Which class of extinguisher is typically used for ordinary combustibles like wood and paper?

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

Answer: (C)

Fires involving ordinary solid fuels like wood and paper are best fought by extinguishers that focus on cooling the fuel. That’s what extinguishers designed for solid combustibles do: they use water or other cooling agents to absorb heat, dropping the temperature of the material below its ignition point and stopping the flame from continuing. Once the fuel is cooled, the fire goes out.

Other extinguisher types handle different hazards—flammable liquids, electrical fires, or reactive metals—so they aren’t the right fit for ordinary combustibles. So for wood, paper, and similar materials, the extinguisher intended for solid, ordinary combustibles is the best choice.