Effect of Fluorosurfactant on Foam Stability, Sealability and Fire Performance of Firefighting Foam Under Heptane Fuel

ABSTRACT To investigate the influence of fluorosurfactant on stability, sealability and fire performance of aqueous film‐forming foam (AFFF), formulations composed of fluorosurfactant, alkyl polyglycoside, ethylene glycol butyl ether, glycerol and diluted were prepared. Among these components, the content of fluorosurfactant was adjusted to obtain formulations capable or incapable of forming an aqueous film on heptane. Results of microstructure test showed that the drainage time was positively correlated with the fluorosurfactant content. However, the presence of fuel significantly shortened the drainage time, and a more pronounced destabilizing effect was observed in formulations with lower fluorosurfactant content. A gap within the foam column was observed exclusively in the presence of fuel, and its height increased progressively as the fluorosurfactant content decreased. The formulations capable of forming the aqueous film showed similar sealability performance for heptane, whereas it improved gradually with increasing fluorosurfactant content for those unable to form the film, making a trend consistent with the observed changes in foam stability. Our results revealed that the fire performance was consistent with the foam stability in this work, particularly the foam stability in the presence of fuel, which can be used as preliminary evaluation indicators during formula development.