Which type of fire extinguisher is used for Class B fires?

Class B fires involve flammable liquids and gases, such as gasoline, oil, and solvents. The appropriate extinguishing agents for these types of fires are foam, carbon dioxide (CO2), or dry chemical extinguishers.

Foam extinguishers work by creating a barrier between the fuel and the oxygen, effectively smothering the fire. CO2 extinguishers displace the oxygen and cool the fuel, making them effective for liquid fires without leaving behind any residue. Dry chemical extinguishers, particularly those using sodium bicarbonate or monoammonium phosphate, work by interrupting the chemical reaction of the fire.

While other options may be used in certain scenarios, they are less suited for Class B fires. Water extinguishers can be dangerous because water can spread flammable liquids. ABC powder extinguishers are designed for all three classes (A, B, C), but the specific focus on effective agents for Class B aligns directly with foam, CO2, or dry chemical extinguishers. Wet chemical extinguishers are tailored mostly for cooking oil and grease fires, which are a specific subtype of Class K rather than Class B. Thus, the designated types that are optimally effective against Class B fires are those listed.