What is the term for foam that creates a barrier to suppress flames effectively?

The term that refers to foam creating a barrier to effectively suppress flames is film-forming foam. This type of foam works by forming a thin film over the fuel surface, which not only prevents oxygen from reaching the flames but also inhibits the release of flammable vapors. This barrier is crucial in suppressing fires, especially those involving flammable liquids.

Film-forming foam is particularly effective in dealing with hydrocarbon fires, as it can quickly spread over the liquid surface, forming a protective layer that enhances fire suppression. It's designed to be used in a variety of environments, including airports, where the rapid containment of fuel spills is essential for safety.

Different types of foam may have specific applications, such as AFFF (Aqueous Film-Forming Foam), which is a subtype of film-forming foam that is used for both polar and non-polar fuels. However, the term "film-forming foam" more broadly encompasses foams designed to create this flame-suppressing barrier, distinguishing it from other types like protein-based or water-soluble foams that may not have the same efficacy in establishing a barrier against flames.