverizer system gates, valves, and dampers are in start-up positions After maintenance or outage, the following inspections and checks shall be made by the owner/operator or the owner s/operator s designated representative: (1) Pulverizers, ducts, and fuel piping are in good repair and free from foreign material. (2) Pulverizers, ducts, and fuel piping are evacuated by all personnel, all access and inspection doors are closed, and all personnel protection devices are reinstalled. (3) All pulverizer air or flue gas dampers are operated through the full operating range. (4) Pulverizers, feeders, controls, and associated equipment are in a condition ready for service. (5) A complete functional check is made of all safety interlocks Operation of Direct-Fired Systems * Starting Sequence. The starting sequence shall consist of all of the following steps: (1) Start all necessary light-off equipment in accordance with Chapter 6 requirements. (2) Open the pulverizer tempering air damper. (3) Start the primary air fan or exhauster, if driven separately from the pulverizer. (4) Open the primary airflow control damper to a setting that provides a burner line transport velocity greater than or equal to the established minimum. (5) Open the pulverizer burner line valves. (6) Start the pulverizer.

259 (7) Open the pulverizer hot air damper and maintain pulverizer outlet temperature within the specified range (as dictated by the system designer or field tests). (8) Start the raw fuel feeder. (9) Place the pulverizer outlet temperature, primary airflow, and raw fuel feed controls on automatic It shall be permitted to vary the sequence of the steps in (2) through (9) as recommended by the system designer * Normal Operation The output of the pulverizer shall be regulated by adjusting its fuel and air supplies in accordance with the manufacturer's procedures or as determined by field tests Individual Burner Shutoff Valves Individual burner shutoff valves, if provided, shall be wide open or completely closed Individual burner shutoff valves shall not be placed at intermediate settings * Burner line transport velocities shall be maintained at or above minimum for all pulverizer loading conditions A pulverizer shall not be operated below its minimum air or fuel stop setting * Normal Shutdown. The pulverizer shutdown sequence shall consist of all of the following steps: (1) Reduce pulverizer output and establish required combustion system conditions for shutdown as required in Chapter 6. (2) Reduce the hot air and increase the cold air to cool the pulverizer to a predetermined minimum outlet temperature as recommended by the system designer or as determined by test. (3) When the pulverizer is cooled, stop the feeder and continue operation of the pulverizer with the minimum established airflow to remove all fuel from the pulverizer and burner lines. Maintain minimum outlet temperature (typically requires shutoff of hot air supply when feeder is stopped). (4) Shut the pulverizer down after a predetermined time as required to empty the pulverizer as determined by field tests. (5) Position burner line shutoff valves in accordance with the manufacturer's instructions. (6) Stop primary air flow.

260 It shall be permitted to vary the sequence of the steps in (1) through (6) as recommended by the system designer Operation of Storage Indirect-Fired Systems Operation of Fuel-Burning Equipment Starting Sequence. The starting sequence shall be as follows: (1) Coordinate the fuel-burning portion with the furnace in accordance with Chapter 6. (2) Start the primary air fan(s). (3) Open all burner and primary air shutoff valves for the burners to be started. (4) Open the pulverized fuel gate and start the pulverized fuel feeder for these burners Normal Operation Individual Burner Valves. (A) (B) Individual burner valves shall be wide open or completely closed. Individual burner valves shall not be placed at intermediate settings Fuel flow shall be controlled by adjusting the pulverized fuel feeder speed Primary airflow shall be maintained at all times to prevent settling of coal dust in burner pipes Normal Shutdown. The shutdown sequence shall be as follows and in accordance with Chapter 6: (1) Establish the required combustion system conditions for shutdown. (2) Stop the pulverized fuel feeder. (3) When the burner flame is extinguished, close the burner and primary air shutoff valves, unless primary air valves supply air to all burners during operation. (4) Stop the primary air fan after the last burner that is served by that fan is shut down Operation of Pulverizing Equipment of Storage Indirect-Fired Systems Starting Sequence The basic principle that shall be followed is that of starting equipment in sequence from the storage bin upstream toward the point of pulverizer air supply and then finally the raw fuel supply, as shown in Figure (a) through Figure (h) The starting sequence shall be as follows: (1) Start the pulverized fuel pump or conveyor, if provided.

261 (2) Start the cyclone pressure lock, if provided. (3) Start the cyclone or dust collector vent fan or exhauster and/or the primary air fan and open the burner and primary air shutoff valves if used to convey the vent stream and burners are not in service, in accordance with (4) Start the pulverizer exhauster or fan and adjust the control dampers to obtain proper air flow and temperature. (5) Start the pulverizer. (6) Start the raw fuel feeder. (7) Readjust the control damper(s) to obtain required pulverizer air-fuel outlet temperature and airflow Normal Shutdown. The shutdown sequence shall be as follows: (1) Close the hot air damper and open the cold air damper or flue gas damper to cool down the pulverizer. (2) Stop the raw fuel feeder. (3) Operate the pulverizer for a predetermined time as required to empty the pulverizer of fuel and make it cool. Stop the pulverizer. (4) Stop the pulverizer exhauster or fan. (5) Stop the cyclone and dust collector vent fan or exhauster and/or the primary air fan if used to convey the vent stream and all burners are shut down. (6) Stop cyclone pressure lock. (7) Stop pulverized fuel pump or conveyor Abnormal Pulverizer System Conditions When a fire is suspected in the pulverizer system or abnormal operating conditions are encountered, all personnel shall be cleared from the area near the pulverizer, primary air duct, burner pipes, burners and feeder, or other pulverized fuel system components before the operating conditions are changed Pulverizer Pulverized Fuel System Tripping Inerting A pulverizer in a direct-fired pulverized fuel system that is tripped under load shall be inerted and maintained under an inert atmosphere until confirmation that no burning or smoldering fuel exists in the pulverizer or the fuel is removed The following components in an indirect-fired pulverized fuel system that is tripped under load shall be inerted in a pre-defined time as established by the system designer:

262 (1) Pulverizer (2) (3) (4) External classifier Fuel-air separators [cyclone(s), bag house(s), or electrostatic precipitator(s)]. Pulverized fuel bin(s) Inerting Procedure. (A) The inerting procedure shall be established by the pulverizer equipment manufacturer and the purchaser. (B) The pulverizer equipment manufacturer and purchaser shall consider fuel characteristics, the pulverizer temperature and size, and arrangement of the pulverizer Inerting media shall be selected from, but not limited to, the following: (1) Carbon dioxide (2) Steam (3) Nitrogen Fuel-Clearing Procedures For pulverizers that are tripped and inerted while containing a charge of fuel in accordance with , one of the following procedures shall be used to clear fuel from the pulverizers and sweep the transport lines clean as soon as possible after the trip and there is confirmation that there is no burning or smoldering fuel: (1) Clear one pulverizer at a time under inert conditions into the furnace using the following procedure: (a) Isolate from the furnace all shutdown or tripped pulverizers. (b) Start up one pulverizer in accordance with the principles and sequences listed in (1) through (9). (c) Continue to operate the pulverizer until empty and in normal condition for shutdown. When the operating pulverizer is empty of fuel, proceed to another tripped and inerted pulverizer and repeat the procedure until all are cleared of fuel. Exception: An exception to (1)(c) is to restart the feeder and return the pulverizer to normal operation if furnace conditions allow such operation. (2) Clear one pulverizer at a time under inert conditions through the pyrites removal system using the following procedure: (a) Remove fuel through the pyrites removal system using operation of the pulverizer motor as necessary.

263 (b) Start the pulverizer with an inert medium, using the starting sequences in (1) through (9) Burning Fuel in Out-of-Service Pulverizer. (A) In the event that there are indications of burning or smoldering fuel in an out-of-service pulverizer, the pulverizer shall not be restarted under the normal procedure. (B) Fire-extinguishing procedures shall be followed, or removal of residual fuel shall be accomplished under inert conditions by taking one of the following steps: (1) Remove fuel through the pyrites removal system. When this procedure is followed, the pulverizer shall be opened and inspected by the owner/operator or the owner s/operator s designated representative prior to restarting. (2) Start the pulverizer with an inert medium, using the starting sequences in (1) through (9). (C) Due to the danger of an explosion when they are being opened and cleaned, pulverizers shall not be cleaned manually until they and their contents have been cooled to ambient temperature. (D) The procedures of shall be followed Fires in Pulverized Fuel Systems Indication of a fire in any part of a pulverized fuel system is a serious condition and shall be dealt with promptly Extinguishing media shall be water or inert solids or shall be in accordance with The following procedures for fighting fires shall be used, with modifications for specific systems, specific locations of fire, or requirements of the equipment manufacturer: (1) If sufficient flow capacity of inerting media is provided (at least 50 percent by volume of the minimum primary airflow for the system), inert the pulverizer air-fuel flow, shut off the fuel feed, empty the pulverizer of fuel, and shut down and isolate the pulverizer. (2) Stop the primary airflow, trip the pulverizer and feeder, isolate the system, inert, and proceed as follows: (a) Do not disturb any accumulation of dust in the pulverizing equipment. (b) Do not open any access doors to the pulverizer until the fire is extinguished and all temperatures have returned to ambient. (c) After isolation of the pulverizer is verified, follow the procedures as outlined in and

264 (3) Extinguish a fire that is detected in an operating low storage pulverizer by shutting off the hot air, increasing the raw fuel feed as much as possible without overloading the pulverizer, and continuing to operate with tempering air. (4) Introduce water into the raw fuel or tempering air stream, or both, and proceed as follows: (a) The water must be added in such quantities and at such locations as not to cause hang-up or interruption of raw fuel feed or to stir up any deposit of combustible material. (b) When all evidence of fire has disappeared, shut off the water, trip the pulverizer, isolate, and inert When fires are detected in other parts of a direct-fired system, such as burner lines, the procedures as outlined in (1), (2), or (3) shall be followed When fires are detected in storage indirect-fired system components, including but not limited to cyclones, dust collectors, and pulverized fuel bins, the affected components shall be isolated and inerted If fire is detected in an out-of-service pulverizer, it shall be kept out of service and isolated All air supply to the pulverizer shall be shut off Access doors to a pulverizer shall not be opened until the fire is extinguished by water or other extinguishing media and all temperatures have returned to ambient Pulverizing equipment shall be inspected internally by the owner/operator or the owner s/operator s designated representative following fires in pulverizing systems All coke formations and other accumulations shall be removed to reduce the potential for future fires If the pulverizer is wet, it shall be dried In no case shall a compressed air jet be used All components shall be inspected, and damaged items, including but not limited to gaskets, seals, lubricants, and liners, shall be replaced. 9.7 Special Systems Introduction. Specific systems, as defined in this section, shall meet the specific requirements of this section. (For general design, operating, and safety requirements of these systems, see Sections 9.4 and 9.5.) Semi-Direct-FiredFiring System Description. This system, as shown in Figure (a) and Figure (b), shall consist of an air-swept pulverizer located near the point of use.

265 ****INSERT FIGURE HERE**** FIGURE (a) Semi-Direct-FiredFiring Pulverized Fuel System for a Suction Furnace. ****INSERT FIGURE HERE**** FIGURE (b) Semi-Direct-FiredFiring Pulverized Fuel System for a Pressurized Furnace The fuel shall be separated from the air in a cyclone or other type of dust collector Fuel shall discharge from the cyclone through a rotary valve and shall be picked up by air from a primary air fan and blown into the furnace The primary air fan shall take suction from the pulverizer air fan or from other sources If the primary air fan does not utilize all of the pulverizer air, a vent fan shall be required System Arrangement. This system shall be permitted to include the following special equipment: (1) Cyclone separator or other type of dust collector (2) Pressure lock (3) Primary air fan (4) Vent fan and dust collector, if required (5) Pulverized fuel pickup Valve Requirements A barrier valve and a dusttight valve shall be installed between each fuel pickup point and the burner for a suction furnace that can be fired by other fuels Two dusttight valves shall be installed between the fuel pickup point and the burner for a pressurized furnace if the furnace can be fired by other fuels One of the valves described in and shall be quick closing Valves shall not be required between the pulverizer and the cyclone Isolation Requirements. Isolation requirements shall be in accordance with Operation.

266 Starting Sequence. The starting sequence shall be as follows: (1) Start up all necessary combustion system auxiliaries in the proper sequence. (2) Start the forced draft fan (for the pressure furnace only). (3) Start the primary air fan. (4) Open all valves in lines to burners to be started, including barrier valves and dusttight valves. (5) Adjust the primary airflow to the desired value, at least sufficient to provide minimum burner line velocity. (6) Start pressure locks. (7) Start the pulverizer air fan. (8) Start the pulverizer. (9) Start the vent fan, if required. (10) Start the raw fuel feeder. (11) Adjust the dampers and controls as in (9) Normal Operation. The procedures of shall be followed Normal Shutdown. The normal shutdown procedure shall be as follows: (1) Follow the procedures of (2) When the pulverizer is empty and cool, stop the pulverizer and the pulverizer air fan or exhauster. (3) Stop the pressure locks. (4) Stop the vent fan. (5) Stop the primary air fan Interlocking. Interlocking shall be as outlined in Pulverized Fuel System for Blast Furnace Injection Description. This system, as shown in Figure , shall consist of an airswept pulverizer. ****INSERT FIGURE HERE**** FIGURE Blast Furnace Pulverized Fuel Injection System The fuel shall be separated from the air in a cyclone or other type of dust collector.

267 Fuel shall discharge from the cyclone through a pressure lock valve and be collected, stored, and batch-pressurized to a pressure that is higher than the blast furnace pressure The pressurized fuel shall then be transported and distributed to the furnace tuyeres This system shall have the following three major subsystems: (1) Fuel grinding and collecting system (2) Inert gas, pressurized fuel, storage, and feeding system (3) Pulverized fuel transportation and distribution system System Arrangement The pulverizer and pulverized fuel-collecting, fuel-pressurizing, and fuelfeeding equipment shall be located remotely from the blast furnace unless other design requirements locate it close to the furnace The distribution system shall be located close to the blast furnace The pulverizer fan shall be located ahead of the air heater and the pulverizer, between the air heater and the pulverizer, at the pulverizer outlet, or at the cyclone or dust collector vent This system shall include the following special equipment: (1) Pulverizer air heater (2) Cyclone separator or other type of dust collector (3) Cyclone pressure lock (4) Pulverized-fuel bin (5) Pulverized-fuel feed tanks (6) Pressuretight isolation valves (7) Injection air system (8) Inert gas system (9) Fuel injection lances (10) Flow control of air or flue gas (11) Vent dust collector Valve Requirements.

268 Pressure locks shall be installed at the pulverized fuel discharge of the cyclone separator or vent dust collector return lines Dusttight Valves Special dusttight valves shall be installed at each fuel outlet of the pulverized fuel bin, at the fuel discharge outlet of each feed tank, and at each fuel outlet of the pulverized fuel distributors These valves shall be tight at a pressure that is 1.5 times the required pressure in the feed tanks Isolation Requirements. Isolation damper(s) shall be provided upstream of the pulverizer and at the discharge of the cyclone separator to permit inerting in this system Operation Operating procedures for handling pulverized fuel being injected to the blast furnace shall be established to avoid fires and explosions in the pulverized fuel injection system Operation of Fuel Pulverizing Equipment. The principles and procedures of shall apply to this storage-grinding system Operation of fuel injection equipment shall be as follows: (1) Ascertain that the blast furnace is in service before starting the pulverized fuel injection system. (2) Start the inert gas source. (3) Start the injection air system blower or compressor and pressurize the injection line to the distributor. (4) Pressurize the filled pulverized fuel feed tank with inert gas. (5) Open the dusttight valves in lines leaving the distributors. (6) Establish transport airflow. (7) Open the discharge dusttight valves from the pulverized fuel feed tank Inert gas shall be used to fluidize and pressurize the feed tank system Pulverized fuel flow shall be controlled by regulating the pressure drop across the system Normal Shutdown The shutdown sequence shall be as follows: (1) Empty the fuel bin and feed tanks of pulverized fuel. (2) Purge the injection and distribution system.

269 (3) Close the distributor dusttight valves If all pulverized fuel cannot be removed from the system, inert gas shall be provided for the feed hoppers and pulverized fuel bin when the system is idle Interlocking. In addition to the interlocking requirements of , the following shall be included: (1) Failure of the pulverizer airflow trips the separately fired air heater. (2) Failure of the cyclone separator or other type of dust collector pressure lock trips the raw coal feeder. (3) Power failure closes all valves that are required to isolate the system Direct-FiredFiring System for Rotary Kilns. This system is a form of direct firing as described in and shown in Figure (a) and Figure (b). The only special equipment is an optional dust collector with a pressure lock for cleaning hot air or gas. ****INSERT FIGURE HERE**** FIGURE (a) Direct-Fired Pulverized Fuel Systems for Rotary Kilns with Pressure Pulverizer. ****INSERT FIGURE HERE**** FIGURE (b) Direct-Fired Pulverized Fuel Systems for Rotary Kilns with Suction Pulverizer Isolation Requirements When a bypass air system is used, a bypass control damper shall be installed A tempering damper shall be installed near the kiln hood to protect the hot gas duct Operation Starting Sequence. The starting sequence shall be as follows: (1) Start the pressure lock. (2) Start the primary air fan or exhauster. (3) Start the air heaters, if furnished. (4) Start the pulverizer. (5) Start the raw fuel feeder.

270 (6) Adjust the primary air and fuel to the desired value Normal Operation. Normal operation shall be as described in Normal Shutdown. The normal shutdown procedure shall be as follows: (1) Shut off the hot air. (2) When the pulverizer is cool, stop the raw fuel feeder. (3) When the pulverizer is empty, stop the pulverizer. (4) Stop the primary air fan or exhauster. (5) Stop the pressure lock Interlocking. Interlocking shall be as described in

271 Page 499 of 595 The chapter was restructured to separate requirements for direct-fired and indirect-fired systems. The requirements for indirect-fired systems were greatly expanded and clarified so that the chapter is easier to apply to the unique hazards related to these types of systems. The direct-fired and indirect-fired systems were further divided into their major subsystems. As a result, the terminology was reviewed to ensure that direct-fired and indirect-fired are used consistently throughout the chapter. The committee relocated all of the example diagrams to a new annex because they do not represent all possible system designs. A requirement was added to "General Requirements" to require all systems to be designed for the safe removal of foreign material. There are several ways to isolate or otherwise prevent exposure of personnel to hazardous conditions related to the pulverizer or stand-alone separator. However, incidents were reported indicating that not all systems are equipped with such precautions. Therefore, a requirement was added to remind designers of the importance of this safety feature. An additional general hazard was added to for the influx of ambient air into the negativepressure indirect-fired system. The influx of air into the system could lead to the development of a flammable atmosphere within the pulverized fuel storage or transport system. For both direct-fired and indirect-fired systems, a requirement was added to prohibit the use of water for extinguishing fires in the raw fuel bunker due the potential for high-temperature steam to create an unintentional hazard to personnel in the area. The committee continues to review the use of water-based solutions, such as wetting agents, to determine if such solutions will boil off at the same rate and temperature as water alone. The committee welcomes manufacturers of such products to submit data related to fire performance of their products. The requirements for strength of equipment were extensively revised to be more consistent with NFPA 68 and NFPA 69, resulting in the introduction of new concepts. In the current edition, the strength of equipment refers to "containment of possible explosion pressures." However, the value provided (50 psi) was really a maximum allowable working pressure (MAWP) based on requirements in NFPA 69. NFPA 69 requires that the MAWP be calculated based on the P(max) of the combustible dust involved in the process. The committee identified the P(max) for pulverized coal used in the context of NFPA 85 systems as 10 barg, based on the characteristics of the coal and the typical particle size in the pulverizer and pulverized fuel piping. The committee ran the calculation from NFPA equation 13.1 and determined that a MAWP of 50 psi is acceptable when the operating pressure is 2 psi or less, and an MAWP of 3.4 times the operating pressure is acceptable when the operating pressure is greater than 2 psi, assuming in both cases that the coal P(max) is 10 barg or less. The committee added requirements for calculating the MAWP in accordance with NFPA 68 and NFPA 69 where the coal P(max) is greater than 10 barg. The committee will continue to collect data on this issue to determine if a P(max) of greater than 10 barg is likely or realistic for commonly-available coal or other fuel used in PFS systems under the scope of NFPA 85. The committee welcomes any data that is available. The committee also clarified the use of a vertical column of fuel to resist passage of air or gas from the pulverizer into the raw fuel bunker as three pipe diameters or hydraulic diameters for noncircular pipe. Public Input No. 152-NFPA [Section No ] Public Input No. 161-NFPA [Section No ] Public Input No. 162-NFPA [Section No ] Public Input No. 163-NFPA [Section No (B)] Public Input No. 164-NFPA [Section No [Excluding any Sub-Sections]]

272 Page 500 of 595 First Revision No. 240-NFPA [ Section No ] The air-fuel mixture shall be maintained within safe limits design parameters as established by test under any boiler output condition within the controllable operating range of the subsystem. Submitter Full Name: [ Not Specified ] Organization: [ Not Specified ] Submittal Date: Tue Mar 12 10:06:02 EDT 2013 The term "safe limits" is replaced with "design parameters" because it is unenforceable language. Public Input No. 218-NFPA [Section No ] Public Input No. 220-NFPA [Section No ]

273 Page 501 of 595 First Revision No. 241-NFPA [ Section No [Excluding any Sub-Sections] ] When the rate of furnace input is being changed, the airflow and fuel flow shall be changed simultaneously at the proper rates to maintain a safe the air fuel ratio within design parameters during and after the change. Submitter Full Name: [ Not Specified ] Organization: [ Not Specified ] Submittal Date: Tue Mar 12 10:08:05 EDT 2013 The term "safel" is replaced because it is unenforceable language. Public Input No. 219-NFPA [Section No [Excluding any Sub-Sections]]

274 Page 502 of 595 First Revision No. 45-NFPA [ Section No. A.4.1 ] A.4.1 Safety in any plant is directly influenced by an extensive upfront effort in the engineering, design, and selection of equipment for each individual application. Project inception phase. In the project inception phase, the following should be accomplished to ensure a plant design that meets expected operating modes and reliability needs: (1) Establishment of plant operating parameters. (2) Identification of site-related constraints. (3) Review of steam cycle, including generating a family of heat balance diagrams for the expected operating ranges and modes. (4) Conceptualization of plant layout to provide for personnel safety, operability, and maintenance needs. (5) Definition and verification of requirements of worst-case operating transients, including start-ups. (6) Definition of required test program. (7) Definition of start-up criteria and goals. (8) Identification of the authority having jurisdiction. If multiple authorities having jurisdiction are identified, the scope of each authority having jurisdiction should be determined. (9) Establishment of electrical area classifications by the owner or the owner's designated representative in conjunction with the boiler or HRSG system designer. Equipment planning. The project should consider the use of dynamic simulation, prior operating experience, or both before equipment is selected. Dynamic simulation, where utilized, should include development of the following: (1) Configuration and data initialization (2) Plant behavior knowledge (3) Preliminary control system design and tuning (4) Validation of operating requirements (system performance) (5) Transients and ramps for intended and unintended operation Submitter Full Name: Jenny Depew Organization: NFPA Submittal Date: Mon Jan 14 11:20:44 EST 2013

275 Page 503 of 595 The committee deleted the run-in headings to comply with the NFPA Manual of Style.

276 Page 504 of 595 First Revision No. 148-NFPA [ New Section after A ] A For further information on process hazard analyses (PHA), users can reference the AIChE Center for Chemical Process Safety publication Guidelines for Hazard Evaluation Procedures. The PHA should at least address facility siting, personnel exposures, and manual intervention for resetting after emergency shutdown. Submitter Full Name: [ Not Specified ] Organization: [ Not Specified ] Submittal Date: Fri Feb 01 14:58:29 EST 2013 Annex text is added to support the adoption of a process hazard analysis and identify an additional resource for users.

277 Page 505 of 595 First Revision No. 121-NFPA [ New Section after A ] A The evacuation/purging, charging, and confirmation of fuel gas supply in the piping system upstream of the equipment isolation valve is governed by NFPA 54, National Fuel Gas Code, or NFPA 56, Standard for Fire and Explosion Prevention During Cleaning and Purging of Flammable Gas Piping Systems. NFPA 54 covers fuel gas piping systems up to 860 kpa (125 psig) operating pressure that are not located in electric utility power plants. NFPA 56 covers all other applications. Careful consideration should be given to the potential hazards that might be created in the surrounding area for any fuel gas discharge. Submitter Full Name: [ Not Specified ] Organization: [ Not Specified ] Submittal Date: Wed Jan 30 09:39:55 EST 2013 Notes: Date Submitted By Apr 4, 2013 The annex material is added to further clarify the mandatory requirement and provide guidance on which document is appropriate for a particular application. K. Ritchie A inserted SI measurement for 125 psig, please verify; changed 'may' to 'might', to avoid use of 'may' per MOS. Public Input No. 207-NFPA [New Section after A.4.1.5]

278 Page 506 of 595 First Revision No. 8-NFPA [ New Section after A ] A The area surrounding boilers or HRSGs that meet the requirements of are not classified as a hazardous (classified) location due solely to the presence of their associated burners and fuel feed piping. However, users are cautioned that valves, flanges, fittings, ventilation, or other pieces of equipment can impact the electrical classification of the area around a boiler or HRSG. Therefore, users should be familiar with the guidance in NFPA 497, Recommended Practice for the Classification of Flammable Liquids, Gases, or Vapors and of Hazardous (Classified) Locations for Electrical Installations in Chemical Process Areas, and NFPA 499, Recommended Practice for the Classification of Combustible Dusts and of Hazardous (Classified) Locations for Electrical Installations in Chemical Process Areas. Submitter Full Name: Kimberly Shea Organization: National Fire Protection Assoc Submittal Date: Fri Jan 11 11:08:42 EST 2013 NFPA 497 section states "Open flames and hot surfaces associated with the operation of certain equipment, such as boilers and fired heaters, provide inherent thermal ignition sources. Electrical classification is not appropriate in the immediate vicinity of these facilities. However, it is prudent to avoid installing electrical equipment that could be a primary ignition source for potential leak sources in pumps, valves, and so forth, or in waste product and fuel feed lines." Therefore, NFPA 85 incorporates requirements for safe design and maintenance of equipment in its scope to maintain system integrity and minimize hazards related to fuel systems. However, there are many factors that should be considered in identifying electrically classified areas around such equipment. Users must use caution when identifying electrically classified areas and use appropriate recommended practices and good engineering judgment. Notes: Date Submitted By Apr 4, 2013 K. Ritchie A added full titles for NFPA 497 and 499, per style Public Input No. 102-NFPA [New Section after A.4.1.5]

279 Page 507 of 595 First Revision No. 56-NFPA [ Section No. A ] A The installation of a boiler or HRSG in accordance with the requirements of this code does not in and of itself require a change to the electrical classification of the boiler or HRSG location. Submitter Full Name: Kimberly Shea Organization: National Fire Protection Assoc Submittal Date: Mon Jan 14 15:59:22 EST 2013 The annex note was relocated to the mandatory text.

280 Page 508 of 595 First Revision No. 47-NFPA [ Section No. A ] A As part of the coordination of design, construction, and operation, consideration should be given to the impact of human error and unfavorable function design. Human error. Statistics indicate that human error is a contributing factor in the majority of explosions. It is important to consider whether the error was a result of any of the following: (1) Lack of understanding of, or failure to use, proper operating procedures, safeguards, and equipment (2) Unfavorable operating characteristics of the equipment or its control (3) Lack of functional coordination of the various components of the steamgenerating system and its controls Unfavorable function design. Explosions also can occur as a result of unfavorable functional design. Investigations frequently reveal human error but completely overlook the chain of causes that triggered the operating error. Therefore, the design, installation, and functional objectives of the overall system of components and their controls should be integrated. Consideration should be given to the existing ergonomics that can affect system operation. Submitter Full Name: Jenny Depew Organization: NFPA Submittal Date: Mon Jan 14 11:22:39 EST 2013 The committee added lead-in text and deleted the run-in headings to comply with the NFPA Manual of Style.

281 Page 509 of 595 First Revision No. 144-NFPA [ New Section after A ] A Special consideration should be given to the fire hazards imposed by leakage or rupture of piping at the burner. Particular attention should be given to the integrity of flexible hoses and swivel joints. Submitter Full Name: [ Not Specified ] Organization: [ Not Specified ] Submittal Date: Wed Jan 30 17:47:00 EST 2013 The committee added annex text to provide useful information on this subject. Public Input No. 121-NFPA [New Section after A ]

282 Page 510 of 595 First Revision No. 129-NFPA [ Section No. A ] A The arrangement of air inlets, ductwork, and air preheaters should be designed to avoid unintentional contamination of the air supply by flue gas, water, fuel(s), and other materials. This is not intended to discourage or prohibit flue gas recirculation in properly designed systems. Hazardous contamination can consist of the presence of combustible or explosive material, reduction of the oxygen content of the air supply, or that which interferes with the operation of combustion equipment or instrumentation by such mechanisms as pluggage. While contamination from adjacent processes has always been a consideration in industrial applications, the use of emission control equipment has added new possible sources of contamination to the boiler environment. Submitter Full Name: [ Not Specified ] Organization: [ Not Specified ] Submittal Date: Wed Jan 30 12:08:21 EST 2013 The annex material was modified to incorporate unenforceable language from the body of the code. The annex was relocated to the parent paragraph because it is valuable information for the user.

283 Page 511 of 595 First Revision No. 36-NFPA [ Section No. A ] A (3) The designer is cautioned that, when boilers or HRSGs share a common component between the furnace outlet and the stack, a positive pressure at the tiein point could create a reverse flow into a nonoperating unit when at least one unit is in operation. Submitter Full Name: Kimberly Shea Organization: National Fire Protection Assoc Submittal Date: Fri Jan 11 14:11:28 EST 2013 Annex material moved to go with new (C). Notes: Date Submitted By Apr 8, 2013 K. Ritchie A (3) - changed "C" to "3" (see (3) in Ch. 4)

284 Page 512 of 595 First Revision No. 133-NFPA [ Section No. A ] A Flue gas path auxiliary systems include but are not limited to sulfur burner systems, ammonia injection systems, activated carbon injection systems, soot blowing or soot cleaning systems, electrostatic precipitators, and fired reheater systems. Sulfur burner systems are used primarily to improve the collection efficiency of electrostatic precipitators. Ammonia injection systems can be used to improve the collection efficiency of electrostatic precipitators or as a reagent to provide a reduction in NOx emissions in either SCR or selective noncatalytic reduction (SNCR) systems. Activated carbon injection systems are used primarily to provide a reduction in mercury emissions. Soot blowing or soot cleaning systems are used to improve heat transfer, and include water- and steam-based systems as well as and acoustic based systems, that utilize the acoustic energy of which can be developed by compressed air or pulsed combustion equipment to develop the acoustic energy present a hazard. Submitter Full Name: [ Not Specified ] Organization: [ Not Specified ] Submittal Date: Wed Jan 30 14:13:35 EST 2013 The annex material was revised to reflect movement of the system definitions to the mandatory text. Public Input No. 57-NFPA [Section No. A ] Public Input No. 84-NFPA [Section No. A ] Public Input No. 241-NFPA [Section No. A ]

285 Page 513 of 595 First Revision No. 143-NFPA [ New Section after A.4.11 ] A See A A Not all conditions conducive to a furnace explosion or implosion are detected by the mandatory automatic trip devices, even if the devices are adjusted and maintained in accordance with the manufacturer s instructions and as required by this code. Submitter Full Name: [ Not Specified ] Organization: [ Not Specified ] Submittal Date: Wed Jan 30 17:27:59 EST 2013 The annex material is added to support new requirements in new

286 Page 514 of 595 First Revision No. 145-NFPA [ Section No. A.4.11 ] A.4.11 Utilizing the equivalency provision in Section 1.5, an alternative design to meet the requirements of the code can be accomplished where all the following are provided: (1) Approval of the authority having jurisdiction. (2) A documented hazard analysis that addresses all the requirements of this code. (3) A documented life-cycle system safety analysis that addresses all requirements of this code and incorporates the appropriate application-based safety integrity level (SIL) for safety instrumented systems (SIS). One methodology for achieving a life-cycle system safety analysis is to use a process that includes SIL determination and a SIS design and implementation consistent with the ANSI/ ISA , Application of Safety Instrumented Systems for the Process Industry, or IEC 61511, Functional Safety -- Safety Instrumented Systems for the Process Industry Sector standard series. The designer or designers have the responsibility to ensure that all the hazards identified in this code are adequately addressed in the alternative design. It should be noted that the intent of the independence requirements in through of this code include the following: (1) Separating the burner management system from other systems to reduce the risk of human errors (2) Providing layers of protection and security to reduce risk by having dedicated protection functions in the burner management system (3) Reducing risks through elimination of common mode failures (4) Providing protective features that independently limit process parameters that complement other control systems Submitter Full Name: [ Not Specified ] Organization: [ Not Specified ] Submittal Date: Wed Jan 30 17:56:02 EST 2013 Notes: The reference to IEC is added and the title of ANSI/ISA is corrected.

287 Page 515 of 595 Date Submitted By Apr 4, 2013 K. Ritchie A.4.11(3) - edited IEC title to match how shown on IEC website Public Input No. 192-NFPA [Section No. A.4.11]

288 Page 516 of 595 First Revision No. 15-NFPA [ New Section after A ] A The intent of monitoring the signals for divergence or fault is to provide operators with a means to identify switches or transmitters that are malfunctioning. Users or operators should use this information to identify and take corrective actions, as appropriate, to restore the system to design functionality. Submitter Full Name: Kimberly Shea Organization: National Fire Protection Assoc Submittal Date: Fri Jan 11 11:50:44 EST 2013 Existing section requires that multiple switches or transmitters be monitored for disagreement with each other but does not explicitly state what is to be done if a disagreement is detected. The proposed annex text clarifies the intent of the requirement and recommends that action be taken.

289 Page 517 of 595 First Revision No. 76-NFPA [ Section No. A (10) ] A (10) Watchdog timers as defined in are one of the possible means to implement monitoring of the logic system for failure. A watchdog timer is a timer external to a microprocessor-based control that is used to compare the microprocessor cycle timing against itself and that fails safely if the microprocessor timing stops or exceeds the watchdog time interval. Submitter Full Name: [ Not Specified ] Organization: [ Not Specified ] Submittal Date: Tue Jan 29 14:03:00 EST 2013 The annex material is modified to incorporate the definition for watchdog timer as published in the 2011 edition. The term watchdog timer is no longer used in the mandatory text, and therefore the definition is removed from chapter 3 in a separate action.

290 Page 518 of 595 First Revision No. 53-NFPA [ Section No. A.4.13 ] A.4.13 Users of this code are encouraged to use judgment in the application of the following guidelines for all process and safety functions contained in a distributed control system. (1) For data transmission, the following should be considered: (a) (b) Every input should be sampled at intervals of no more than 1 second. Every output should be updated at intervals of no more than 1 second. For protective actions, the system should be able to convert a changed input sensor value to a completed output control action in 250 milliseconds or less than 25 milliseconds. (c) Changes in displayed data or status should be displayed within 5 seconds. (d) Data acquisition and transmission systems should be protected from noise pickup and electrical interference. (e) In redundant systems, the data links should be protected from common mode failures. Where practicable, redundant data links should be routed on separate paths to protect against physical damage that disables both data links. (2) For hardware, the following should be considered: (a) (b) (c) (d) (e) (f) (g) The hardware selected should have adequate processor capacity to perform all the functions required for start-up sequencing, normal operation alarming, monitoring, and shutdown of the controlled equipment. Capacity also should be available for data storage and sorting; this capacity can be permitted to be located in a separate processor. Selection should take into consideration the requirements for reliability, maintainability, and electrical classification. The hardware should provide for automatic tracking between automatic and manual functions to allow for immediate seamless transfer. The hardware should be capable of stable dynamic control. The hardware should be capable of thorough self-diagnosis. Consideration should be given to all levels and types of electrical interference that can be tolerated by the hardware without compromising its reliability or effectiveness. Fail-safe operation should be obtained through a thorough and complete analysis of each control loop and by providing for a failure of that loop (i.e., valve/actuator) to cause a fail-safe position. (3) For software, the following should be considered:

291 Page 519 of 595 (a) (b) (c) (d) (e) (f) The software package should be designed to include all logic to provide a safe and reliable control system. When the software calls for the operation of a field safety device, a feedback signal should be provided to prove that the requested operation has taken place, and an alarm should be actuated if the action is not confirmed in a specified amount of time. The software package should be checked to ensure that no unintended codes or commands are present (e.g., viruses or test breaks). The software package should be tested and practiced before being loaded into the plant site computers or processors. The software system should be protected from inadvertent actions by operators and should be tamperproof. Written procedures should specify the functions that can and cannot be accessed by the operator and those functions that require additional authorization for access. The software should be permitted to provide for authorized on-line changes of the timers and set points, provided the safety of the operating equipment is not compromised. The software should implement and enhance the self-diagnostic hardware. Submitter Full Name: Kimberly Shea Organization: National Fire Protection Assoc Submittal Date: Mon Jan 14 11:32:07 EST 2013 Section A includes text that is essentially the same as A.4.13 with the difference being that section requires less than 250 milliseconds. This difference has existed since the 2001 edition and prior to that NFPA appears to have been the only document in the 8500 series that had this requirement at all. It is believed that the 25 millisecond requirement is extreme and probably a typographical error in the 2001 edition that has cascaded through each successive edition. Also, it makes sense to change the requirement to or less since a 1 millisecond difference (249 versus 250) is insignificant and would provide for the use of an even fraction of 1 second. Public Input No. 85-NFPA [Section No. A.4.13]

292 Page 520 of 595 First Revision No. 137-NFPA [ New Section after A ] A.4.15 In addition to the requirements of this code, the designer should apply good engineering practice of an alarm management system and human-machine interface based on currently available standards and publications, such as ANSI/ISA 18.2, Management of Alarm Systems for the Process Industries ISA TR18.2.4, Enhanced and Advanced Alarm Methods ; ISA TR18.2.5, Alarm System Monitoring, Assessment, and Auditing ; and EEMUA 191, Alarm Systems -- A Guide to Design, Management, and Procurement. Submitter Full Name: [ Not Specified ] Organization: [ Not Specified ] Submittal Date: Wed Jan 30 16:17:51 EST 2013 The Operating Information requirements specified in clause 4.15 is a very limited set of requirements for a good alarm management system and human machine interface. NFPA 85 does not completely address the requirements of an alarm management system or human-machine interface design and therefore the annex encourages the designer to apply available practices and identifies additional resources to do so. Public Input No. 51-NFPA [Section No. 4.15]

293 Page 521 of 595 First Revision No. 237-NFPA [ Section No. A ] A Analyzers could contain heated elements that exceed the autoignition temperature of many fuels. Zirconium oxide analyzers, commonly used for oxygen analysis, contain an element heated to 704 C 1300 F (1300 F 704 C ). This high temperature element presents a potential ignition source to unburned fuel that could be present during pre-purge or at startup. Some analyzers are designed to protect the sampled space from the ignition source by providing flashback protection (such as flame arresters in the sample gas path). Analyzers with that protection or that are not heated to autoignition temperature do not present an ignition hazard. It should be noted, however, that flame arrestors might only work below a certain temperature which is usually not quantified, might not quench a flame as well once it becomes corroded, and might induce a speed of response delay that could be detrimental to the control or protection strategy. Consideration should be given to powering down analyzers during boiler or fuel trip situations if they can exceed the autoignition temperature of the fuel being fired. Submitter Full Name: [ Not Specified ] Organization: [ Not Specified ] Submittal Date: Thu Mar 07 14:03:11 EST 2013 Notes: Date Submitted By Apr 4, 2013 Discussions with a major supplier of zirconium oxide based oxygen analyzers revealed the stated limitations of flame arrestors and those limitations need to be understood by users of the Code. K. Ritchie A transposed temperature measurements to conform to 'SI(US)' style; changed 'may' to 'might' in three instances, to avoid 'may' per MOS Public Input No. 65-NFPA [Section No. A ]

294 Page 522 of 595 First Revision No. 229-NFPA [ New Section after A ] A (3) SIL 2 capable was purposely specified as the minimum safety level based on the existing safety levels presently required in this code, which can be considered SIL 2, SIL 1, and/or SIL 0. The notified body or third-party certification is critical in the SIL 2 capable requirement because self-certification is permitted in the safety rated PLC marketplace, and with self-certification there is no assurance that critical safety functions, such as the secure separation of the safety and process logic, are provided. Use of a logic system that has been self-certified is not permitted. Isolation between the burner management system and the other logic can be accomplished by using separate processors or by selecting a single processor that ensures isolation through the use of an isolated programming area protected by locks or passwords. Submitter Full Name: [ Not Specified ] Organization: [ Not Specified ] Submittal Date: Thu Mar 07 11:17:11 EST 2013 The annex text is added to support new subparagraph added in FR 228. Public Input No. 213-NFPA [New Section after A (1)]

295 Page 523 of 595 First Revision No. 158-NFPA [ Section No. A ] A Unattended operation of larger units is not recommended. Submitter Full Name: [ Not Specified ] Organization: [ Not Specified ] Submittal Date: Tue Feb 26 12:50:45 EST 2013 The committee did not relocate the annex text to the new because the term "larger units" does not provide instructional guidance for all equipment covered by NFPA 85. The mandatory text of 6.

296 Page 524 of 595 First Revision No. 159-NFPA [ Section No. A ] A The mandatory automatic trips specified in represent that portion of automatic trips for which sufficient experience has been accumulated to demonstrate a high probability of successful applications for all units. The use of additional automatic trips, while not mandatory, is recommended. Submitter Full Name: [ Not Specified ] Organization: [ Not Specified ] Submittal Date: Tue Feb 26 13:36:52 EST 2013 Notes: Date Submitted By Feb 26, 2013 [ Not Specified ] Subsection was deleted in its entirety. Therefore, the committee relocated the annex material from A to a new A so it would not be lost. Add asterisk to Public Input No. 45-NFPA [Section No ]

297 Page 525 of 595 First Revision No. 161-NFPA [ Section No. A ] A In block 6 of Table (a), high furnace pressure could be caused by tube rupture, damper failure, or explosion. In block 8 of Table (a), the partial loss of flame described is potentially more hazardous at lower load levels. The decision regarding specific requirements or implementation of this trip should be a design decision based on furnace configuration, total number of burners, number of burners affected as a percentage of burners in service, arrangement of burners affected, interlock system, and load level. This trip is interlocked through flame supervisory equipment. In block 9 of Table (a), the tables referenced describe the allowable differences in operating procedures based on the classification of igniter being used. The following descriptions of conditions are typical for both Table (b) and Table (c). (1) Condition 1: An event in which, after a successful boiler purge, an attempt(s) to place the first igniter in service fails (2) Condition 2: An event in which an igniter(s) has been proven in service and subsequently all igniters are shut down without the attempt ever having been made to place a burner or pulverizer in service (3) Condition 3: An event in which gas and/or oil fuel burners were started or attempted to be started and all burner valves were subsequently closed while igniters remain proven in service (4) Condition 4: An event in which a pulverizer system(s) was started up or attempted to be started up and subsequently all pulverizer systems were shut down while igniters remain proven in service (5) Condition 5: An event in which any fuel has been placed in service and all fuel subsequently shut off In the event that any main fuel is shut down while any other main fuel remains proven in service, the all-fuel-off master fuel trip requirements do not apply. In block 10a of Table (a), low drum water level has been included as a master fuel trip. Although low drum water level is not a combustion-related hazard, NFPA 85 this code is the primary resource for identifying BMS requirements, and not including a low drum level trip in Figure has created confusion with users of this code. A master fuel trip based on low drum water level for drum-type boilers is commonly recognized good engineering practice. In block 10b of Table (a), low feedwater flow is also not a combustion related hazard. The low feedwater flow threshold could be a fixed value or a function of the boiler load based on the boiler manufacturer s recommendations. Submitter Full Name: [ Not Specified ] Organization: [ Not Specified ] Submittal Date: Tue Feb 26 15:08:15 EST 2013

298 Page 526 of 595 The committee added new annex text to support modifications to Table (a) made in FR 160. Feedwater flow below the design minimum is a hazard. However, there are instances when flow is above the design minimum, but is too low to support the furnace firing rate. The manufacturer should identify these conditions and specify the appropriate trip points.

299 Page 527 of 595 First Revision No. 165-NFPA [ New Section after A (C) ] A (C)(4) The tripped unit should be isolated if required to prevent backflow of flue gases from operating units. Submitter Full Name: [ Not Specified ] Organization: [ Not Specified ] Submittal Date: Tue Feb 26 16:26:33 EST 2013 Annex text was added to clarify the intent of the new requirement in (C)(3). Notes: Date Submitted By Apr 8, 2013 K. Ritchie A (C)(4) - replaced "(3)" with "(4)", to correspond with asterisk in code

300 Page 528 of 595 First Revision No. 167-NFPA [ New Section after A (C) ] A (D)(1) When shutting down a unit, it is preferable to maintain an open-flow path through the boiler enclosure. Submitter Full Name: [ Not Specified ] Organization: [ Not Specified ] Submittal Date: Tue Feb 26 17:00:38 EST 2013 The committee relocated unenforceable language from the mandatory text to the annex. Public Input No. 108-NFPA [New Section after A (C)]

301 Page 529 of 595 First Revision No. 168-NFPA [ New Section after A (C) ] A (D)(2) In some conditions, owners/operators could prefer to close all boiler enclosure dampers to retain heat within the boiler. Additional provisions, such as manual fuel isolation, should be considered when closing all dampers to prevent accumulation of combustibles in the boiler enclosure. For coal-fired or oil-fired units, maintaining airflow through the unit to prevent accumulation of combustible gases is prudent. Submitter Full Name: [ Not Specified ] Organization: [ Not Specified ] Submittal Date: Tue Feb 26 17:05:59 EST 2013 Additional annex material to caution the owner/operator that closing the boiler dampers may create an additional hazard. Additional actions should be considered when the boiler enclosure is closed off. Public Input No. 109-NFPA [New Section after A (C)]

302 Page 530 of 595 First Revision No. 169-NFPA [ Section No. A (2) ] A (2) Analyzers could contain heated elements that exceed the autoignition temperature of some fuels. Zirconium oxide analyzers, commonly used for oxygen analysis, contain an element heated to 704 C 1300 F (1300 F 704 C ). This high temperature element presents a potential ignition source to unburned fuel that could be present at startup. Some analyzers are designed to protect the sampled space from the ignition source by providing flashback protection (such as flame arresters in sample gas path). Analyzers with that protection or that are not heated to autoignition temperature do not present an ignition hazard. It should be noted, however, that flame arrestors might only work below a certain temperature which is usually not quantified, might not quench a flame as well once it becomes corroded, and might induce a speed of response delay that could be detrimental to the control or protection strategy. Consideration should be given to powering down analyzers during boiler or fuel trip situations if they can exceed the autoignition temperature of the fuel being fired. Submitter Full Name: [ Not Specified ] Organization: [ Not Specified ] Submittal Date: Tue Feb 26 17:25:43 EST 2013 Notes: Date Submitted By Apr 5, 2013 Discussions with a major supplier of zirconium oxide based oxygen analyzers revealed the stated limitations of flame arrestors and those limitations need to be understood by users of the Code. K. Ritchie A (2) - transposed temperature measurements to conform to 'SI(US)' style; changed 'may' to 'might' in three instances, to avoid 'may' per MOS Public Input No. 66-NFPA [Section No. A (2)]

303 Page 531 of 595 First Revision No. 171-NFPA [ New Section after A ] A If fan pairing is used, the fan pairing is usually such that each pairing consists of one or more ID fans paired to one FD fan. If the FD fan is paired with multiple ID fans, it is not necessary to trip the FD fan if at least one of the ID fans in the pairing remains running. Submitter Full Name: [ Not Specified ] Organization: [ Not Specified ] Submittal Date: Tue Feb 26 17:36:33 EST 2013 The committee added annex text to support revisions to

304 Page 532 of 595 First Revision No. 175-NFPA [ New Section after A ] A (B) FD fans are typcially not used to control furnace pressure. However, loss of ID fans requires a master fuel trip, and the subsequent flame collapse, along with the loss of FD fans, can create a severe negative furnace pressure excursion. Delayed tripping of the FD fan(s) could result in reducing the severity of negative furnace pressure excursion, thus aiding in maintaining furnace pressure within limits. The transient analysis also needs to consider the potential for positive pressure rebound during this scenario. Submitter Full Name: [ Not Specified ] Organization: [ Not Specified ] Submittal Date: Wed Feb 27 10:48:16 EST 2013 Provide clarification to revised paragraph (B). Notes: Date Submitted By Apr 5, 2013 K. Ritchie A (B) - deleted 'MFT' and replaced with 'master fuel trip' to match style of rest of code Public Input No. 37-NFPA [New Section after A ]

305 Page 533 of 595 First Revision No. 220-NFPA [ Section No. A ] A A short time delay might be necessary to prevent tripping on rapid transients that do not present a hazard. Submitter Full Name: [ Not Specified ] Organization: [ Not Specified ] Submittal Date: Tue Mar 05 14:36:34 EST 2013 The mandatory text and its associated annex text are deleted.

306 Page 534 of 595 First Revision No. 183-NFPA [ Section No. A ] A The ID fan head capability increases due to significant draft losses beyond the air heater or for other reasons, such as excessive ID fan test block margins. Where the ID fan test block capability is more negative than -8.7 kpa (-35 in. of water), consideration should be given to an increased negative design pressure. Examples: If the test block capability of the ID fan at ambient temperature is -3.7 kpa (-15 in. of water), then the minimum negative design pressure is -3.7 kpa (-15 in. of water). If the test block capability of the ID fan at ambient temperature is -9.9 kpa of water (-40 in. of water), then the minimum negative design pressure is -8.7 kpa (-35 in. of water). Negative pressure transients associated with a master fuel trip should be analyzed. Methods, such as designing the appropriate closing time of the individual burner safety shutoff valves and the main fuel safety shutoff valve, can be utilized to help minimize excessive negative furnace pressure transients. Generally, closure times of 3 to 5 seconds can be expected to help mitigate negative pressure transients. Submitter Full Name: [ Not Specified ] Organization: [ Not Specified ] Submittal Date: Wed Feb 27 14:23:35 EST 2013 Notes: Date Submitted By Apr 5, 2013 The revision adds clarification that slowing the valve closure times can have a positive impact on negative furnace pressure. K. Ritchie A deleted 'MFT' and replaced with 'master fuel trip' to match style of rest of code Public Input No. 38-NFPA [Section No. A ]

307 Page 535 of 595 First Revision No. 194-NFPA [ Section No. A ] A Special recognition should be given to the fire hazards imposed by leakage or rupture of piping at the burner. Submitter Full Name: [ Not Specified ] Organization: [ Not Specified ] Submittal Date: Wed Feb 27 15:55:07 EST 2013 The text was added to A in FR 144. Therefore, it is deleted because it is redundant to chapter 4. Public Input No. 123-NFPA [Section No. A ]

308 Page 536 of 595 First Revision No. 26-NFPA [ New Section after A ] A Maintaining airflow through the unit to prevent accumulation of combustible gases is a prudent procedural step due to the potential of fuel leak-by. Submitter Full Name: Kimberly Shea Organization: National Fire Protection Assoc Submittal Date: Fri Jan 11 12:18:04 EST 2013 Unenforceable language is moved from the body of the code to the annex.

309 Page 537 of 595 First Revision No. 193-NFPA [ Section No. A ] A Special recognition should be given to the fire hazards imposed by leakage or rupture of piping at the burner. Particular attention should be given to the integrity of flexible hoses and swivel joints. Submitter Full Name: [ Not Specified ] Organization: [ Not Specified ] Submittal Date: Wed Feb 27 15:52:45 EST 2013 The annex material was added to new A in FR 144. Therefore, it is deleted from this section because it is redundant to chapter 4. Public Input No. 126-NFPA [Section No. A ]

310 Page 538 of 595 First Revision No. 29-NFPA [ New Section after A ] A Maintaining airflow through the unit to prevent accumulation of combustible gases is a prudent procedural step due to the potential of fuel leak-by. Submitter Full Name: Kimberly Shea Organization: National Fire Protection Assoc Submittal Date: Fri Jan 11 12:27:19 EST 2013 The committee moved unenforceable language from to the annex.

311 Page 539 of 595 First Revision No. 49-NFPA [ Section No. A ] A When the boiler is operating with pulverized coal for an extended time at reduced loads, incomplete combustion can cause large quantities of unburned combustible dust to settle in hoppers and on horizontal surfaces. If this dust is disturbed by a rapid increase in airflow or by sootblowing, an explosive mixture can result. This condition has been the cause of several explosions. Submitter Full Name: Jenny Depew Organization: NFPA Submittal Date: Mon Jan 14 11:26:34 EST 2013 The committee deleted the annex material because it is redundant to the CAUTION statement in the mandatory text.

312 Page 540 of 595 First Revision No. 195-NFPA [ Section No. A ] A Special attention should be given to the fire hazards imposed by leakage or rupture of piping near the burner. Submitter Full Name: [ Not Specified ] Organization: [ Not Specified ] Submittal Date: Wed Feb 27 15:56:26 EST 2013 The text is added to A in FR 144. Therefore, it is deleted because it is redundant to chapter 4. Public Input No. 127-NFPA [Section No. A ]

313 Page 541 of 595 (B)(19) ] First Revision No. 34-NFPA [ New Section after A A Maintaining airflow through the unit to prevent accumulation of combustible gases is a prudent procedural step due to the potential of fuel leak-by. Submitter Full Name: Kimberly Shea Organization: National Fire Protection Assoc Submittal Date: Fri Jan 11 13:52:46 EST 2013 Unenforceable language has been moved to the annex.

314 Page 542 of 595 First Revision No. 152-NFPA [ New Section after A (1) ] A (6) Bed solidification can occur as a result of agglomeration. Alkali compounds can attach to bed material particles. These alkali compounds can have low melting points and can cause the bed particles to stick to each other to form agglomerates. Submitter Full Name: [ Not Specified ] Organization: [ Not Specified ] Submittal Date: Wed Feb 20 14:06:37 EST 2013 In discussions with the BCS-FUN TC the definition for agglomeration (3.3.2) is being deleted from chapter 3, Definitions. Defining agglomeration for this specific case precludes the use of the term in other cases within the code where agglomeration is a concern. This public comment offers annex material to (6) to capture and explain how agglomeration occurs in this particular case. Public Input No. 11-NFPA [New Section after A (1)]

315 Page 543 of 595 First Revision No. 153-NFPA [ Section No. A (10) ] A (10) Analyzers could contain heated elements that exceed the autoignition temperature of some fuels. Zirconium oxide analyzers, commonly used for oxygen analysis, contain an element heated to 704 C (1300 F). This high temperature element presents a potential ignition source to unburned fuel that could be present at start - up. Some analyzers are designed to protect the sampled space from the ignition source by providing flashback protection (such as flame arresters in the sample gas path). Analyzers that have that protection or that are not heated to autoignition temperature do not present an ignition hazard. It should be noted, however, that flame arrestors might only work below a certain temperature which is usually not quantified, might not quench a flame as well once it becomes corroded, and might induce a speed of response delay that could be detrimental to the control or protection strategy. Consideration should be given to powering down analyzers during boiler or fuel trip situations if they can exceed the autoignition temperature of the fuel being fired. Submitter Full Name: [ Not Specified ] Organization: [ Not Specified ] Submittal Date: Wed Feb 20 14:21:43 EST 2013 Notes: Date Submitted By Apr 5, 2013 Discussions with a major supplier of zirconium oxide based oxygen analyzers revealed the stated limitations of flame arrestors and those limitations need to be understood by users of the Code. This same change is being proposed against identical annex material in A , A (2) and A (10). K. Ritchie A (10) - replaced 'may' with 'might' in three instances, to avoid 'may' per MOS Public Input No. 67-NFPA [Section No. A (10)]

316 Page 544 of 595 First Revision No. 216-NFPA [ Section No. A ] A Usually this can be accomplished by providing full relieving capacity vented to a safe location in accordance with Submitter Full Name: [ Not Specified ] Organization: [ Not Specified ] Submittal Date: Thu Feb 28 16:01:43 EST 2013 The revision directs users to the vent requirements in Public Input No. 63-NFPA [Section No. A ] Public Input No. 215-NFPA [Section No. A ]

317 Page 545 of 595 First Revision No. 16-NFPA [ New Section after A ] A In general, three safety shutoff valves on the main header is the preferred practice, but in some situations, this might not be practical. Submitter Full Name: Jenny Depew Organization: NFPA Submittal Date: Fri Jan 11 11:52:24 EST 2013 Notes: Date Apr 5, 2013 This Annex material is being added for consistency with FR 14, new Section * Submitted By K. Ritchie A changed 'may' to 'might'

318 Page 546 of 595 First Revision No. 207-NFPA [ New Section after A ] A Vents, drains, and telltales should discharge in such a way to protect personnel from injury and to prevent the creation of a fire or explosion hazard. Submitter Full Name: [ Not Specified ] Organization: [ Not Specified ] Submittal Date: Thu Feb 28 11:35:39 EST 2013 The requirement was revised to apply to only relief valve discharge piping in FR 206. The annex material is added to provide guidance to users for vents, drains, and telltales.

319 Page 547 of 595 First Revision No. 217-NFPA [ Section No. A ] A For guidance in determining area classification, see NFPA 497, Recommended Practice for the Classification of Flammable Liquids, Gases, or Vapors and of Hazardous (Classified) Locations for Electrical Installations in Chemical Process Areas ; NFPA 499, Recommended Practice for the Classification of Combustible Dusts and of Hazardous (Classified) Locations for Electrical Installations in Chemical Process Areas ; NFPA 70, National Electrical Code, Article 500; and either API RP 500, Recommended Practice for Classification of Locations for Electrical Installations at Petroleum Facilities Classified as Class I, Division 1 and Division 2, or API RP 505, Recommended Practice for Classification of Locations for Electrical Installations at Petroleum Facilities Classified as Class I, Zone 0, Zone 1, and Zone 2. Submitter Full Name: [ Not Specified ] Organization: [ Not Specified ] Submittal Date: Thu Feb 28 16:05:27 EST 2013 Notes: Date Submitted By Feb 28, 2013 Change the Electrical Area Classification appendix reference from A to A Paragraph is the only requirement for defining Electrical area classification in chapter 8. The appendix provides references for determining that classification which seems better suited to than Paragraph addresses electrical design requirements for hazardous locations. [ Not Specified ] The result of the action is to relocate the annex item to A Public Input No. 199-NFPA [Section No. A.8.6.4]

320 Page 548 of 595 First Revision No. 25-NFPA [ New Section after A (2) ] A It is not good practice to have air flowing in the reverse direction into the combustion turbine. This reverse flow can come from the augmented or tempering air system. The plant control system could have an interlock to ensure augmented or tempering fans are not started until flow is established through the combustion turbine. Designers and operators should consult the equipment manufacturer's instructions for further information. Submitter Full Name: Jenny Depew Organization: NFPA Submittal Date: Fri Jan 11 12:16:34 EST 2013 Notes: Date Apr 5, 2013 This Annex material is being added for consistency with FR 23, Section * Submitted By K. Ritchie A deleted 'and' and started new sentence with 'This' for clarity

321 Page 549 of 595 First Revision No. 38-NFPA [ Section No. A ] A (A) See Figure A (A). Figure A (A) Gaseous Fuels Triple Block and Double Vent Valve Arrangement. The intent is to ensure that the integrity of the combustion turbine fuel systems and safety controls are maintained. This is particularly important for any retrofit installed to meet the combustion turbine purge credit requirements. This should be accomplished by reviewing existing operating instructions and consulting the original equipment manufacturer of the combustion turbine and ancillary equipment before finalizing a design. On units with a duct burner system, similar considerations should be applied. Submitter Full Name: Jenny Depew Organization: NFPA Submittal Date: Fri Jan 11 15:13:32 EST 2013

322 Page 550 of 595 Annex material added to be consistent with FR 30, Section * The committee restructured the paragraphs to be consistent with the NFPA Manual of Style. The introductory paragraph referred to systems being installed, but the subsequent subparagraphs described operational sequences. The committee separated the requirements from the sequences and renumbered accordingly. The committee added the requirement for a normal duct burner shutdown to make it clear that all systems must be in a "normal" condition in order for the combustion turbine purge credit to be established. The committee added the requirement for meeting the requirements of OEM of the combustion turbine to ensure that the integrity of the combustion turbine fuel systems and safety controls are maintained. This is particularly important for any retrofit installed to meet the combustion turbine purge credit requirements. Notes: Date Submitted By Apr 5, 2013 K. Ritchie A changed 'OEM' to 'original equipment manufacturer'

323 Page 551 of 595 First Revision No. 51-NFPA [ Section No. A (1) ] A (A)(2) The philosophy for combustion turbine normal shutdown includes sufficient postpurge airflow to satisfy the requirements of the combustion turbine purge. purge credit is that a combustion turbine normal shutdown does not result in a hazardous atmosphere being introduced. Therefore, a combustion turbine purge should not be required for subsequent startup provided that a combustion turbine purge credit is maintained. Submitter Full Name: Jenny Depew Organization: NFPA Submittal Date: Mon Jan 14 11:29:01 EST 2013 Notes: Date Submitted By Apr 8, 2013 The existing language was being interpreted to mean that a complete combustion turbine purge was required regardless of combustion turbine purge credit status, which was not the committee's intent. The committee modified the note to specify the intent that combustion turbine purge credit overrules the requirement for combustion turbine purge as long as the purge credit conditions are maintained. K. Ritchie A (1) - there is no corresponding (1) in code. Please advise.

324 Page 552 of 595 First Revision No. 52-NFPA [ Section No. A (1) ] A (B)(2) The philosophy for combustion turbine normal shutdown includes sufficient postpurge airflow to satisfy the requirements of the combustion turbine purge. purge credit is that a combustion turbine normal shutdown does not result in a hazardous atmosphere being introduced. Therefore, a combustion turbine purge should not be required for subsequent startup provided that a combustion turbine purge credit is maintained. Submitter Full Name: Jenny Depew Organization: NFPA Submittal Date: Mon Jan 14 11:31:01 EST 2013 Notes: Date Submitted By Apr 8, 2013 The existing language was being interpreted to mean that a complete combustion turbine purge was required regardless of combustion turbine purge credit status, which was not the committee's intent. The committee modified the note to specify the intent that combustion turbine purge credit overrules the requirement for combustion turbine purge as long as the purge credit conditions are maintained. K. Ritchie A (1) There is no corresponding (1), please advise

325 Page 553 of 595 First Revision No. 214-NFPA [ New Section after A ] A (C) See Figure A (C). The intent of this section is to assure the liquid fuel level in the piping between the fuel supply and the combustor/duct burner nozzles never rises to a height that would allow the fuel to enter the combustion turbine or HRSG. Figure A (C) Liquid Fuels with Liquid Level Sensing. A (C)(3) The philosophy for combustion turbine purge credit is that a combustion turbine normal shutdown does not result in a hazardous atmosphere being introduced. Therefore, a combustion turbine purge should not be required for subsequent startup provided that a combustion turbine purge credit is maintained. A (C)(6) The liquid level monitoring required by this paragraph may be accomplished by means of a level switch, level transmitter, pressure sensor, or any other device that provides a positive indication of liquid level within the piping between the block valves and the fuel nozzles. Supplemental Information File Name Description Figure_A_8_8_4_7_C.pdf New figure A (C). Submitter Full Name: [ Not Specified ] Organization: [ Not Specified ] Submittal Date: Thu Feb 28 15:37:25 EST 2013 Notes: The committee added annex material to support the new liquid level monitoring alternative for establishing purge credit.

326 Vent Fuel t9(} -r~~~-'~ Supply VI V2 To combustion f--t)l(}-~ turbine or V3 duct burner Drain Drain Figure A.8.S System 4 Liquid Fuels with Liquid Level Sensing

327 Page 555 of 595 First Revision No. 39-NFPA [ New Section after A (1) ] A See A Submitter Full Name: Jenny Depew Organization: NFPA Submittal Date: Fri Jan 11 15:19:37 EST 2013 Annex added to be consistent with FR 37 Section *

328 Page 556 of 595 First Revision No. 54-NFPA [ Section No. A (1) ] A (A)(2) The philosophy for combustion turbine normal shutdown includes sufficient postpurge airflow to satisfy the requirements of the combustion turbine purge. purge credit is that a combustion turbine normal shutdown does not result in a hazardous atmosphere being introduced. Therefore, a combustion turbine purge should not be required for subsequent startup provided that a combustion turbine purge credit is maintained. Submitter Full Name: Jenny Depew Organization: NFPA Submittal Date: Mon Jan 14 11:32:38 EST 2013 Notes: Date Submitted By Apr 8, 2013 The existing language was being interpreted to mean that a complete combustion turbine purge was required regardless of combustion turbine purge credit status, which was not the committee's intent. The committee modified the note to specify the intent that combustion turbine purge credit overrules the requirement for combustion turbine purge as long as the purge credit conditions are maintained. K. Ritchie A (1) - there is no corresponding (1). Please advise.

329 Page 557 of 595 First Revision No. 43-NFPA [ New Section after A ] A Where individual burner safety shutoff valves are installed, the pressure should be relieved between the most downstream main safety shutoff valve and the individual burner safety shutoff valves. Submitter Full Name: Kimberly Shea Organization: National Fire Protection Assoc Submittal Date: Mon Jan 14 11:18:22 EST 2013 The committee recognizes that there is no specific requirement to open the vent or drain valves on a normal duct burner shutdown. Pressure should be relieved in the pipe section immediately upstream of the safety shutoff valve (s) closest to the duct burner during a shutdown to prevent the possibility of leakage into the HRSG.

330 Page 558 of 595 First Revision No. 55-NFPA [ Section No. A ] A Figure A (a) through Figure A (j) represent typical fuel supply systems for duct burners. Figure A (a) Typical Duct Burner Gaseous Fuel Ignition System of a Single Element or Multiple Elements Fired Simultaneously (Class 3 Igniter Monitoring Requirements Shown). Figure A (b) Typical Duct Burner Liquid Fuel Ignition System of a Single Burner or Multiple Burners Fired Simultaneously (Class 3 Igniter Monitoring Requirements Shown). Figure A (c) Typical Main Gaseous Fuel Duct Burner System of a Single Element or Multiple Elements Fired Simultaneously. Figure A (d) Typical Steam or Air Atomizing Single Main Liquid Fuel Duct Burner System.

331 Page 559 of 595 Figure A (e) Typical Duct Burner Gaseous Fuel Igniter System. Figure A (f) Typical Main Gaseous Fuel Duct Burner System. Figure A (g) Typical Duct Burner Mechanical Atomizing Light Liquid Fuel Igniter System. Figure A (h) Typical Duct Burner Steam or Air Atomizing Light Liquid Fuel Igniter System.

332 Page 560 of 595 Figure A (i) Typical Mechanical Atomizing Main Liquid Fuel Duct Burner System. Figure A (j) Typical Steam or Air Atomizing Main Liquid Fuel Duct Burner System. Submitter Full Name: Jenny Depew Organization: NFPA Submittal Date: Mon Jan 14 11:33:58 EST 2013 Notes: The caution statement/cross reference has been deleted in Figure A (d). It has been incorrect for two editions and does not appear to be used; therefore, there is no reason to keep it.

333 Page 561 of 595 Date Apr 8, 2013 Submitted By K. Ritchie Figure A (d) - deleted text "DELETE CAUTION STATEMENT ON THE LEGEND. DELETE ASTERISK BETWEEN THE TWO A VALVES IN THE UPPER RIGHT OF THE DIAGRAM", and processed art correction via art coordinator

334 Page 562 of 595 First Revision No. 50-NFPA [ New Section after A ] A Where an isolation damper is closed to isolate the tempering air system from the combustion turbine, it is not critical to purge the tempering air system concurrently with the combustion turbine. Manufacturer's operating instructions should be followed. A It is not good practice to have air flowing in the reverse direction into the combustion turbine. This reverse flow can come from the tempering air system. The plant control system could have an interlock to ensure tempering fans are not started until flow is established through the combustion turbine. Designers and operators should consult the equipment manufacturer's instructions for further information. Submitter Full Name: Kimberly Shea Organization: National Fire Protection Assoc Submittal Date: Mon Jan 14 11:28:38 EST 2013 Where an isolation damper is closed to isolate the tempering air system from the combustion turbine, it is not critical to purge the tempering air system concurrently with the combustion turbine. Manufacturer's operating instructions should be followed. A It is not good practice to have air flowing in the reverse direction into the combustion turbine and this reverse flow can come from the tempering air system. The plant control system could have an interlock to ensure tempering fans are not started until flow is established through the combustion turbine. Designers and operators should consult the equipment manufacturer's instructions for further information. Notes: Date Submitted By Apr 5, 2013 K. Ritchie A deleted "and" and started new sentence with "This"

335 Page 563 of 595 First Revision No. 227-NFPA [ Sections A.9.1.1, A.9.3.1, A.9.3.2, A , A ] A Use of fuel blends with individual fuels having less than 8 percent volatility on a moisture-free basis should be discussed fully with the manufacturer. A Pulverizing and fuel system component functions include the following: (1) Drying and conveying of fuel. Pulverizer air is used to continuously convey the pulverized fuel from the pulverizer. Normally, heated pulverizer air evaporates some of the moisture from the raw fuel while it is being pulverized, and it elevates the air-fuel mixture to the desired temperature. The temperature and quantity of pulverizer air that is used are controlled to obtain the desired degree of dryness and pulverizer outlet temperature, depending on the type of fuel being burned. (2) Classifying the pulverized fuel. An essential characteristic of the pulverized product is its fineness. It is desirable that the pulverized fuel system minimize variation in fineness, because pulverizer parts exhibit wear and fuel properties change over the anticipated range. For this purpose, most pulverizers are equipped with adjustable classifiers or achieve some adjustment of fineness by varying air flow or other means. (3) Transporting and distributing the pulverized fuel. The pulverized fuel should be transported directly to one or more burners, to one or more air-fuel separation devices, or to one or more bins or lock hoppers for intermediate storage. (4) Refuse removal. It is desirable that foreign, hard-to-grind material be removed from the fuel before it is fed to the pulverizers; however, it is advisable that the pulverizers either reject or tolerate reasonable amounts of such materials so that damage or interruption of service does not result. The refuse removal system should be designed to protect personnel from exposure to hot gases that are present in the pulverizer. This could be accomplished through the use of manual gates, isolation valves, operating procedures, or a combination thereof. A The design, operation, and maintenance of a pulverized fuel system should recognize certain inherent hazards, as outlined in A.9.3.2(1) through A (178). (1) An uninterrupted, controllable, raw fuel supply is essential to minimize fires and explosions within the system. Interruptions and control problems in the fuel supply can be caused by worn equipment, excessive surface moisture, large or unusual fuel sizing, or foreign substances, including iron, wood, rags, excelsior, or rock. Compositions of certain clays (i.e., Bentonitic or mixed layers), which are contained in some coal seams, can cause interruptions in coal flow.

336 Page 564 of 595 (2) The purchaser or the purchaser's designated representative should be aware of the wide range in material-handling characteristics of fuel that are related to differences in moisture, size distribution, and consolidation characteristics. The probable range in these characteristics for the fuels to be used and a determination of time consolidation shear values over these ranges are prerequisites for obtaining a bunker design that provides the desired flow characteristics over the range of fuels to be used. If the fuel is of a nature in which spontaneous combustion in the raw fuel bunker is likely to occur even when equipment is in service, the bunker design should be a mass flow design. (3) A fire that is ahead of or in the pulverizer usually causes an abnormal increase in temperature of the equipment or of the mixture leaving the pulverizer. Fires are caused by feeding burning fuel from the raw fuel bin; by spontaneous combustion of an accumulation of fuel or foreign material in the pulverizer, piping, or burners; or by operating at abnormally high temperatures. (4) Fires in burner pipes or other parts of pulverized fuel systems after the pulverizer generally will not be detected by an abnormal increase in pulverizer outlet temperature. Temperature sensors on pipes or in or on other components of the system can be used to detect these fires. (5) Abnormally hot, smoldering, or burning raw fuel that is ahead of the pulverizer should be considered serious and should be dealt with promptly. (6) Transport air is used to convey pulverized fuel from the pulverizer through pipes. Malfunction or maloperation introduces several hazards. For example, incorrect procedural steps for removing a burner from service will cause settling of pulverized fuel in the burner pipes. Leakage of pulverized fuel from an operating pulverizer through the burner valve into an idle burner pipe will cause pulverized fuel to settle in the burner pipe. Leakage of gas or air through a burner valve will increase the potential for fire in an idle pulverizer. Procedures to prevent such hazards are defined in Chapter 6. (7) Pulverizers that are tripped under load will have fuel remaining in the hot pulverizer, burner piping, and burners. These accumulations increase the potential for spontaneous combustion or explosion of the fuel. (8) Fuel systems are hazardous when fuel escapes into the surrounding atmosphere or when air enters an inerted system. (9) Oxidation of fuel has the potential to raise the temperature to a point where autocombustion or spontaneous combustion occurs. This characteristic constitutes a special hazard with certain fuels and fuel mixtures. (10) Accumulations of fuel in the pulverizer increase the potential for fires. Causes of fuel accumulation include but are not limited to design, conditions of wear, and insufficient drying, indicated by too low a pulverizer outlet mixture temperature. (11) Excessive pulverizer outlet mixture temperatures increase the possibility of pulverizer fires and increase the potential for fuel accumulation on burner parts. (12) Gases are released from freshly crushed fuel. Accumulations of flammable or explosive mixtures occur in bins or other enclosed areas. (13) Hot air flowing back into the fuel bunker constitutes a hazard.

337 Page 565 of 595 (14) To ensure compatibility of the type of fuel to be pulverized, a quality definition of the fuel is required. The equipment designer, the agency responsible for procurement of the fuel, and the operating department should use this definition. Volatility, moisture, ash content, maximum size and distribution, grindability, corrosiveness, abrasiveness, and other characteristics should be given close attention. (15) A pulverized fuel system is designed for a specific range of fuel characteristics. Fuels that differ widely from the design range increase the risk of serious operating difficulties and produce a potential safety hazard. Procedures should be exercised to make sure that all received fuels are within the specific range of the fuel-handling and fuel-burning equipment. (16) Insufficient personnel training, incomplete maintenance programs, and operation of excessively worn equipment increase the potential for fires and explosions. (17) Accumulation of pulverized fuel in air ducts or pipes, particularly those shared by a group of pulverizers, is hazardous. (18) There are different types of instruments and controls that can be installed to monitor and control conditions in the pulverized fuel system. Care should be taken to select and install these devices to prevent abnormal and hazardous conditions, and to coordinate the installation of such devices with the pulverized fuel system designer. Readily operable remote control dampers and valves in the ductwork and the necessary instrumentation for their automated control should be installed, operated, and maintained in accordance with the instrument or control manufacturer s instructions and good engineering practice. (See also Section 6.8.) A Some parts of the pulverized fuel system, such as large flat areas and sharp corners, can be subjected to shock wave pressures. A This ductwork is exposed to explosion pressures from the pulverizer in the event of an explosion. A See NFPA 68, Standard on Explosion Protection by Deflagration Venting. A Operation with burner(s) out of service. Operation of the pulverizerburner system with less than the full complement of burners served by a pulverizer, unless the system is designed specifically for such operation, creates the potential for fires and explosion. If not so designed, extra precautions should be used in isolating out-of-service burners. A Some applications utilize auxiliary air dampers to maintain burner line velocities at or above minimum to transport the fuel without settling. Supplemental Information File Name Description New_Chapter9_AnnexA_Rev1.docx

338 A Use of fuel blends with individual fuels having less than 8 percent volatility on a moisture-free basis should be discussed fully with the manufacturer. A Pulverizing and fuel system component functions include the following: (1) (2) (3) (4) Drying and conveying of fuel. Pulverizer air is used to continuously convey the pulverized fuel from the pulverizer. Normally, heated pulverizer air evaporates some of the moisture from the raw fuel while it is being pulverized, and it elevates the air-fuel mixture to the desired temperature. The temperature and quantity of pulverizer air that is used are controlled to obtain the desired degree of dryness and pulverizer outlet temperature, depending on the type of fuel being burned. Classifying the pulverized fuel. An essential characteristic of the pulverized product is its fineness. It is desirable that the pulverized fuel system minimize variation in fineness, because pulverizer parts exhibit wear and fuel properties change over the anticipated range. For this purpose, most pulverizers are equipped with adjustable classifiers or achieve some adjustment of fineness by varying air flow or other means. Transporting and distributing the pulverized fuel. The pulverized fuel should be transported directly to one or more burners, to one or more air-fuel separation devices, or to one or more bins or lock hoppers for intermediate storage. Refuse removal. It is desirable that foreign, hard-to-grind material be removed from the fuel before it is fed to the pulverizers; however, it is advisable that the pulverizers either reject or tolerate reasonable amounts of such materials so that damage or interruption of service does not result. The refuse removal system should be designed to protect personnel from exposure to hot gases that are present in the pulverizer. This could be accomplished through the use of manual gates, isolation valves, operating procedures, or a combination thereof. A The design, operation, and maintenance of a pulverized fuel system should recognize certain inherent hazards, as outlined in A.9.3.2(1) through A.9.3.2(1817). (1) An uninterrupted, controllable, raw fuel supply is essential to minimize fires and explosions within the system. Interruptions and control problems in the fuel supply can be caused by worn equipment, excessive surface moisture, large or unusual fuel sizing, or foreign substances, including iron, wood, rags, excelsior, or rock. Compositions of certain clays (i.e., Bentonitic or mixed layers), which are contained in some coal seams, can cause interruptions in coal flow. (2) The purchaser or the purchaser's designated representative should be aware of the wide range in material-handling characteristics of fuel that are related to differences in moisture, size distribution, and consolidation characteristics. The probable range in these characteristics for the fuels to be used and a determination of time consolidation shear values over these ranges are prerequisites for obtaining a bunker design that provides the desired flow characteristics over the range of fuels to be used. If the fuel is of a nature in which spontaneous combustion in the raw fuel bunker is likely to occur even when equipment is in service, the bunker design should be a mass flow design.

339 (3) A fire that is ahead of or in the pulverizer usually causes an abnormal increase in temperature of the equipment or of the mixture leaving the pulverizer. Fires are caused by feeding burning fuel from the raw fuel bin; by spontaneous combustion of an accumulation of fuel or foreign material in the pulverizer, piping, or burners; or by operating at abnormally high temperatures. (4) Fires in burner pipes or other parts of pulverized fuel systems after the pulverizer generally will not be detected by an abnormal increase in pulverizer outlet temperature. Temperature sensors on pipes or in or on other components of the system can be used to detect these fires. (5) Abnormally hot, smoldering, or burning raw fuel that is ahead of the pulverizer should be considered serious and should be dealt with promptly. (6) Transport air is used to convey pulverized fuel from the pulverizer through pipes. Malfunction or maloperation introduces several hazards. For example, incorrect procedural steps for removing a burner from service will cause settling of pulverized fuel in the burner pipes. Leakage of pulverized fuel from an operating pulverizer through the burner valve into an idle burner pipe will cause pulverized fuel to settle in the burner pipe. Leakage of gas or air through a burner valve will increase the potential for fire in an idle pulverizer. Procedures to prevent such hazards are defined in Chapter 6. (7) Pulverizers that are tripped under load will have fuel remaining in the hot pulverizer, burner piping, and burners. These accumulations increase the potential for spontaneous combustion or explosion of the fuel. (8) Fuel systems are hazardous when fuel escapes into the surrounding atmosphere or when air enters an inerted system. (9) Oxidation of fuel has the potential to raise the temperature to a point where autocombustion or spontaneous combustion occurs. This characteristic constitutes a special hazard with certain fuels and fuel mixtures. (10) Accumulations of fuel in the pulverizer increase the potential for fires. Causes of fuel accumulation include but are not limited to design, conditions of wear, and insufficient drying, indicated by too low a pulverizer outlet mixture temperature. (11) Excessive pulverizer outlet mixture temperatures increase the possibility of pulverizer fires and increase the potential for fuel accumulation on burner parts. (12) Gases are released from freshly crushed fuel. Accumulations of flammable or explosive mixtures occur in bins or other enclosed areas. (13) Hot air flowing back into the fuel bunker constitutes a hazard. (14) To ensure compatibility of the type of fuel to be pulverized, a quality definition of the fuel is required. The equipment designer, the agency responsible for procurement of the fuel, and the operating department should use this definition. Volatility, moisture, ash content, maximum size and distribution, grindability, corrosiveness, abrasiveness, and other characteristics should be given close attention.

340 (15) A pulverized fuel system is designed for a specific range of fuel characteristics. Fuels that differ widely from the design range increase the risk of serious operating difficulties and produce a potential safety hazard. Procedures should be exercised to make sure that all received fuels are within the specific range of the fuel-handling and fuel-burning equipment. (16) Insufficient personnel training, incomplete maintenance programs, and operation of excessively worn equipment increase the potential for fires and explosions. (17) Accumulation of pulverized fuel in air ducts or pipes, particularly those shared by a group of pulverizers, is hazardous. (18) There are different types of instruments and controls that can be installed to monitor and control conditions in the pulverized fuel system. Care should be taken to select and install these devices to prevent abnormal and hazardous conditions, and to coordinate the installation of such devices with the pulverized fuel system designer. Readily operable remote control dampers and valves in the ductwork and the necessary instrumentation for their automated control should be installed, operated, and maintained in accordance with the instrument or control manufacturer s instructions and good engineering practice. (See also Section 6.8.) A.9.3.2(5) In any section of an indirect-fired system that operates under negative pressure, it is important to minimize ambient air entering the system, where it could develop a flammable mixture. A The requirement does not exclude the use of water-based solutions, such as wetting agents, fire extinguishing agents, or surfactants. The use of water alone creates steam, thereby introducing a secondary personnel hazard. A The use of the coal column is a common method for preventing the air or gas from backflowing into the bunker. By preventing this backflow, the coal inherently absorbs excessive pressure resulting from an explosion and prevents any flame front from an explosion from propagating into the bunker. It is understood that the coal does not entirely stop backflow of air, but it has been proven effective in protecting the feeder and the bunker. A P max is defined as the maximum pressure developed in a contained deflagration for an optimum mixture. A P max of 7 bar-g was obtained from ASTM E 1226, Standard Test Method for Explosibility of Dust Clouds, for bituminous coal. However, the particle size in ASTM E 1226 is significantly smaller than that produced by pulverizers in the scope of NFPA 85. Therefore, a P max of 10 bar-g was chosen to represent typical conditions for equipment covered by NFPA 85. Using the calculation method in NFPA 69, Standard on Explosion Prevention Systems, the maximum allowable working pressure (MAWP) associated with a P max of 10 is shown to be approximately 344 kpa (50 psi) or less for operating pressures of 13.8 kpa (2 psi) or less. When determining the P mawp to contain the deflagration, the calculated minimum design value for P mawp will be less than the actual peak pressure expected during the deflagration. Deflagration is a short-term pressure excursion, and this method is recognized in ASME Boiler and Pressure Vessel Code. The formulas are based on a paper by Noronha et al. See NFPA 68,

341 Standard on Explosion Protection by Deflagration Venting, for a more detailed description of the forces imposed during a deflagration. [69:A ] A A Some parts of the pulverized fuel system, such as large, flat areas and sharp corners, can be subjected to shock wave pressures. A A This ductwork is exposed to explosion pressures from the pulverizer in the event of an explosion. A P max is defined as the maximum pressure developed in a contained deflagration for an optimum mixture. A P max of 7 bar-g was obtained from ASTM E 1226, Standard Test Method for Explosibility of Dust Clouds, for bituminous coal. However, the particle size in ASTM E 1226 is significantly smaller than that produced by pulverizers in the scope of NFPA 85. Therefore, a P max of 10 bar-g was chosen to represent typical conditions for equipment covered by NFPA 85. Using the calculation method in NFPA 69, Standard on Explosion Prevention Systems, the maximum allowable working pressure (MAWP) associated with a P max of 10 is shown to be approximately 344 kpa (50 psi) or less for operating pressures of 13.8 kpa (2 psi) or less. When determining the P mawp to contain the deflagration, the calculated minimum design value for P mawp will be less than the actual peak pressure expected during the deflagration. Deflagration is a short-term pressure excursion, and this method is recognized in ASME Boiler and Pressure Vessel Code. The formulas are based on a paper by Noronha et al. See NFPA 68, A Some parts of the pulverized fuel system, such as large, flat areas and sharp corners, can be subjected to shock wave pressures. A If the expanded gases from a deflagration cannot flow freely into the furnace, the piping should be designed for elevated pressures or the pressure should be limited by other mitigation techniques in accordance with NFPA 69, Standard on Explosion Prevention Systems. See NFPA 68, Standard on Explosion Protection by Deflagration Venting, for a more complete treatment of the effects of pressure piling. A The requirement does not exclude the use of water-based solutions, such as wetting agents, fire extinguishing agents, or surfactants. The use of water alone creates steam, thereby introducing a secondary personnel hazard. A P max is defined as the maximum pressure developed in a contained deflagration for an optimum mixture. A P max of 7 bar-g was obtained from ASTM E 1226, Standard Test Method for Explosibility of Dust Clouds, for bituminous coal. However, the particle size in ASTM E 1226 is significantly smaller than that produced by pulverizers in the scope of NFPA 85. Therefore, a P max of 10 bar-g was chosen to represent typical conditions for equipment covered by NFPA 85. Using the calculation method in NFPA 69, Standard on Explosion Prevention Systems, the maximum allowable working pressure (MAWP) associated with a P max of 10 is shown to be approximately 344 kpa (50 psi) or less for operating pressures of 13.8 kpa (2 psi) or less. When determining the P mawp to contain the deflagration, the calculated minimum design value for P mawp will be less than the actual peak pressure expected during the deflagration.

342 Deflagration is a short-term pressure excursion, and this method is recognized in ASME Boiler and Pressure Vessel Code. The formulas are based on a paper by Noronha et al. See NFPA 68, A Some parts of the pulverized fuel system, such as large, flat areas and sharp corners, can be subjected to shock wave pressures. A This ductwork is exposed to explosion pressures from the pulverizer in the event of an explosion. A Some parts of the pulverized fuel system, such as large, flat areas and sharp corners, can be subjected to shock wave pressures. A A See NFPA 68, Standard on Explosion Protection by Deflagration Venting. A If the expanded gases from a deflagration cause pressure piling in downstream piping or equipment, the piping or equipment should be designed for elevated pressures or the pressure should be limited by other mitigation techniques in accordance with NFPA 69, Standard on Explosion Prevention Systems. See NFPA 68, Standard on Explosion Protection by Deflagration Venting, for a more complete treatment of the effects of pressure piling. A In systems using highly-reactive fuel, such as Powder River Basin (PRB) coal, users and designers should consider inerting during start-up and shutdown to minimize the risk of pulverizer fires during these transitional sequences. A A Operation with burner(s) out of service. Operation of the pulverizerburner system with less than the full complement of burners served by a pulverizer, unless the system is designed specifically for such operation, creates the potential for fires and explosion. If not so designed, extra precautions should be used in isolating out-of-service burners. A A Some applications utilize auxiliary air dampers to maintain burner line velocities at or above minimum to transport the fuel without settling. A In systems using highly-reactive fuel, such as Powder River Basin (PRB) coal, users and designers should consider inerting during start-up and shutdown to minimize the risk of pulverizer fires during these transitional sequences. A In systems using highly-reactive fuel, such as Powder River Basin (PRB) coal, users and designers should consider inerting during start-up and shutdown to minimize the risk of pulverizer fires during these transitional sequences.

343 Page 566 of 595 Submitter Full Name: [ Not Specified ] Organization: [ Not Specified ] Submittal Date: Tue Mar 05 17:37:39 EST 2013 The annex text is renumbered to be consistent with FR 150 and new annex text is added to clarify new requirements.

344 FR 226 Annex E

345 Annex E Fluidized Bed Boilers Supplemental Information This annex is not a part of the requirements of this NFPA document but is included for informational purposes only. E.1 Terminology. The following terms are specific to fluidized bed boiler applications. E.1.1 Agglomerating. A characteristic of coal that causes coking on the fuel bed during volatilization. E.1.2 Air. E Primary Air (in a Bubbling Fluidized Bed). That portion of total air used to transport or inject fuel or sorbent and to recycle material to the bed. E Primary Air (in a Circulating Fluidized Bed). That portion of total air introduced at the base of the combustor through the air distributor. E Secondary Air (in a Bubbling Fluidized Bed). That portion of the air introduced through the air distributor. E Secondary Air (in a Circulating Fluidized Bed). That air entering the combustor at levels above the air distributor. E Transport Air (in a Fluidized Bed). The air used to convey or inject solid fuel or sorbent or to recycle material. E.1.3 Atmospheric Fluidized-Bed Combustion. A fuel-firing technique using a fluidized bed operating at near-atmospheric pressure on the fire side. E.1.4 Auxiliary Load-Carrying Burner. In a fluidized bed boiler, a burner whose primary purpose is load carrying, that is located over the bed, and that has its own air supply. E.1.5 Over Bed Burner. In a fluidized bed boiler, a warm-up burner located above the bed and firing over or into the bed. E.1.6 Elutriation. The selective removal of fine solids from a fluidized bed by entrainment in the upward flowing products of combustion. E.1.7 Hogged Fuel. Wood refuse that has been chipped or shredded by a machine known as a hog. E.1.8 Main Fuel Temperature Permit. The minimum fluidized bed temperature at which the main fuel can be introduced with resulting stable combustion. E.1.9 Minimum Fluidization Velocity. In a fluidized bed, the lowest velocity sufficient to cause incipient fluidization. E.1.10 Recirculation (Solids or Recycle). The reintroduction of solid material extracted from the products of combustion into a fluidized bed.

346 E.1.11 Recycle Rate. In a fluidized bed, the rate at which a mass of material is reinjected into the bed. This value is often expressed as the ratio of the amount being reinjected to the total amount being elutriated from the fluidized bed. E.1.12 Recycle Ratio. In a fluidized bed, the mass of material being reinjected into the bed divided by the mass of fuel being fed into the bed. E.1.13 Reinjection. In a fluidized bed boiler, the return or recycling of material removed or carried from the furnace back to the furnace. Also refers to fly ash collected and returned to the furnace or combustion chamber, sometimes expressed as a percentage of the total collected. E.1.14 Spent Bed Material. In a fluidized bed boiler, material removed from the bed generally comprising reacted sorbent, calcined limestone, ash, and solid, unburned combustibles. For some applications, the spent bed material might also contain some inert material, such as sand. E.2 Annex H Guidelines for Determining the Minimum Permitted Temperature for Feeding a Fuel into a Fluidized Bed. Formatted: Font: Bold H.1 E.2.1 Scope. This method describes a procedure for establishing the minimum fluid bed temperature at which a fuel ignites and sustains controllable combustion. The test approaches described in Section H.3E.2.3 and Section H.4E.2.4 are typical approaches followed by manufacturers to assist in design activities for this equipment. The test method described in Section H.5E.2.5 is an important boiler commissioning activity performed on each new unit by the manufacturer and observed by other interested parties. H.2 E.2.2 General Consideration. The purpose of this recommended procedure is to establish an initial minimum temperature permissive above which fuel can be fed into the fluidized bed. This initial temperature permissive should be verified by tests in the full-scale plant. This procedure can be used by the fluidized bed combustor (FBC) supplier to determine the minimum fluidized bed temperature at which fuel can be fed into the furnace. The FBC supplier can use this temperature for defining the fuel permissive safety system for both startup and hot restart. The FBC supplier and operator should be aware of the following concerns and cautions: (1) Pilot test information can differ from full-scale unit operation. The supplier should be aware of such differences and include a safety margin based on actual experience. (2) Typically, there is a time delay between fuel feed command and fuel entering the furnace. This is reflected in a decrease in temperature of the fluidized bed material during the period between bed fluidization and the arrival of the fuel in the bed. Bed cooling during this delay period could cause the temperature to fall below the fuel feed permissive. (3) The minimum bed temperature at which fuel ignites and causes the bed material and freeboard temperature to increase is likely to be dependent on the air velocities, the air-

347 fuel ratio, and the heat extraction surfaces within the combustion zones. The FBC supplier should consider the effect of these factors for both cold start-up and hot restart operation of the FBC. (4) During initial plant start-up, the temperature permissive for fuel flow is usually verified in the installation. This test might show that a higher permissive fluidized bed temperature is necessary to ignite the fuel. The supplier anticipates this possibility by providing the means for heating the bed to a higher temperature than that indicated by the pilot combustion tests. H.3 E.2.3 Test Setup and Measurements. H.3.1 E Pilot Test Setup and Measurements. The test should use a pilot fluidized bed combustion system that simulates the supplier's full-scale equipment. As a minimum, the test should include the following: (1) A fuel feed system with feed rate control and feed rate monitor. (2) Air controls and measurements of the fluidizing air, fuel transport air, and secondary air as applicable. (3) Thermocouples to monitor the temperatures of the incoming airstreams, the bed temperature and freeboard temperature, and the temperature of the combustion products exhausting the freeboard. (4) Recording instruments that provide a record of the fluidized bed and freeboard temperatures. The printout scale and speed should be adjustable to provide a clear history of time and temperatures. (5) Bed material that simulates the size distribution and material density projected for the fullscale system. (6) Solid fuel that is representative of samples of the design fuels. Control should be exercised to ensure that fuel moisture content and size are properly simulated. If dictated by the pilot unit restrictions for maximum fuel size, the oversized fraction of fuel can be removed from the test feedstock, or the maximum fuel size can be reduced by means of additional processing. (7) Equipment to allow heat extraction from the fluidized bed or furnace freeboard, as appropriate, to simulate the supplier's equipment design. (8) A pilot test device that is rated at a minimum throughput capacity of 293 kw t (1 million Btu/hr). H.3.2 E Bench-Scale Flammability Test Setup. An alternate means of establishing an initial minimum ignition temperature by test is through the use of conventional ignition or flammability tests. The intent of these tests is not so much to establish directly a minimum ignition temperature, but rather to allow the manufacturer to extrapolate an ignition temperature based on the results of a given test and similar tests on fuels fired at other actual installations. The correlation between the ignition temperature (flammability index) yielded by tests of various fuels at an actual plant and the verified minimum ignition temperature established for

348 that plant and the results of the testing performed on the unknown fuel are sufficient to yield an initial set point for the unknown fuel. As a minimum, the following should be used for the test: (1) A furnace with a controllable heat source (2) Thermocouples to monitor the temperature of the furnace (3) Representative samples of the fuel to be fired (The samples should be prepared in accordance with normal procedures for the test setup to be utilized.) The intent is not to require any specific test but rather to use the same test on multiple fuel samples to establish a relationship between the unknown fuel and its appropriate minimum ignition temperature based on the relationship of other known fuels and their proven ignition temperatures. H.4 E.2.4 Test Procedure. The proposed test procedure is a repetitive process that incrementally reduces the bed temperature until the system fails the success criteria for fuel ignition and sustained combustion. A fuel might have a very low temperature for ignition and sustained combustion, possibly one that is considerably lower than the operating bed temperature range of interest. Where such fuel is used, the FBC equipment supplier may be permitted to terminate the tests after they demonstrate successful operation at a temperature lower than the proposed minimum ignition temperature. H.4.1 E Test Operation. H E Pilot Test Operation. H E With fans operating, the FBC test unit should be stabilized at 56 C to 111 C (100 F to 200 F) above the minimum bed temperature at which the fuel is known to sustain combustion. Verification of instrument operation and calibration should be made, and operating conditions should be adjusted to the selected air velocity excess air and bed temperature. Fuel flow, airflows, and temperatures should be monitored and recorded. H E The fuel should be shut off, and the bed temperature should be allowed to fall. The fuel feed conveying and metering equipment should be kept primed to minimize the fuel delivery delay time at fuel restart. At 28 C (50 F) below the previously demonstrated temperature for sustaining combustion, the fuel flow should be resumed at the rate used in H E for a maximum of 90 seconds. H E In a successful test, the temperature responses of the bed and freeboard are to be smooth and are to indicate a reversal of the fluidized bed and freeboard temperature gradients. If the success criteria are met, E H through E H should be repeated at successively lower temperatures. If the success criteria are not met, the test should be terminated and a postpurge completed. H E Minimum Permitted Bed Temperature. The minimum permitted bed temperature for admitting fuel flow into the fluidized bed should be not less than the minimum temperature at which success was achieved in E H

349 H.4.2 E Bench-Scale Flammability Test. H E Test Procedure. H E The test furnace should be stabilized at 56 C to 111 C (100 F to 200 F) above the expected ignition temperature of the fuel. H E A fuel sample should be admitted. H E If the fuel ignites, the test should be repeated after reducing the temperature of the furnace. H E If the fuel fails to ignite, the test should be terminated. The ignition temperature of the fuel is the last value that satisfies H E H E Minimum Permitted Bed Temperature. The initial minimum fuel permissive is determined by correlating the results of the tests of the unknown fuel sample with similar tests performed for fuels used in other units of similar design and the corresponding minimum ignition temperatures established for those fuels in the respective units. It should be noted that this procedure, as in the procedure described in H.4.1.1E , has a degree of uncertainty, and appropriate safety margins should be implemented until the testing on the actual unit can be completed. H.5 E.2.5 Verifying Minimum Temperature at Actual Plant. The FBC supplier and the operator should agree to a procedure similar to that described in H.4.1.1E for verifying a minimum bed temperature for fuel flow start in the full-scale plant. A margin of safety should be added to any value derived through test. Where fuel sources change the minimum temperature, the test should be repeated. E.3 Annex L Personnel Hazards of Atmospheric Fluidized Bed Boilers. L.1 E.3.1 Special Hazards in Fluidized Bed Combustion (FBC) Systems. A number of personnel hazards are associated with fluidized bed combustion. FBC boilers differ from conventional boilers in important features. Some of these differences can lead to special hazards, several of which are included in the following discussion. These hazards include large quantities of hot, solid materials, significant concentrations of reactive compounds in the solids, and hazardous gaseous species. Extensive treatment of these special hazards is beyond the scope of this code. Because FBC technology is still relatively new, recognition of these hazards is warranted. The boiler manufacturer, the plant designer, and the operator have responsibility for mitigating these hazards to the extent practicable. L.2 E.3.2 Hot Solids. L.2.1 E Description of Hazard. FBC systems contain large quantities of granular solids. A typical 100 MW t (341 million Btu/hr) FBC boiler can contain as much as 91 metric tons (100 tons) of free-flowing solids at 815 C (1500 F) or higher. These hot solids can spill out of the furnace or other components because of equipment failures, poor design, or misoperation. There

350 have been several such incidents in operating plants. In the event of uncontrolled hot-solid spills, personnel can be injured, equipment damaged, or both. L.2.2 E.3.2 Recommendations. Recommendations are as follows: (1) The designers of the boiler and related plant equipment should identify the potential sources of hot solids and associated hazards and make recommendations for personnel safety. (2) The designer should give careful consideration to the selection of materials that come into direct contact with hot solids. (3) Clean-out ports, fittings that might be used as clean-out ports, and spool pieces that might be removed for rodding out blockages should be positioned so that a sudden rush of hot solids does not lead to personnel injury. Components that are removable for maintenance when the plant is out of service but that should not be removed when the plant is in service because of the risk of hot spills should be marked clearly. (4) Instrumentation and wiring needed for the safe operation of the plant should not be routed near potential sources of hot solids. If such routing is necessary, the wiring should be protected from the direct flow of the solids. (5) Fuel lines should not be located near potential sources of hot solids. The fuel lines should be protected from the direct flow of the solids. (6) Plant personnel should be trained in the potential sources of hot solids, associated hazards, and the corresponding safety procedures. (7) Procedures should be developed for cleaning obstructions that provide safety to personnel and equipment. Protective clothing and eye protection should be provided for personnel who rod out obstructions. (8) Components that might contain hot solids should be inspected frequently. (9) Water-cooled screws have failed when suddenly flooded with hot bed material following the removal of an upstream blockage. The sudden transfer of large amounts of heat has resulted in overpressurizing the cooling water passages. The operators should be trained adequately and the systems designed with appropriate instrumentation, interlocks, and pressure relief devices to mitigate the risks associated with this type of event. (10) An FBC system's furnace and connected components will contain substantial quantities of hot solids for some time after a master fuel trip (MFT). Personnel should be aware of and trained to deal with the following possible results: (a) Hot solids stored in a furnace-connected space may suddenly flow into another space. Care should be taken to ensure that personnel do not enter a furnace or connected space that could still contain hot solids or be connected to a space that contains hot solids. (b) Solids stored in the cyclone or loop seal for example, due to blockage could suddenly be released and flow into another space when the blockage fails or the solids cool and their fluidization characteristics change. (c) Operation of an FD fan, an ID fan, or other fans might not rapidly cool stored solids because the moving air could bypass the bulk of a heap of hot particles.

351 (d) While a surface could appear cool because of rapid heat loss due to radiation, the bulk of the heap could still be hot due to self-insulation. A large heap of solids could require many hours to cool to a safe temperature. (e) Water might enter a body of hot solids from any of a number of sources, including a boiler tube leak. Water pouring onto the solids might not immediately wet the hot solids (much like a drop of water on a hot griddle). When the solids suddenly become wet, rapid generation of steam (steam explosion) could occur. In the event of a steam explosion, hot solids could flow upward as well as in other directions. (f) Large hot clinkers or hot refractory could suddenly be released from the cyclone and flow into the loop seal and connected spaces with the assistance of smaller fluidizable particles. L.3 E.3.3 Lime. L.3.1 E Description of Hazard. Limestone is normally fed to fluidized bed boilers to reduce the emissions of sulfur dioxide. More limestone should be added to comply with emission limits than is theoretically needed to react with all the fuel's sulfur. A significant amount of the limestone is not converted to calcium sulfate and exists as calcium oxide, commonly referred to as quicklime. Where calcium oxide (CaO) is present in the solids, care should be used to prevent equipment damage or injury to personnel. CaO reacts with water or water vapor to generate heat and reacts with moisture on skin or eyes to cause chemical burns. L.3.2 E Recommendations. Recommendations are as follows: (1) Where limestone is used as an initial bed charge, it is quickly calcined to CaO (quicklime) before a large fraction reacts to CaSO 4. In some instances where limestone has been used for the initial charge, personnel have experienced chemical burns when entering the furnace because the limestone had turned to quicklime. Because of the likelihood that, during initial plant start-ups, a number of plant problems necessitate that personnel enter the FBC, the boiler manufacturer should recommend that the initial charge of bed material comprise sand, coal ash, or other chemically inert material rather than limestone. (2) Where three parts lime are wet with approximately one part water, the highest temperature is reached due to a chemical reaction. Where the reaction of pure, reactive lime occurs within a large volume (providing insulation), temperatures of about 315 C (600 F) can be reached. This temperature is sufficiently high to ignite paper, for example, which in turn could lead to a plant fire. Also, equipment designed for ambient temperature and pressure can fail when heated by a large lime-water reaction. Therefore, relevant plant components should be designed to perform safely at high temperatures, and means of avoiding pressure buildup should be provided. Provisions should be made for detecting high temperatures within tanks and other components. (3) Waste-conditioning systems do mix FBC wastes with water. The designers of these components should be made aware of the likelihood and effects of lime-water reactions by the system integrator, normally an architect, an engineer, or the plant owner. (4) While the plant is in service, lime-water reactions could occur in so-called dead zones due to the humidity in air or flue gas. These reactions might or might not lead to particularly high

352 temperatures, but they often do lead to hard blockages. These blockages might disable safety instrumentation, ash removal systems, or other components. Designers should anticipate this problem and provide a means to detect the presence of blockages, especially in instrument lines, as well as a means to remove blockages safely. (5) The safety equipment necessary for dealing with lime should be provided, including breathing masks, protective clothing, and eye protection. First-aid facilities for chemical burns, especially of eyes, should be provided. Operators should be trained to test for the presence of quicklime before entering an enclosure filled with solids. One simple test can be performed by sampling the solids. The sample is placed in a metal (not glass) container by a person wearing gloves and eye protection. An approximately equal volume of water is added, the solution is stirred, and approximately 15 minutes is allowed to pass in order to detect a temperature rise. L.4 E.3.4 Hydrogen Sulfide. L.4.1 E Description of Hazard. Fluidized bed boilers that operate substoichiometrically in the lower combustion zone can produce hydrogen sulfide (H 2 S) as an intermediate product before the sulfur is fully oxidized. Because of the positive pressure in the lower combustion zone, H 2 S can leak out of the furnace and into an area where personnel are working. Hydrogen sulfide is heavier than air and concentrates in poorly ventilated low points in the plant, creating the potential for personnel injury. L.4.2 E Recommendations. Recommendations are as follows: (1) Adequate seals or gaskets on components that can be opened or disassembled and that are located in the dense bed region should be provided. Weld components that do not need to be opened or disassembled should be sealed. (2) Written guidelines on H 2 S should be provided with the equipment manuals. (3) Operators should be trained to anticipate the presence of H 2 S. (4) Means for measuring the concentration of H 2 S in the boiler house and other plant facilities should be provided. L.5 E.3.5 Calcium Sulfide. L.5.1 E Description of Hazard. The bottom ash (and under some modes of misoperation, fly ash) from a fluidized bed boiler could contain some calcium sulfide, which is a reaction product of H 2 S with limestone in the absence of sufficient oxygen. Calcium sulfide can react with CO 2 and H 2 O, which are constituents of air, and release H 2 S. If this occurs in a waste storage silo, for example, the silo's environment can reach a hazardous concentration of H 2 S. L.5.2 E Recommendations. Recommendations are as follows: (1) Operators should be trained for the possibility that calcium sulfide in FBC waste products could lead to the release of H 2 S in waste storage silos and piles. (2) Operators should be trained in the proper procedures for entry of enclosed spaces.

353 Page 582 of 595 The Fundamentals committee deleted many definitions specific to fluidized bed boilers from chapter 3 because the terms are not used in the mandatory text. The Fluidized Bed Boiler committee relocated these definitions to a new Annex E, which is also combined with the text of existing annexes H and L so that all FBB supplemental information will be found in one annex.

354 Page 583 of 595 First Revision No. 244-NFPA [ Chapter E ] Annex F Common Pulverized Fuel System Designs F.1 Direct-Fired Pulverized Fuel Systems. F.1.1 Common designs for direct-fired pulverized fuel systems, as shown in Figure F.1.1(a) through Figure F.1.1(f), are permitted to have the fan located either following or ahead of the pulverizer. Figure F.1.1(a) Direct-Firing Pulverized Fuel Exhauster System for Suction Furnace. Figure F.1.1(b) Direct-Firing Pulverized Fuel Hot Primary Air Fan System for Suction Furnace. Figure F.1.1(c) Direct-Firing Pulverized Fuel Exhauster System for Positive Pressure Furnace.

355 Page 584 of 595 Figure F.1.1(d) Direct-Firing Pulverized Fuel Hot Primary Air Fan System for Pressure Furnace. Figure F.1.1(e) Direct-Firing Pulverized Fuel Cold Primary Air Fan System for Pressure Furnace. Figure F.1.1(f) Direct-Firing Pulverized Fuel Cold Primary Air Fan System for Suction Furnace. F.2 Indirect-Firing Pulverized Fuel Systems. F.2.1 Common designs for indirect-firing systems, as shown in Figure F.2.1(a) through Figure F.2.1(h), are arranged to permit partial or complete venting of the pulverizer air and water vapor after separating the pulverized fuel in cyclones or other types of dust collectors. Figure F.2.1(a) Pulverized Fuel Indirect-Firing System.

356 Page 585 of 595 Figure F.2.1(b) Pulverized Fuel Indirect-Firing System for Pressure Furnace. Figure F.2.1(c) Pulverized Fuel Indirect-Firing System: Partial Recirculation Vented Air to Stack. Figure F.2.1(d) Pulverized Fuel Indirect-Firing System: Partial Recirculation Vented Air to Stack. Figure F.2.1(e) Indirect-Firing System: Partial Recirculation Vented Air to Primary Air Fan. Figure F.2.1(f) Indirect-Firing System: Partial Recirculation Vented Air to Furnace.