Water extinguishers are effective for which class of fires?

• A. Class A agent
• B. Class B agent
• C. Class C agent
• D. Class D agent

Answer: (A)

Water extinguishers are most effective on ordinary combustibles such as wood, paper, and textiles. They work by absorbing a lot of heat, cooling the fuel so it drops below its ignition temperature and the flame can no longer sustain combustion. This cooling action directly interrupts the burning process for these fuels.

They aren’t suitable for other fire types. For flammable liquids, water can spread the liquid and push the fire to new areas, making things worse. For electrical fires, water conducts electricity, creating shock hazards and the risk of energizing exposed equipment. For metal fires, many metals react with water, potentially causing dangerous reactions or explosions; these fires require special extinguishing agents.