AFFF foam solutions are rated for application concentrations of which range?

• A. 1% to 3%
• B. 6% to 9%
• C. 3% to 6%
• D. 0.5% to 1%

Answer: (C)

AFFF foam performance depends on using the concentrate at the right dilution with water. The finished foam solution needs a certain amount of concentrate to form the film on hydrocarbon fuels and to create a stable foam blanket that both suppresses vapors and cools the fuel.

The common rated application range for many AFFF products is 3% to 6%. At about 3%, the solution reliably forms the protective film and provides effective vapor suppression. Increasing to around 6% enhances the film and cooling for tougher fires or larger spills. Using much less than 3% often fails to produce a consistent film, while using more than 6% isn’t typically necessary for standard AFFF products and can waste concentrate or introduce other operational issues. So, the recommended and typical application concentrations fall in the 3% to 6% range.