Class B fires involve which material?

• A. Electrical equipment
• B. Ordinary combustibles
• C. Flammable liquids
• D. Metals

Answer: (C)

Class B fires involve fuel in liquid form—that is, flammable liquids. This category covers liquids capable of producing ignitable vapors, such as gasoline, kerosene, solvents, oils, and many fuels used in industry. These fires behave differently from solid combustibles, and from electrical equipment fires, because the liquid fuel can spread and pool, creating a larger fire surface and continuous ignition risk. That’s why Class B fires are identified by the involvement of flammable liquids, rather than solids or energized equipment. Extinguishing approaches focus on preventing vapor ignition and separating the fuel from heat, using agents like foam, dry chemical powders, or CO2, rather than relying on methods suited for solid materials or electrical fires.