Various types of Fire Extinguisher are of value but all are not equally effective as all types of fire. For all practical purpose, the basic types of fires can be grouped into following classes of fires:

Class A Fire
Fires involving solid combustible materials of organic nature such as wood, paper, rubber, plastics, etc.,where the cooling effect of water is essential for extinction of fires.

Class B Fire
Fires involving flammable liquids or liquefiable solids or the like where a blanketing effect is essential.

Class C Fire
Fires involving flammable gases under pressure including liquified gases, where it is necessary to inhibit the burning gas at fast rate with an inert gas, powder or vaporizing liquid for extinguishment.

Class D fires
Fires involving combustible metals, such as magnesium, aluminium,zinc,sodium, potassium,etc., when the burning metals are reactive water and water containing agents and in certain cases carbon dioxide, halogenated hydrocarbons and ordinary dry powders. These fires require special media and techniques to extinguish.

Class Electric Fires
Where energised electrical equipment is involved in a fire, non-conductivity of the extinguishing media is of utmost importance, and only extinguishers expelling dry powder, carbon dioxide (without metal horn) or vaporizing liquids should be used.Once the electrical equipment is de-energized,extinguishers suitable for the class of fire involved can be used safely.