TB 11 Pressurized Dry Chem Extinguisher Flashcards
The chemical itself is…
baking soda (sodium bicarbonate, NaHCO 2 )
It is treated to make it resistant to___ and ____.
Caking & Moisture
HOW IT WORKS:
Dry Chemical, in the presence of heat, releases ________and _______vapor which provides a “smothering action”
Carbon dioxide & Water vapor
HOW IT WORKS:
Heat is absorbed by both the solid particles and water vapor which provides ______
Cooling
Dry chemical is most effective on fires involving
flammable liquids
Flammable gases
liquefied gases.
Dry Chem is the fastest and most spectacular extinguishing material for …
Spilled fuel areas
Dry chemical is approximately ____as effective as CO2 on hydrocarbon fires, including______.
Twice, Methane
Dry Chem car fire technique should not be used unless at least ______firemen are presen
Two; 1 for rescue and 1 to provide protective cover.
When an acid spill is encountered, pull the locking pin, hold the nozzle ___or ___feet above the acid, squeeze the valve just enough to allow the powder to flow gently from the nozzle and spread the powder over the surface of the acid.
2 or 3 ft
When fires are encountered involving leaks of gases, especially those “heavier than air“ such as ________ & _______the fire ordinarily should not be extinguished until control of the gas can be obtained,
Butane & Propane
dry chemical, such as is used in LAFD portable extinguishers, causes ____________of “foam blankets”when used in conjunction with ________ foam.
rapid breakdown and collapse
Mechanical Foam
Dry Chem is ineffective on metal fires such as __________and _________
Magnesium & Sodium
Because of its dielectric characteristics, dry powder can be used safely’ on ?
Electrical Fires
Shell tank of Dry Chem extinguishers are tested to _____ psi
600
The nozzle of extinguishers shape the dry chem into a __ degree fan stream
60
The shell is filled with twenty ___pounds of dry chemical and then pressurized to approximately _____ psi with compressed air.
20 lbs
165 psi
This extinguisher has a rating of _______
meaning that in the hands of an average operator it is capable of extinguishing a ____square foot deep-layer Class B fire, and is safe for use on fires involving energized electrical equipment.
20-B,C rating
20 sq ft
discharge time of a 20- pound dry chemical extinguisher with the valve fully open is…
10 seconds
The 20 pound CO 2 extinguisher in use on the Department will last…
60 seconds
Dry Chem extinguisher has an effective range of approximately…
15 to 20 feet
To prevent splashing when using on depths of flammable liquid, care should be taken to direct the initial discharge from a distance not closer than…
6 to 8 feet
Dry Chem should be checked ____ should be checked…
DAILY
Dry chems full charge is b/w ____-_____
125-175psi
___________ remove the extinguisher from the rack, invert it, and shake to preclude any possibility of the chemical caking.
Once each Month
