Gasoline, oil, and organic solvents belong to which fire class?

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

Answer: (B)

Fires are categorized by the type of fuel involved, because different fuels burn in different ways and require different extinguishing approaches. Gasoline, oil, and organic solvents are flammable liquids with low flash points; their vapors readily form ignitable mixtures with air. When these liquids burn, the hazard comes from the liquid’s vapors rather than a solid material or an electrical source. That makes them a Class B fire. Class A covers ordinary combustibles like wood or paper, Class C includes energized electrical equipment, and Class D involves certain reactive metals. For liquid fires, water is generally not the best choice and extinguishing media such as foam, dry chemical, or CO2 are used.