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FOAM APPLICATION TECHNIQUES HOSTED BY THE Jefferson County Fire and Rescue Training Academy
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TACTICS DO NOT START A FOAM OPERATION IF YOU DO NOT HAVE ENOUGH FOAM. (The fire will not go out and you will just waist foam) *INSTEAD, ATTEMPT TO PROTECT EXPOSURES OR EVACUATE IF YOU HAVE AN ETHANOL FIRE, USE AR- FOAM IF AT A FIXED FACILITY, ASK THE PEOPLE THAT WORK THERE FOR HELP. (They are the experts with the product on fire.)
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OBJECTIVES TERMS HOW FOAM WORKS FOAM GENERATION TYPES OF FOAM APPLICATION RATES FOAM EQUIPMENT PRACTICAL EVOLUTION
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What is Foam? NFPA- 11 describes Foam as an aggregate of air filled bubbles and is lower in density than flammable liquids. Must be able to- –Flow Freely –Have a high resistance to heat –Fuel tolerance –Form a tough, cohesive blanket –Must hold water
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Smothering: prevents release of vapors Foam’s Extinguishing Characteristics Separating: creates a barrier between the fuel and fire Cooling: lowers temperature of the fuel
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Limitations of Foam Foam solution is 94%-97% water –Cannot be used on: Electrical fires Three Dimensional Fires Pressurized Gases Combustible Metals
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Kinds of Foam Protein Fluroprotein Film Forming Protein (FFFP) Aqueous Film Forming Foam (AFFF) Alcohol Resistant AFFF (ARFFF)
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Aqueous Film Forming Foam (AFFF) Good penetrating characteristics Can be used with non-aerating nozzles Spreads a vapor-sealing film over fuels Can be pre-mixed Can be mixed with antifreeze Good low temperature viscosity May be applied directly on fuel surface, applied indirectly, or used with subsurface injection
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Foam Delivery Systems In-Line Eductors Around the Pump Eductor Compressed Air Foam System By-Pass Line Eductor
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Most commonly used Attached to pump or at some point in the hose lay In-line Foam Eductors The foam concentrate inlet to the inductor must be no more than six feet above the surface of the liquid foam concentrate
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Venturi Principle in Eductors As water at a high pressure passes over a reduced opening, it creates a low pressure near the outlet side of the eductor The low pressure creates a suction which draws the foam concentrate into the water stream.
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REMEMBER MATCH NOZZLE TO EDUCTOR MAINTAIN 200 PSI INLET PRESSURE
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HYDRAULICS Back Pressure should not exceed 70% of inlet pressure Back Pressure=NP+FLH+FLE 250’ of 1.75” and 0’ elevation –FLH= 100 + 30psi + 0= 130 psi –FLE= 70 psi 130psi + 70 psi= 200 psi
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Foam Production Foam must be proportioned with water and aerated with air to be used effectively Most fire fighting foams are designed to be mixed at 3% to 6% concentrate in water
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Foam & Foam Streams To be effective, foam concentrates must be matched to the fuel to which they are applied
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DETERMINE TYPE OF LIQUID POLAR SOLVENTS-.16 GPM SQ. FT. HYDROCARBONS -.10 GPM SQ. FT.
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HOW MUCH FOAM - NFPA 11 1.DETERMINE SQUARE FOOTAGE 10 FT. X 1OO FT.= 1000 SQ. FT. 2.DETERMINE TYPE OF LIQUID POLAR SOLVENT-.16 GPM/SQ. FT. HYDROCARBONS-.10 GPM/SQ.FT.
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APPLICATION RATES hydrocarbon fuels 3.DETERMINE AMOUNT OF FOAM CONCENTRATE. 100 GPM X.O3 = 3 Gal. Foam/Min. 4.AMOUNT REQUIRED FOR 15 MIN. 3 GPM X 15 MIN. = 45. Gal of Foam will be required.
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APPLICATION RATES hydrocarbon fuels 5.Determine amount of water needed 100 GPM X.97 = 97 GPM 97 X 15 = 1455 Gallons of Water
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Roll – On Method Bank Down Technique Rain – Down Method Foam Application Methods
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FOAM APPLICATION SCBA SWEEPING MOTION DO NOT PLUNGE FOAM DO NOT WALK IN LIQUID DO NOT TURN YOUR BACK TO FLAMMABLE DO PRESERVE THE FOAM BLANKET
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Causes of Poor Foam Generation Eductor and Nozzle Mismatch Too Much Hose between Eductor & Nozzle Nozzle Elevation Partially closed Nozzle Shut Off Kinked Discharge Line
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Fuel Mixture comprised of 85% ethanol and 15 % gasoline Fires should be treated differently than traditional gasoline fires- –These mixtures are polar/water-miscible flammable liquids ( ie- they mix readily with water) –Degrade effectiveness of fire-fighting foam which is not alcohol- resistant Refer to Guide 127 ( Flammable Liquids Polar/Water Miscible) of 2004 ERG
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PRACTICAL HOOK-UP EDUCTOR MAKE SURE NOZZLE MATCHES EDUCTOR SET METERING DEVICE SET FLOWING PRESSURE INSERT PICK-UP TUBE INTO FOAM
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QUESTIONS?
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DETERMINE AMOUNT OF FOAM CONCENTRATE 600 GPM X.03 = 18 GAL. FOAM MIN.
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Fluoroprotein Foam W Good water-retention capabilities W Excellent heat resistance W Not affected by freezing & thawing W Can be mixed with antifreeze W Good fluidity on fuel surface W Good water-retention capabilities W Excellent heat resistance W Not affected by freezing & thawing W Can be mixed with antifreeze W Good fluidity on fuel surface
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W Excellent water-retention capabilities W High heat resistance and re-ignition resistance W Performance can be affected by freezing and thawing W Can be mixed with antifreeze W Can be made resistant to alcohol Protein Foam Do not allow foam to plunge into burning liquids.
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