Class B fires involve:

• A. Energized electrical equipment.
• B. Combustible metals.
• C. Ordinary combustibles.
• D. Flammable liquids.

Answer: (D)

Class B fires involve flammable liquids. These fires are started by liquids like gasoline, oils, solvents, and other hydrocarbons that produce vapors which can ignite and spread rapidly across a surface. Because the fuel is a liquid, water usually isn’t the best choice—it can spread the liquid and worsen the fire. Instead, extinguishing agents that blanket or isolate the fuel, such as foam, dry chemical powders, or specialized CO2/ABC combinations, are used to cool and separate the fuel from the air.

Energized electrical equipment fires fall into another category, ordinary combustibles (like wood and paper) into a different one, and combustible metals into yet another, so recognizing the fuel type helps determine the right suppression approach.