Flammable liquids, oils, and solvents are classified as which class of fire?

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

Answer: (A)

Fire classifications group fires by the fuel involved. Flammable liquids, oils, and solvents are designated as Class B fires because the danger comes from the liquids’ vapors that can ignite and spread rapidly, often with the liquid itself floating on surfaces or releasing vapors that travel to the flame. This type of fire is treated with extinguishing agents that cool, blanket, or chemically interrupt the flame, such as foam, dry chemical powders, or CO2, and water is generally not the best choice because it can spread the liquid and worsen the fire.

This differs from other categories: ordinary combustibles like wood and paper are Class A; energized electrical equipment fires are Class C; and combustible metals like magnesium are Class D.