What type of foam is primarily used for flammable liquid fires?

Film-forming foam is specifically designed to combat flammable liquid fires, such as those involving hydrocarbons (e.g., gasoline, oils). This type of foam creates a film on the surface of the burning liquid, effectively smothering the flames and preventing the release of flammable vapors. The film also helps to cool the fire and shield the fuel surface from heat, reducing the chances of re-ignition.

In situations involving flammable liquids, it’s crucial to use a foam that can effectively deal with both the fire and the potential for re-ignition. Film-forming foam is particularly effective because it’s engineered to spread quickly across the burning liquid, forming a barrier that cuts off the oxygen supply and suppresses the fire more efficiently compared to other foam types.

Protein foam, on the other hand, is less effective against fast-spreading flammable liquids due to its slower application and lack of a film-forming capability. Alcohol-resistant foam can be used for polar solvents, but may not be ideal for all types of flammable liquids. Class A foam is primarily designed for combating ordinary combustibles like wood and paper, making it unsuitable for flammable liquid fires.