What type of foam is commonly used to extinguish oil fires?

Aqueous Film Forming Foam (AFFF) is specifically designed for fighting fires involving flammable liquids, such as oils. AFFF works by creating a film that spreads across the surface of the burning liquid, effectively smothering the fire and preventing oxygen from reaching the flammable materials. This ability to create a barrier is crucial in extinguishing oil fires, as oils tend to float on water and can reignite if not properly covered.

Additionally, AFFF has a unique formulation that allows it to quickly suppress volatile vapors, further enhancing its effectiveness in controlling and extinguishing fires. This foam is widely used in both maritime and aviation applications, making it a standard choice for naval firefighting operations.

In contrast, some alternatives like alcohol-resistant foam are specific to alcohol fuels and may not provide the same level of efficiency for petroleum-based fires. Water mist is generally used for different types of fires and lacks the necessary film-forming capabilities required for oil fires. Dry chemical foams can extinguish a variety of fires but do not provide the same vapor suppression and film-forming advantages that AFFF does when dealing with flammable liquids like oil.