What is the best choice for extinguishing Class "B" fires?

The most effective extinguishing agent for Class "B" fires, which involve flammable liquids such as gasoline, oil, and solvents, is foam. Foam works by creating a blanket over the burning liquid, cutting off the oxygen supply and preventing vapor release, which can ignite and produce additional fire. This smothering action is vital in combatting fires that involve fuels that can float on water, as using water could spread the fire rather than suppress it.

Foam is particularly advantageous because it can also cool the fire and surrounding surfaces, reducing the likelihood of re-ignition after the flames are extinguished. The ability of foam to adhere to liquid surfaces further enhances its effectiveness, making it the preferred choice in firefighting for Class "B" incidents.

Other agents, while capable of extinguishing Class "B" fires, may not be as effective or suitable in every situation. For instance, dry powder agents are versatile but might not provide the same level of surface coverage as foam. Carbon dioxide is effective in displacing oxygen but may not adequately address the flammable vapors associated with Class "B" fuels.