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
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.