Extinction Performance Summary of Commercial Fluorine-free Firefighting Foams over a 28 ft2 Pool Fire Detailed by MIL-PRF-24385
Technical Report,01 Oct 2019,01 Nov 2019
NAVAL RESEARCH LAB WASHINGTON DC WASHINGTON United States
Pagination or Media Count:
Commercial fluorine-free firefighting foams were evaluated at conditions relevant to military qualification testing. Extinction and burnback times were quantified over a 28 ft2 pool fire using heptane and gasoline as test fuels, and for varying foam solution flow rates 2, 2.5, and 3 gallons per minute gpm. Foam and solution properties detailed by military qualification testing were also measured and compared to a commercial AFFF. Solberg RF3 2018 and Fomtec Enviro 2-3 USP extinguished a gasoline pool fire in 49 and 78 seconds at a solution flow rate of 2 gpm. Commercial AFFF extinguished under the same conditions in under 30 seconds. Performance of the fluorine-free foams improved when the fuel was switched to heptane and when the solution application rate was increased from 2 gpm to 2.5 gpm with both fluorine-free foams extinguishing the fire in 31 seconds. Both fluorine-free foams had slower drainage and slower bubble coarsening than the commercial AFFF. However, foam properties collected do not appear to correlate well with extinction performance. Solberg RF3 and Fomtec Enviro 2-3 USP had concentrate viscosities of 26,000 and 16,000 cP, exhibited shear thinning of the concentrate, and had negative spreading coefficients. The inability of the foams and concentrates to meet critical extinction and property metrics for military qualification testing indicate the difficulties of utilizing these commercial products for Navy operations.
- Safety Engineering