TB 011 - Pressurized Dry Chemical Fire Extinguishers Flashcards
The chemical itself is baking soda (sodium bicarbonate, ________ __) especially treated to make it resistant to caking and moisture, and capable of being readily dispersedinto a fire-killing cloud.
NaHCO 2
Dry Chemical, in the presence of heat, releases carbon _______ and _______ vapor which provides a smothering action.
Dioxide Water
Heat is absorbed by both the ______ particles and water vapor which provides cooling.
Solid
Dry chemical is effective on fires involving deep-layer __________ liquids, natural ____ leaks, and ___________ flammable gas leaks and spills.
Flammable Gas Liquefied
Dry chemical is approximately ______ as effective as CO2 on hydrocarbon fires, including ___________, for a given size extinguisher.
Twic Methane
This extinguisher is especially suitable for use on fires in grease ducts above stoves, when applied into the ______ end of the duct.
Lower
There has been an increasing use of dry chemical on Class A fires, especially in textile fibers such as ________.
Cotton
When a car fire involving occupants is encountered, there are certain advantages to using dry chemical; the powder can be used as a ______ screen to quickly move in on the fire and rescue the occupants, in addition, the powder will not have any adverse effect on the occupants of the car, where the use of ______ spray on the victim could result in steam burns and would not allow as quick access to the car.
Heat Water
If a reflash should occur and involve firemen or civilians, do not hesitate to engulf them in a cloud of ________.
Powder
The dry chemical in these extinguishers can also be used to neutralize ______ spills.
Acid
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 3
When fires are encountered involving leaks ofgases, especially those heavier than air (__________, ___________,etc.) the fire ordinarily should not be extinguished until control of the gas can be obtained
Butane Propane
A disadvantage of using dry chemical is its lack of _______ after extinguishment.
Control
Dry chemical is non-_______. Although some irritation of the _______ and nasal passages may be experienced, there should be no residual effect under normal conditions.
Toxic Throat
The normal precautions should be taken, however, when moving into confined areas since the _________ content may be below that necessary for breathing.
Oxygen
Because of its __________ characteristics, dry powder can be used safely’ on electrical fires, such as fires involving oil cooled electric switches and transformers.
Dielectric
Because of its slight __________ and abrasive properties, it should be used with care on fires in fine electrical or electronic gear, such as printing presses, I.B.M. equipment, telephone switchboards, etc. This consideration, however, should be _________ to thecontrol of the fire.
Corrosive Secondary
This extinguisher consists of: a. a shell of heavy gauge steel, tested to ____ psi
600
This extinguisher consists of: a ______ reinforced hose
Nylon
This extinguisher consists of: a _________ control squeeze grip valve.
Positive
This extinguisher consists of: a nozzle which shapes the dry chemical into a ___ degree fan stream
60
This extinguisher consists of: an air pressure gauge protected by a ________ guard.
Gauge
The shell is filled with ___ pounds of dry chemical and then pressurized to approximately _____ psi with compressed air.
20 165
This extinguisher has a rating of ___-B,C, 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 _________ electrical equipment.
20 20 Energized
An ________ operator will be able to extinguish an even larger “fire with this extinguisher.
Expert
keep extinguisher _______ while in use
Upright
The discharge time of a 20- pound dry chemical extinguisher with the valve fully open is ___ seconds.
10
The 20 pound CO 2 extinguisher in use on the Department will last ___ seconds.
60
When using the extinguisher on a fire, the valve normally should be ______ ______ to maintain proper discharge and to preclude any possibility of the valve becoming clogged.
Wide Open
Best results are obtained with this type extinguisher by working from ___________ side of fire and floating powder in over the fire.
Windward
With a ______-to-_____ sweeping action, cover the entire area of fire.
Side Side
The extinguisher has an effective range of approximately ___ to ___ feet.
15 20
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 __ to ___ feet.
6 8
The pressure gauge should be checked ______ for a full charge.
Daily
The extinguisher will function effectively only so long as the air pressure is between ____ to ____ psi.
125 175
MAINTENANCE; Inspect
____________ and after use to detect deteriorate worn, or damaged parts.
Periodically
MAINTENANCE; Inspect nozzle periodically for any obstruction or collection of _________.
Moisture
MAINTENANCE; Once each _______ , remove the extinguisher from the rack, invert it, and shake to preclude any possibility of the chemical caking.
Month
RECHARGING; Tag the extinguisher with a F-175 tag and send it to the shops, whenever it needs to be recharged with ____ or dry chemical.
Air
