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Classification of Fires & Size of Extinguisher
Classes of Fire
fires involve ordinary combustibles such as wood, paper, rubber,
cloth, most plastics, etc. Almost everything in your home is
considered a Class A combustible.
fires involve combustible and flammable liquids and gases, such as
gasoline, kerosene, grease, tar, acetone, fingernail polish, some household
cleaning products, etc. Some plastics are considered Class B because they melt
first, then burn just like a flammable liquid.
||Class C fires involve anything with energized electricity. Once the electrical
power is taken away, the fire goes back to being a Class A or B fire.
||Some extinguishers are multi-purpose
which means they can be used for more than one class of fire. The
extinguishers provided in most buildings are classified for A, B, and C fires.
What size is my extinguisher?
Extinguishers are also rated according to the amount of fire that can be extinguished
by an untrained layperson. The minimum rating for most occupancies is 2-A:10-B:C. The
2-A means the extinguisher will extinguish as much fire as a 2-1/2 gallon water extinguisher
on ordinary combustibles (about as much as a trash can would hold). The 10-B relates to the
amount of fire involving flammable liquids, usually ten square feet. The C means the
extinguisher's agent is non-conductive. The rating is found where the Underwriters
Laboratory© mark is located, usually on the back or side label, along with the type of
extinguisher (i.e., Dry Chemical Fire Extinguisher).