Which statement best describes Class B fires?

• A. They involve flammable liquids.
• B. They involve solids.
• C. They involve electrical equipment.
• D. They involve gases.

Answer: (A)

Fires that involve flammable liquids are classified as Class B. The defining feature is that the fuel is a liquid, such as petrol, diesel, solvents, or other hydrocarbon liquids, which can form a flammable vapour that ignites when mixed with air. Because of this fuel type, extinguishing approaches focus on cooling and smothering the liquid or separating the vapour from the air—foam blankets, dry chemical powders, or CO2 are typical choices. Water is usually avoided for liquid fires because it can spread the flammable liquid and spread the fire.

In contrast, fires caused by solids (like wood or paper) fall under Class A, and those involving electrical equipment or gases fall under different classifications. That’s why the statement describing Class B fires as involving flammable liquids is the best fit.