1% AFFF Can you make a better aqueous film forming than Denko 3% Concentrate? Not really, but you can make it more cost effective. Tripling the concentration yields a finished foam solution that will cost over 20% less. This also means tripling the amount of fire fighting capability that can be carried to the fire scene a third the amount of space necessary for storage. In addition Denko 1% AFFF is freeze protected and it too has an indefinite shelf-life.