Aqueous film forming foam (AFFF) is a variation of foam fire extinguishers made specifically to combat Class A fires (plastic, wood, textiles and other solid combustible materials) and types of Class B fires (diesel, petrol and paint).
AFFF works by creating a foam barrier that smothers the oxygen needed to generate a fire, which also stops the fire from re-igniting. However, after decades of use, the AFFF type is phased out in the UK as of 4th July 2025.
While the AFFF has been utilised for many years, the man-made chemicals used for the barrier and smothering technique of the foam, perfluoroalkyl and polyfluoroalkyl substances (PFAS), are known as ‘forever chemicals’ as they do not break down as easily as other chemicals and thus raise a significant health risk to health and environmental concerns.