What type of extinguishing agent is typically used to extinguish a Class B fire?

When dealing with a Class B fire, which involves flammable liquids such as gasoline, oil, and other petroleum products, it is crucial to use an extinguishing agent that can effectively handle such materials. Carbon dioxide is a common extinguishing agent for Class B fires because it displaces oxygen in the area of the fire, which helps to suffocate the flames. Additionally, carbon dioxide does not leave a residue and is safe to use on fires involving electrical equipment, making it versatile.

Foam is also effective for Class B fires and can create a barrier between the fuel and the oxygen, preventing re-ignition. Dry powder agents are effective as well, especially those designed for flammable liquids, but they tend to leave a residue that can be more cumbersome to clean up compared to carbon dioxide.

Water is not suitable for Class B fires, as it can cause flammable liquids to spread rather than extinguish the fire. Hence, carbon dioxide stands out as a preferred choice due to its immediate effectiveness and minimal clean-up requirements.