The systems for protecting flammable liquids use AFFF low expansion synthetic foam concentrates that act very rapidly by spreading over the surface of the burning liquid. Unlike traditional foams, aqueous film forming foams, in addition to forming a substantial layer of foam, generate by drainage an aqueous film that prevents the surface of the flammable liquid having contact with the air and stops the release of vapours. If the continuity of the film is broken, it has the ability to regenerate.
For applications on polar solvents, soluble in water, the alcohol-resistant foaming film AR-AFFF should be used. Once applied on polar solvents, the polymers (polysaccharides) present in the foam form a polymer film on the surface of the liquid. The polymeric film is generated by a reaction between the polar solvent and the water that drains from the foam. The aqueous film that floats on the polymeric layer maintains its ability to regenerate itself and contributes to extinguishing the fire and suppressing the vapours. Main use: flood or wet sprinkler systems for protecting flammable liquids.
AFFF and AR-AFFF foaming agents can be mixed with water in the proportion of 3% and 6% and are approved by the Ministry of the Interior. Medium and high expansion water and foam systems. The high expansion foam is used to extinguish fires of class A and B within confined spaces. The medium expansion foam, on the other hand, has been developed for applications in open windy locations. Both the high and medium expansion foam is aggregated with bubbles generated mechanically by passing the concentrated foaming agent through special generators and then subsequently coming into contact with the air. The expansion of the foaming agent can range from 20:1 up to 1000:1. The medium expansion systems can be used for the protection of combustible liquid and solid fuels where capillary coverage of the area to be protected is needed, for example for the total flooding of small spaces such as cabins with engines and transformers. They are used to protect flammable or toxic liquids where rapid flooding is vital to prevent the spread of vapours both for indoor and outdoor applications. High expansion foaming agent is used also for the protection of flammable liquids and provides greater capillary coverage for the areas to be protected. It is primarily suitable for the protection of different types of risk at various levels, for example inside palletised warehouses.