Water is primarily used on which class of fire?

Water is primarily used on Class A fires, which involve ordinary combustible materials such as wood, cloth, paper, rubber, and certain plastics. The effectiveness of water in extinguishing these fires lies in its ability to cool the burning material and reduce the temperature below the ignition point. Water also helps to create steam, which can displace oxygen and further assist in extinguishing the flames.

Using water is inappropriate and potentially dangerous for Class B fires (flammable liquids), Class C fires (electrical equipment), and Class D fires (combustible metals), as water can spread flammable liquids, conduct electricity, or exacerbate the fire in the case of metals. Therefore, understanding the proper application of water is crucial in firefighting efforts focused specifically on Class A fires.