What class of fire does Aqueous Film-Forming Foam (AFFF) work best on?

Aqueous Film-Forming Foam (AFFF) is specifically designed to combat Class B fires, which involve flammable liquids, such as gasoline, oils, and paints. AFFF functions by creating a thin film over the surface of the burning liquid, effectively smothering the fire and preventing the release of flammable vapors. This film is crucial as it displaces air and cuts off the fire's access to oxygen, thereby extinguishing the flames.

In addition to its primary utility in Class B fires, AFFF also has some effectiveness with other fire classes, but it is primarily formulated for scenarios involving flammable liquids. Understanding the characteristics of each class of fire is vital for effective firefighting and response strategies. Class A fires involve ordinary combustible materials, Class C fires pertain to electrical equipment, and Class K fires are related to cooking oils and fats, which require specialized extinguishing agents. Thus, AFFF is most appropriately used for Class B fires where its unique properties can be utilized most effectively.