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

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

Answer: (C)

Fires involving ordinary combustibles such as wood or paper are Class A. These materials are solid fuels that burn by oxidation and typically form ash as they leave residue. The key to extinguishing them is removing heat, which stops the fuel from staying above its ignition temperature, so water-based extinguishers are effective because they cool the material and halt the burning process. Other fire classes cover different fuels: Class B covers flammable liquids, Class C covers energized electrical equipment, and Class D covers combustible metals, each requiring different suppression methods tailored to the fuel and conditions.