Fire Extinguisher Class A is used for fires involving which materials?

• A. Metals
• B. Electrical equipment
• C. Ordinary combustibles such as wood, paper, cloth
• D. Flammable liquids such as gasoline, oil

Answer: (C)

Fires are matched to extinguishing methods based on the type of fuel. Class A extinguishers are designed for ordinary combustibles that leave ash, such as wood, paper, and cloth. They work mainly by cooling the fuel, absorbing heat so the temperature drops below the fuel’s ignition point and the flame can no longer be sustained. That cooling action makes them the most effective choice for those materials.

Fires involving metals require a Class D extinguisher with a special powder to prevent the metal from reacting and to smother the fire; electrical fires need a non-conductive agent and often the circuit must be de-energized first; flammable liquids like gasoline or oil need a Class B extinguisher that blocks vapors and air rather than cooling with water, which can spread the liquid or worsen the fire. So for ordinary combustibles such as wood, paper, and cloth, a Class A extinguisher is the appropriate option.