Aqueous Film Forming Foam (AFFF)

DoD’s R&D to Identify PFAS-free Firefighting Foam

The second facet of AFFF drawdown is DoD’s efforts to replace all AFFF (including short-chain) with PFAS-free fire-suppression technologies and techniques. One of the Department’s priorities is finding an effective PFAS-free firefighting solution that meets the life-saving performance standards of AFFF and does not have the negative health or environmental effects of fluorinated AFFF. The Department is investing significant resources in research, development, testing, and evaluation to identify alternative firefighting material and practices. DoD plans to fund over $70 million of research and demonstration projects on PFAS-free alternatives to AFFF for current projects underway.

PFAS Alternatives

The Department is researching and developing AFFF alternatives that do not contain PFAS through two key programs - Strategic Environmental Research and Development Program (SERDP), which focuses on basic and applied research, and the Environmental Security Technology Certification Program (ESTCP), which focuses on validating more mature technologies to transition them to widespread use.

Through SERDP/ESCTP, DoD has 20 active projects to develop formulations or additives that will either transition to demonstration projects or to better understand foam performance in support of future improvements to firefighting formulations. DoD has also tested over 40 unique formulations and additives using standard and experimental military delivery hardware.

The Department is also implementing a comprehensive, methodical process to evaluate and determine the most appropriate and feasible alternatives to replace fluorinated AFFF in our facilities, such as aircraft hangars and bulk fuel facilities.

Finally, the Department has also allocated resources for 6 research and demonstrations projects to investigate the ecotoxicology of PFAS-free alternatives using both commercially-available and developmental formulations.

Considerations for Firefighting Alternatives:An essential consideration is the ability of any AFFF substitutes to contain and extinguish fires rapidly and effectively. The technology must remain effective with misapplication, whether at half strength or at five times the recommended release. Alternatives must also be compatible with manufacturing and vendor capabilities as well as existing equipment and engineering. Research into the effectiveness of AFFF has shown that certain characteristics are vital to the effective application of any solution, including:

  • Fire extinguishing capacity;
  • Burn back performance;
  • Effectiveness with various fuel fires, including jet fuel and gasoline;
  • Foam transport;
  • Corrosivity;
  • Shelf life and aging; and
  • Scaling availability, among others.

Many of these technical characteristics overlap with the current MILSPEC, MIL-PRF-24385, which governs AFFF products and replacement technologies. The MILSPEC has been amended to limit concentrations of PFOS and PFOA and to remove the previously required fluorine component, paving the way for fluorine-free alternatives. Any AFFF replacement must still meet MILSPEC qualifications for physical characteristics, such as viscosity and stability. Alternatives will also undergo performance testing for extinguishment time; burn back time; misapplication; and Dry Chemical compatibility, among other specifications.

R&D of Viable PFAS-free Alternatives:The SERDP and ESTCP continue to jointly conduct rigorous research and demonstration testing for viable PFAS-free solutions. Fluorine-free foams are non-fluorinated, foam-based fire-suppression technologies. Some fluorine-free foams are available commercially, but have not yet been tested for MILSPEC qualification. Potential non-foam alternatives to AFFF also exist. Some of the most promising include an ignitable liquid drainage floor, high-expansion foam, trench nozzles, and water mist.

There are many viable alternatives for replacing AFFF, however, no single technology is suitable for every situation. The Department continues to evaluate all available technologies to find the best fit for each mission need and level of risk. For a summary of fluorine-free projects and final reports, see SERDP/ESCTP’s webpage of PFAS efforts.