Which of the following is a common feature of AFFF?

Aqueous Film-Forming Foam (AFFF) is designed to combat flammable liquid fires, particularly those involving hydrocarbons like gasoline or oil. One of the primary characteristics of AFFF is its ability to form a film on the surface of flammable liquids. This film serves multiple purposes: it not only smothers the flames by cutting off the oxygen supply but also prevents the release of flammable vapors from the liquid surface, thus helping to suppress the risk of re-ignition.

The effectiveness of this film is essential for controlling fires, making AFFF a preferred choice in firefighting operations involving liquid materials. The formation of this vapor-suppressing film is a critical feature that distinguishes AFFF from other firefighting agents, as it enhances the foam's ability to suppress flames and protect the surrounding environment from fire spread.

This quality underlines the importance of understanding AFFF's unique properties and its application in various firefighting scenarios.