AFFF stands for Aqueous Film Forming Foam, which is a type of firefighting foam widely used to suppress and extinguish flammable liquid fires, such as those involving gasoline, oil, and other petroleum-based products. AFFF is designed to create a thick blanket of foam that covers the fuel's surface, preventing the release of flammable vapours and cooling down the fire. This foam also helps to separate the fire from the surrounding oxygen, thus interrupting the combustion process.

 

AFFF contains a mixture of water, foam concentrate, and air-entraining agents. The foam concentrate contains fluorinated surfactants that lower the surface tension of water and help it to spread evenly across the fuel's surface, forming a thin and stable layer. This layer acts as a barrier, suppressing both the fire's heat and its access to oxygen. AFFF is purchased as a concentrate, typically referred to as “3%” or “6%” (Type 3 or Type 6, respectively) depending on its mixture ratio with water.

 

AFFF is commonly used in firefighting situations involving flammable liquid spills, industrial fires, and scenarios where traditional water-based firefighting methods are less effective. It is deployed using specialized firefighting equipment, such as foam generators and nozzles, to ensure effective coverage of the fuel's surface.