What type of fire extinguisher is suitable for a Class B fire?

Foam and CO2 extinguishers are specifically designed to combat Class B fires, which involve flammable liquids such as gasoline, oil, and solvents. The foam works by forming a blanket over the flammable liquid, effectively smothering the fire and preventing vapors from igniting. CO2 extinguishers are effective as well because they can displace oxygen in the vicinity of the fire and cool the burning fuel; they are particularly useful for fires where a clean extinguishing method is needed, such as in enclosed spaces or near electrical equipment.

Class B fires require extinguishing agents that do not conduct electricity and that can effectively cut off the oxygen supply or cool the burning material. Foam and CO2 are both effective in achieving these results, making them ideal for this type of fire.

Other types of extinguishers mentioned, like water extinguishers, would be ineffective, as water can spread flammable liquids or cause hazardous reactions. Dry powder extinguishers can also be suitable for Class B fires, but the specific call-out of foam and CO2 denotes their prime effectiveness in situations where flammable liquids are involved. Wet chemical extinguishers are primarily used for Class K fires, typically involving cooking oils and fats, rather than Class B fires