The objective of this project is to develop per- and polyfluoroalkyl substance (PFAS)-free firefighting formulations that meet the performance characteristics of MIL-PRF-24385 and provide high performance fire-suppression against hydrocarbons and polar solvents, in extreme temperatures (32-125°F), and in salt or fresh water diluents.

The TDA Research (TDA) team is developing a 3% PFAS-free foam (3PFF) for MIL-PRF-24385 hydrocarbon fires. The team has demonstrated the performance of this foam in fresh and salt water against heptane and MoGas fires at the 10 ft² scale using a modified Underwriter Laboratories 162 protocol. They directly compared TDA 3PFF to two top-performing commercial PFFs (Firebull F3 and Solberg RF3) and found that the TDA foam is faster at controlling and extinguishing the fires, passes the torch tests (which demonstrates the foam long-term strength), and passed or was close to passing the 25% burn back tests. This formulation is still in development with support from the Air Force Small Business Innovation Research (AF SBIR) program and a revised formulation was able to extinguish a 28 ft² MilSpec fire in 43 seconds.

In this project, the research team will develop a non-toxic 3PFF concentrate to use against polar and nonpolar fuel fires by modifying the current 3PFF formulation for flammable alcohols, ethers, carbonyls (ketones, esters, aldehydes), and amines. This formulation will be appropriate for dilution in both fresh and salt water. The team will also formulate the foam to operate at temperature extremes of 32°F and 125°F. TDA will evaluate the optimized formulation in MIL-PRF-24385 tests under standard and extreme temperatures and with fresh and salt water sources. Specifically, TDA will evaluate foam quality (structure, stability, volume, drainage, spreadability), fire extinguishment time, and burn back time. Following a successful optimization and scale-up, TDA will collaborate with the Fairmount Fire Protection District (Golden, CO) to test the fire extinguishing properties of its improved concentrate formulations on 28 ft² solvent fires. Based on these tests, the team will scale-up its best performing improved formulation and have military collaborators at Tyndall Air Force Base (AFB) perform 28 ft² and 50 ft² validation tests under MIL-F-24385 conditions.

This project will result in surfactants with longer shelf lives and greater stability compared to other commercial siloxane surfactants, since limited shelf life is a well-known problem that plagues this class of compounds. The development of new PFAS-free foam (PFF) firefighting formulations will also enable sustained manufacture and use of fire suppression technologies by meeting environmental requirements while maintaining equivalent performance to ensure the safety of Department of Defense (DoD) personnel at airfields, onboard ships, and while deployed in extreme environments.