The classification of fire helps in selecting the appropriate extinguishing media according to the nature of the material undergoing combustion. The four classes of fire are given below.

Class A

Fires in ordinary combustible materials such as wood, cloth, paper, rubber and many plastics are classified under this. In general fires involving solid materials, usually of an organic nature, in which combustion normally takes place with the formation of glowing embers.

Water is the best extinguishing medium for Class A fires. Some Dry Chemical Powder (DCP) are also used.

Class B

Include fires involving liquids or liquefiable solids. Fires in flammable liquids, oils, greases, tars, oil based paints, lacquers, etc.

Foam is the best extinguishing medium for Class B fires. But its reactivity should be ensured in case of Chemical fires.

Class C

Fires involving gases. Flammable gases such as methane, natural gas, acetylene, etc.

Dry Chemical Powder is widely used for extinguishing gaseous fires. Its ability to cut the chain reaction in the combustion process makes it suitable for the purpose.

Class D

Fires involving metals, including magnesium, zirconium, sodium, lithium, potassium, etc.

Steam, Dry Chemical Powder can be used against meal fires.

The classification of fire tells us which fire extinguisher to be used for efficient extinction of fire.