Fires fueled by flammable liquids or gases are Class B fires. The primary extinguishing agent for this class is ______.

Fires fueled by flammable liquids or gases are Class B fires. The primary extinguishing agent for this class is ______.

• A. FOAM
• B. WATER
• C. DRY CHEMICAL
• D. CO2

Answer: (A)

Fires involving flammable liquids are best suppressed by an agent that both cools the fuel and blankets the liquid surface to block the flame from the fuel and air. Foam accomplishes this by spreading over the liquid, forming a stable layer that cools the fuel and separates it from the air, effectively starving the flame and preventing re-ignition. Water can spread the flammable liquid and isn’t reliable for this class of fire. Dry chemical is versatile but not the primary choice for Class B; CO2 displaces oxygen and doesn’t adequately blanket a liquid surface. Therefore, the primary extinguishing agent for Class B fires is foam.

Fires involving flammable liquids are best suppressed by an agent that both cools the fuel and blankets the liquid surface to block the flame from the fuel and air. Foam accomplishes this by spreading over the liquid, forming a stable layer that cools the fuel and separates it from the air, effectively starving the flame and preventing re-ignition. Water can spread the flammable liquid and isn’t reliable for this class of fire. Dry chemical is versatile but not the primary choice for Class B; CO2 displaces oxygen and doesn’t adequately blanket a liquid surface. Therefore, the primary extinguishing agent for Class B fires is foam.