What does AFFF stand for and what is its primary firefighting function?

• A. Aqueous Film Forming Foam; it creates a persistent film that cools, suppresses vapors, and prevents fuel-to-air contact to control hydrocarbon fires.
• B. Alcohol-based Foam; it coats surfaces but does not form a film to block vapors.
• C. AFFF stands for All-purpose Fire Fighting Fluid with rapid cooling properties.
• D. Foam concentrate used only for aqueous systems without forming a film.

Answer: (A)

Aqueous Film Forming Foam, and its main firefighting action is to form a thin, persistent film on the surface of hydrocarbon fuels. This film creates a barrier between fuel and air, helps cool the fuel surface, and suppresses vapors, all of which slow or stop the fire and aid extinguishment. The other options misstate either the acronym or the film-forming capability, whereas the defining feature of AFFF is this rapid film formation that blocks fuel-to-air contact while providing cooling.