Which material category describes Class A fire?

• A. Ordinary combustible materials
• B. Flammable liquids
• C. Energized electrical equipment
• D. Metals

Answer: (A)

Class A fires involve ordinary combustibles—things like wood, paper, cloth, and many plastics—that burn with heat and typically leave ash as they oxidize. This is why ordinary combustible materials is the correct description for Class A fires: the defining factor is the type of fuel. Flammable liquids describe Class B fires, energized electrical equipment describes Class C fires, and metals describe Class D fires, so they don’t fit Class A. In terms of suppression, these fires are addressed by cooling the fuel below its ignition temperature to stop the burning process, which aligns with how ordinary combustibles respond to extinguishing methods.