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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.)
OBJECTIVES
• TERMS
• HOW FOAM WORKS
• FOAM GENERATION
• TYPES OF FOAM
• APPLICATION RATES
• FOAM EQUIPMENT
• PRACTICAL EVOLUTION
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
Smothering: prevents release of vapors
Foam’s Extinguishing Characteristics
Separating: creates a barrier between the fuel and fire
Cooling: lowers temperature of the fuel
Limitations of Foam
• Foam solution is 94%-97% water– Cannot be used on:
• Electrical fires• Three Dimensional Fires• Pressurized Gases• Combustible Metals
Kinds of Foam
• Protein
• Fluroprotein
• Film Forming Protein (FFFP)
• Aqueous Film Forming Foam (AFFF)
• Alcohol Resistant AFFF (ARFFF)
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
Foam Delivery Systems
• In-Line Eductors
• Around the Pump Eductor
• Compressed Air Foam System
• By-Pass Line Eductor
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
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.
HYDRAULICS
Back Pressure should not exceed 70% of inlet pressure
• Back Pressure=NP+FLH+FLE250’ of 1.75” and 0’ elevation – FLH= 100 + 30psi + 0= 130 psi– FLE= 70 psi
• 130psi + 70 psi= 200 psi
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
Foam & Foam StreamsFoam & Foam Streams
To be effective, foam concentrates must be matched to the fuel to which they are applied
HOW MUCH FOAM - NFPA 11
1. DETERMINE SQUARE FOOTAGE
10 FT. X 1OO FT.= 1000 SQ. FT.
2. DETERMINE TYPE OF LIQUIDPOLAR SOLVENT- .16 GPM/SQ. FT.
HYDROCARBONS- .10 GPM/SQ.FT.
APPLICATION RATEShydrocarbon 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.
APPLICATION RATEShydrocarbon fuels
5. Determine amount of water needed100 GPM X .97 = 97 GPM
97 X 15 = 1455 Gallons of Water
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
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
• 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
PRACTICALPRACTICAL
• HOOK-UP EDUCTOR
• MAKE SURE NOZZLE MATCHES EDUCTOR
• SET METERING DEVICE
• SET FLOWING PRESSURE
• INSERT PICK-UP TUBE INTO FOAM
Fluoroprotein FoamFluoroprotein Foam
Good water-retention capabilities
Excellent heat resistance
Not affected by freezing & thawing
Can be mixed with antifreeze
Good fluidity on fuel surface
Good water-retention capabilities
Excellent heat resistance
Not affected by freezing & thawing
Can be mixed with antifreeze
Good fluidity on fuel surface
Excellent water-retention capabilitiesHigh heat resistance and re-ignition resistancePerformance can be affected by freezing
and thawingCan be mixed with antifreeze Can be made resistant to alcohol
Excellent water-retention capabilitiesHigh heat resistance and re-ignition resistancePerformance can be affected by freezing
and thawingCan be mixed with antifreeze Can be made resistant to alcohol
Protein FoamProtein Foam
Do not allow foam to plunge into burning liquids.
Do not allow foam to plunge into burning liquids.