To establish a standardized procedure for Class B foam application by engine companies.

Transcription

1 PURPOSE: DATE Reviewed June 27, 2013 SARASOTA COUNTY GOVERNMENT EMERGENCY SERVICES DIRECTIVE VOLUME #2 FIRE OPERATIONS NUMBER #223 CATEGORY RECOMMENDED OPERATING GUIDELINE SUBJECT Class B FOAM EQUIPMENT To establish a standardized procedure for Class B application by engine companies. CLASS B FOAM APPLICATION EQUIPMENT All hand line systems on engine companies shall be operated at 125 gpm with 150 foot of 1 ¾ line between the eductor and nozzle. Eductors shall be marked with their rated flow capacity (gpm) and required inlet pressure (psi) based upon this standardized system. Foam Eductors The department maintains two types of inline eductors for use on all engine companies. The Spumifer 95/120 and the Angus UNI 450. Both have similar operating characteristics. Spumifer 95/120 Eductor Rated capacity: 95 / 120 gpm Friction Loss: 25-35% Operating Pressure: 200 psi Angus Model UNI 450 Eductor Rated capacity: 120 gpm Friction Loss: 35% Operating Pressure: 200 psi CLASS B FOAM EQUIPMENT 1

2 Air Aspirating Nozzles For Class B blankets to be effective they MUST be properly aerated. The department standard for all engine companies is a snapon tube used with Akron Turbojet Model 1767 adjustable gpm nozzles. Akron Model 1767 Turbojet Nozzle with Foam Tube When operated at 125 gpm and a nozzle pressure of 100 psi, this nozzle arrangement will provide finished at a 12:1 expansion ratio. This rate of expansion works well in either interior or exterior operations; it affords a fair reach and resists effects of wind. Additional low/medium expansion nozzles are maintained in Special Ops 8. FOAM CONCENTRATE Our Class B can be used on hydrocarbon fires at a 3% eduction rate or on water soluble liquid fires at 6% (i.e., Ethanol or other polar solvents) Standard issue shall be Chemguard 363 3% AFFF / 6% AR AFFF (alcohol resistant aqueous film forming ). Mixing of this with any other type of concentrate prior to eduction must be avoided. Never mix Class A and Class B s. Never use Class B for Class A firefighting and vice versa Foam concentrate shall be deployed based upon the following schedule: All engine companies Squad 8 & 9 Station 8 (Foam Cache) 10 gallons 30 gallons 200 gallons RECOMMENDED APPICATION PROCEDURES 1. Nozzles and educators must be matched. Both must have the same rated gpm flow. 2. Deploy your 150 pre-connected 1 ¾ hoseline. 3. Break the hose line at the small pony section of hose near the pump panel and insert the inline eductor. 4. Attached the tube to the nozzle. 5. Set the pump pressure to 200 psi 6. Insert pickup-tube into container. 7. Open the nozzle and purge the line and establish flow prior to attack. 8. Apply in accordance with percentage and application rates discussed below. 9. A blanket may be applied by roll-over, rain drop, or by deflection of the stream off of a solid surface. Do not disrupt the blanket by directing any fire stream (water or ) CLASS B FOAM EQUIPMENT 2

3 directly into a finished blanket. Such action will disrupt vapor suppression and permit a possible re-ignition. 10. Re-apply periodically after extinguishment to ensure that vapor suppression is effective. Rule of thumb: If you do not have a visible blanket on top of the product, you do not have effective vapor suppression. Periodic re-application will be necessary due to drain down. 11. Verify effective blanketing with air monitoring. Using Class B Foam in Foam Pro systems Class B Foam shall not be used with the built in FoamPro system due to an inability to supply the proper percentages. Only inline proportioning systems identified above shall be used. EDUCTION PERCENTAGES, APPLICATION RATES The appropriate percentage of concentrate must be mixed with water to achieve desired results. FOAM EDUCTION RATES Fuel Type Eduction Rate Hydrocarbon Fuels Gasoline, Gasoline with less that 10% ethanol, diesel 3% fuel, kerosene, aviation gasoline, jet fuel Polar Solvents and Water Soluble Materials Gasoline with greater than 10% ethanol, ethanol, other 6% alcohols, ketones and water soluble liquids If, after starting an initial attack at 3%, you experience excessive splattering or spread of fuel with rapid breakdown of, assume the product is water soluble and increase to 6% eduction rate. Once concentrate has been educted into the fire stream to create a solution that solution must be applied to the fire at a gpm/square foot fire rate sufficient to achieve control. Hydrocarbon fire application rate is 0.10gpm/sq.ft., polar solvent fires application rate is 0.15gpm/sq.ft. APPLICATION RATE RULES OF THUMB 125 gpm Foam Line You can effectively fight 1250 sq.ft. Hydrocarbon fire at 3% 2 ½ to 3 minutes sq.ft. Water soluble fires at 6% 1 to 1 ½ minutes Ten gallons of concentrate will last CLASS B FOAM EQUIPMENT 3

4 APPLICATION TROUBLE SHOOTING Problem Inductor will not pick up concentrate Possible resolution - Most common cause is the gpm rate of the nozzle and eductor are not matched. Check that gpm setting at nozzle is set at appropriate setting (125 gpm for engine companies) - Check and adjust pump pressure. Required pump pressure is 200 psi. Slowly adjust pressure both up and down while water is flowing and observe pick-up tube for flow. - Shut down system, bleed off line and check the ball valve at the pick-up tube connection point to insure it is not stuck. - Check for the possibility of air leaks at the pick up tube connection. Not achieving fire control - If fire splatters and spreads, consider the product water soluble and increase eduction rate to 6% - Fire may exceed capacity of exist hose lines. Increase number of lines deployed. Fire goes out but reignites - Foam blanket and vapor suppression is being disrupted - Water soluble materials may be breaking down blanket, re-apply at 6% concentration - Look for third dimension of fire. Foam will not extinguish a falling stream of fuel. Consider dual attack with dry chemical agents MAINTENANCE OF FOAM EDUCTION EQUIPMENT Cleaning of equipment - After using this equipment, be sure all residue is removed by thoroughly flushing the eductor and nozzle with fresh water. Failure to clean the equipment properly will leave a residue that can render the eductor inoperable. Both manufacturers recommend that the system be flushed with a minimum of 15 gallons of fresh water through the pick-up tube and eductor system. Foam Concentrate Shelf Life The manufacturer s stated shelf life for the is 20 years PROVIDED it is maintained in the sealed original container. Therefore, opened and partial containers of Class B shall be removed from service and transferred to training use. DO NOT, open sealed 1 st line containers of for training purposes. Training is available through the training division. NFPA 11 does not require annual testing of concentrate provided it is maintained in its original, sealed container. CLASS B FOAM EQUIPMENT 4

5 APPLICATION RATES FOR LARGE FIRES These tables are intended to support large scale operations beyond the first due engine company. Required GPM Application = sq.ft. fire x rate Rate = 0.10 for hydrocarbons, 0.15 for polar solvents Per Minute Concentrate Needs = GPM application x Concentration Concentration = 0.03 for hydrocarbons, 0.06 for polar solvents HYDROCARBON FIRES 3% APPLICATION RATE 5 min 10 min Concentrate Gal/Min 20 min 30 min Fire Area (sq.ft.) GPM Required POLAR SOLVENT (WATER SOLUBLE) FIRES 6% APPLICATION RATE 5 min 10 min 20 min GPM Concentrate Required Gal/Min 30 min Fire Area (sq.ft.) CLASS B FOAM EQUIPMENT 5