These cylindrical units typically weigh 10-40 lb, are 20-30 in. high, have a discharge range of 30-50 ft, and discharge for 12-30 seconds. Each should be mounted conspicuously near eye level along fire exit routes, should be removable and usable by an inexperienced female operator, and should not weigh more 20 lb unless intended to be used by firefighters. Their contents are classed as described below:
A Contains water-based agents for use on wood, paper, and textile fires. Numerals before the letter indicate extinguishing potential: e.g. 40A will extinguish 20 times as much as 2A.
B Contains smothering or flame-interrupting chemicals for use on flammable liquids. Numerals before the letter indicate the area of liquid fire that an untrained operator can be expected to extinguish: e.g. 40B will extinguish about 40 sf of deep-liquid fire.
C Contains electrically nonconducting chemicals for use on fires on or near electric motors, switches, appliances, computers, and telecommunication equipment. Will operate at -40° F.
ABC Contains primarily ammonium phosphate for use on ordinary combustibles, flammable oils, and electrical wiring. N2G for electrical fires because it leaves a harmful residue.
D Contains dry chemical powders designed for use on specific combustible metals as listed on the extinguisher's nameplate.
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