VMA Presentation Pressure Seal (MSS-SP-144) and ASME B Update Carlos E. Davila, PE March 2014

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1 VMA Presentation Pressure Seal (MSS-SP-144) and ASME B Update Carlos E. Davila, PE March 2014 CRANE FLUID HANDLING

2 Fugitive Emissions Update EPA has been reducing the allowable fugitive emissions on valves in the last few years. Due to the upcoming emission legislation, most refineries, chemical and process industry plants will have to monitor their emissions more closely New industry standards are being published or revised for type testing of valves to improve emissions in new valves Better valves and sealing element designs will be replaced during shut downs Many aspects will be addressed to insure tight and minimal emissions to comply with new legislation 2

3 Pressure Seal Valve Design History Valve pressure seal design was last included as Appendix A in the API 600 Standard, 10 th Edition, February, 1997 API 600 Appendix A covered gate valves both Style A and Style B, however, the industry used it for other valve types It addressed the design using both API 600 as well as ASME B16.34 wall thicknesses. The appendix was not included in the API 600/ISO cobranded document published as the 11 th Edition of API 600 API did not want to include the design in the 12 th edition published in 2009 as API 600 and not co-branded with ISO 3

4 Pressure Seal Valve Design History (Cont.) Requests for a published document continued and it was decided to approach ASME B16 for the possibility of including it in B Discussions within ASME B16 were held but decision was reached that it would not be added to their documents. The Manufacturers Standardization Society, MSS, was then approached for consideration in preparing a standard MSS agreed and it was placed in the TC 114, Steel Valves, agenda for development It was published as SP-144 with an edition date of

5 Bolted Bonnet Bolted Design Bonnet uses external nuts and bolts to compress the bonnet gasket. High pressure / temperature conditions can force the bonnet gasket seal apart, causing external leakage and fugitive emissions Typically not to be used Above Class 600 Gasket Leak Path Leak Path Typical Bolted bonnet design 5

6 Pressure Seal Pressure Seal Design Valves use the process pressures to compress the bonnet gasket This eliminates leak paths to the atmosphere preventing fugitive emissions Gasket Pressure Typical Pressure Seal design 6

Pressure Seal Design depends on pressure to creates a tight seal The draw bolts will need to be adjusted due to compression of gasket due to higher pressure.

7 Pressure Seal Design depends on pressure to creates a tight seal The draw bolts will need to be adjusted due to compression of gasket due to higher pressure. No Pressure Under Pressure Bonnet Draw Bolt Collar Segment Ring Ret Ring Gasket Body Bonnet Draw Bolt Collar Segment Ring Ret Ring Gasket Body Typical Pressure Seal design 7

8 Pressure Seal Typical Pressure Seal Nomenclature 8

9 MSS SP-144 Developed by MSS and published in 2013 Covers original requirements of appendix A in the 10 th edition of API 600, 1997 Standard covers construction requirements for steel and steel alloy valves Applies to Gate, Globe and check valves May be used in conjunction with other valve specific standards Includes parent standards in the Standard Practice 9

10 MSS SP-144 Parent standards include, API 594, Check Valves; Flanged, Lug, Wafer, and Butt-welding API 600, Steel Gate Valves- Flanged and Butt-welding Ends, Bolted Bonnets API 603, Corrosion-resistant, Bolted Bonnet Gate Valves Flanged and Butt-welding Ends API 623, Steel Globe Valves Flanged and Butt-welding Ends, Bolted Bonnets ASME B16.34, Valves-Flanged, Threaded, and Welded End Not intended to replace requirements of the parent valve standard except for modifications for pressure seal. 10

11 MSS SP-144 Sizes and Pressure Classes NPS 2 (DN 50) through NPS 50 (DN 1250) Classes 600, 900, 1500, 2500 and 4500 For parent valve standard, API 600 Covers two styles of pressure seal bonnet valves Style A valves in accordance with API 600, except modified with ASME B16.34 minimum wall thicknesses and smaller diameter seats and stems. Style B valves in accordance with API

12 MSS SP-144 For parent valve standard API 594 API 594 covers wafer single and dual plate valves as well as swing check valves Wafer valve can be provided without leak path to the atmosphere Swing check valves have bolted covers that can be modified to the pressure seal design Valve must meet wall thickness requirements Stems are not effected 12

13 MSS SP-144 For parent valve standard API 603 Valve must comply with all of the requirements of this parent standard No style A or B is covered For Parent valve standard API 623 Recently published by API Specifies stem diameters larger/different than API 600 Valve must comply with all of the requirements of this parent standard No style A or B is covered 13

14 MSS SP-144 Materials Body and bonnet shall be an ASME B16.34 Group 1, Group 2, or Group 3 material. Gasket material shall be the manufacturer s standard, but limited to ductile iron, soft steel, austenitic stainless steel, vermiculite or flexible graphite. Pressure seal bonnet retention/sealing combination shall be the manufacturer s standard based on a tested and proven design. Wetted metal part shall have a corrosion resistance at least equivalent to the valve body material. Adjustment bolting material shall be selected, or be coated, to provide continuous serviceability during the valve s service life. 14

15 MSS SP-144 Design For API 600 Style A gate valves Body and bonnet wall thickness shall conform to the requirements of ASME B Inside diameter of seat openings shall not be less than 90% of appendix A in B16.34 for valve NPS and pressure class. If wedge gate is used, a flexible wedge shall be furnished unless otherwise specified. Minimum stem diameters shall be per Table 1. 15

16 MSS SP-144 Design (Cont.) For API 600 Style B gate valves, double disc gate is not permitted, unless otherwise specified. API 600 gate valves require body and gate guide surfaces to minimize wear and ensure alignment during full travel in all orientations. Only ASME B16.34 Standard Pressure Class valves are covered. Body-to-bonnet joint design requires that seal force increase as internal pressure increases. Requires bolting adjustment mechanism to pre-compress gasket to allow standard production test to proceed 16

17 MSS SP-144 Design (Cont.) Designs utilizing segmental rings in body recess, Fig. 1, must meet bearing, shear and bending stress requirements, such as, For bearing stress at a location, Fig.1, body/segmental retaining ring contact, P c x A g /A ab K 1 S 10,500 Covers rules for retainers to secure bonnet/gasket sealing structures For bolted flange retainers, the cross section must meet ASME B16.34 For threaded retainers, thread shearing area must meet ASME B

18 MSS SP-144 Provisions in the valve design are required to allow the removal of the segmental retaining ring Marking Shall be per MSS SP-25 and the parent standard. For gates to API 600, marking shall include Style A or B as applicable 18

19 MSS SP-144 Typical dimensional nomenclature Fig.1-Typical segmental retaining ring pressure seal joint 19

20 Stems Style A Table 1: Minimum stem diameters for API 600 Gate valves style A 20

21 Stems Style B Minimum stem diameters for API 600 Gate valves style B 21

22 ASME B Edition Approved by the ASME B16 Committee and published on February 19, year cycle to align with B16.5 and B16.47 Increase the size range from NPS 24 to NPS 50 Added reference to ASME B16.47 for flanges due to size range increase Some materials changed groups or were deleted Casting ASTM A351 Gr. CF3 moved from group 2.3 to 2.1 Casting ASTM A351 Gr. CF3M moved from group 2.3 to 2.2 Casting ASTM A351 Gr. CF8C deleted from group

23 ASME B16.34 Proposed changes for the 2016 Edition Pressure ceiling values ASME B16 Case that offers an alternative ceiling pressure for B16.34 Group #3, Nickel Alloy materials. Can be applied to pressure-temperature ratings without violating the "deflection rule" Review material group alignment Review present groups for 316 and 316L materials B16 Case for ASME B16.34 valves from Unlisted Materials. Expanding to Cover Valves up to NPS 60 to match ASME B

24 Questions? Thank You

STANDARDS and SPECIFICATIONS

STANDARDS and SPECIFICATIONS ANSI (American National Standards Institute) ANSI B31.4 - Liquid petroleum transportation piping system. ANSI B31.4 - Gas transmission and distribution piping system. API (American Petroleum Institute)