Which class of fire involves ordinary combustibles such as wood and paper?

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

Answer: (A)

Fires involving ordinary combustibles such as wood and paper are Class A. These materials burn primarily due to heat that must be removed to stop the fire; cooling with water is especially effective because it absorbs a large amount of heat and drops the material below its ignition temperature. The hallmark of these fires is that they typically leave ash, reflecting the non-metal, non-liquid nature of the fuel. In contrast, other classes cover different fuels: flammable liquids for Class B, energized electrical equipment for Class C, and certain reactive or combustible metals for Class D. So the scenario described matches Class A.