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18 Cards in this Set
- Front
- Back
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How does foam extinguish a fire? |
Diluting- surrounding air with water vapour creates as it evaporates Isolating- fuel from oxygen in the air Forming- sealing blanket over surface of flammable material preventing vapour escaping Intercepting- radiant heat from flames preventing it reaching the surface of fuel and causing further evaporation Cooling- the fuel |
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Classifications of foam? |
Low expansion- ratio from 2:1 to 20:1 Medium expansion- from 20:1 to 200:1 (not used by LFB) High expansion- 200:1 to 2000:1 |
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What is low expansion foam (LX) made from and what are the 3% and 3% mixtures with water used for? |
ARFFFP- alcohol resistant film forming fluroprotein Auxquimia- changes as this one has lower environmental impact 3%- fires involving hydrocarbons (doesn’t mix with water e.g petrol/oil) 3%- fires involving polar solvents (liquids which are water miscible- dissolve in water) |
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Three factors that can be varied with foam? |
Volume of air mixed with volume of solution The size of the bubbles (medium and high expansion concert rates only) Quantity of foam concentrate added
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The effectiveness of foam depends on what factors? |
Concentrate in good condition Correct mixture of concentrate used Good maintenance of equipment Correct pump pressure used for the equipment |
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Method of application for low expansion foam? |
Gentle application Rain down Rolling on Off wall- indirect application |
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Mercury ground monitor with foam nozzle details? |
Must have foam aspirator nozzle screwed in and fixed to 950lpm at 7 bar and a throw of 55m The jet must be directed away from the fire until a good foam mixture is produced |
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Considerations when applying foam? |
Never apply water onto burning liquid Always open branch away from fire until consistent supply of foam If burning liquid flowing, apply foam to the furthest point from fire first Make sure there is enough foam to apply and maintain a foam blanket Any surrounding risks should be cooled with covering jets while necessary resources are obtained (foam can be used to control fire spread if available) Once application completed foam blanket must be preserved until liquid is cooled, don’t use water this can break down foam Take care to not walk on or drag hose through foam as can disturb blanket allowing re-ignition |
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What is used for high expansion foam? |
Angus Turbex Mark 2 Comes with 30m foam discharge polythene tubing which is used to deliver hi-ex foam to basements and ships holds |
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High expansion foam hazards? |
Claustrophobia Disorientation Severely affected light penetration Limited audibility Mini backdraughts and fire has explosions due to trapped pockets of oxygen starved fire and un-ignited fire gases Difficulties in determining the travel and location of fire because of reduction in transmission of heat meaning FF’s can get very near fire without realising Difficulty in spotting surrounding damage/signs of damage as may be obscured |
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Bulk foam unit (BFU’s) specs and where are they kept? |
Barking, Harrow and Kingston each crewed by one FF driver/fork lift driver BFU is a flatbed lorry with forklift loaded intermediate bulk containers (IBC) and equipment stillages (stowage containers) Stowage is as follows: 8 x 1000 L IBC of low ex foam 1 x 1000 L IBC of high ex foam 2 x equipment stillages containing: 1 x turbex hi ex foam gen, 2 x foam monitors + ancillary equipment and all equipment necessary for connecting IBC’s to foam producing equipment |
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Delta attack with foam aspirator specs? |
Branch flow must be set to 400lpm with nozzle set to jet Foam can be projected up to 23m Will use approx 15L foam compound per min Branch operator must inform pump operator before they close the branch, so pump operator can close RPI first
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Considerations when using LX foam? |
Visor down Jet away from fire until foam is flowing Apply gently to surface of burning fuel Do not plunge jet into burning liquid |
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What does RTP and RTPP stand for? |
Round the pump Round the pump proportioner |
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How much foam can the fire engine have and what are other ways to use foam? |
Foam tank- 80 litres Foam transfer in- from IBC or external foam source |
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When using foam with the RB101 what settings should be used? And ground monitor? |
6 bar at 400lpm 7 bar at 950lpm |
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Advantages of using foam inlet? |
Can be used without FF having to enter fire compartment Inlet is usually a tapered orifice auditable for most branches Protected by glass panel marked foam inlet which indicates level of risk involved |
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Lost of procedures to get foam working? |
Engage pto, close hose reels and set pump to low pressure Set tank to pump and auto fill switches to open Set the chosen switch (tank to pump transfer in or out) to open Adjust the proportioned to required number of branches or monitors and open the appropriate branches Increase pump speed to deliver requested pressure from branch to monitor |
