Which extinguisher designation is appropriate for fires involving flammable liquids?

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

Answer: (D)

Fires involving flammable liquids require extinguishing methods that prevent the fuel from feeding the flame. Class B extinguishers are designed for this scenario. They work by smothering the liquid or disrupting the chemical reactions at the flame, using agents such as dry chemical powders, foam, or CO2. Water-based extinguishers would spread a flammable liquid and make the fire worse, so they’re not appropriate for these fires. Fires involving ordinary combustibles like wood or paper fall under Class A and are addressed by cooling with water or foam, electrical fires fall under Class C and require nonconductive agents, and metal fires are Class D, needing specialized powders. Therefore, the appropriate designation for fires involving flammable liquids is Class B.