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ESTCP, Weapons Systems and Platforms Program Area
Released January 7, 2021
Closed March 4, 2021
The Department of Defense’s (DoD) goal was to eliminate per and polyfluoroalkyl substances (PFAS) from firefighting formulations as soon as possible. Towards this end, projects were sought to demonstrate and validate more environmentally sustainable PFAS-free fire suppression alternatives against the current performance requirements outlined in MIL-PRF-24385F (SH) with interim amendment 3. The intent of this solicitation was to determine the maximum available performance using mature PFAS-free firefighting agents against the current military requirements and uses. The following considerations were of interest:
Due to the expense of large scale testing, only PFAS-free fire suppression alternatives that demonstrate promise based on initial small scale testing (28 ft2 and 50 ft2 tests of the current MILSPEC) are of interest for large scale demonstrations. Information on the historical 1260 ft2 pool fire test is available in Section 4.7.7.3 of MIL-F-24385B.
The materials and processes demonstrated/validated should have already been developed to at least a Technology Readiness Level (TRL) of 4, and the proposed project should bring them to TRL 7 or higher. Alternative formulations should have been in production-level materials rather than laboratory-scale samples. Projects must have demonstrated producibility, defined as the ability to be produced in the near term to meet the current DoD airfield or shipboard use requirement.
Field testing in military relevant environments should have been included in the proposed project. Alternative formulations must have been compatible with generally used storage equipment (e.g., polyethylene) and piping (steel, copper-nickel, bronze alloys), while providing comparable corrosion rates to current AFFF. Formulations should have met requirements with fresh and salt water at multiple delivered concentrations. In addition, formulation stability must have been demonstrated. Proposals should have included approaches to demonstrate similar correlation between large and small scale fire tests with PFAS-free fire suppression alternatives, in lieu of large scale tests.
Proposals should have included an assessment of the human health and environmental impacts of proposed ingredients, formulations, and byproducts if such testing has not already been completed. This should expand on commonly used aquatic toxicity, chemical oxygen demand and biodegradability testing required in the MIL-PRF- 24385F. These proposals should have established a baseline lifecycle framework and identified the lifecycle inventory elements currently known, those to be investigated during the project, and those beyond the scope of the proposed work. Any completed testing on human health and environmental impacts of proposed ingredients, formulations, and byproducts should have been summarized in the proposal.
All projects should have involved at least one DoD organization as a funded co-performer that was considered a stakeholder for the intended application. Proposals should have also indicated the involvement of other DoD stakeholders at the consultant level and higher.
Funded projects will appear below as project overviews are posted to the website.
AFFF is a water-based foam used by the military since the 1970s for fire suppression in ships, shore fixed systems, aircraft hangars, and to extinguish liquid fuel fires. AFFF mixtures containing significant quantities of perfluorooctane sulfonate (PFOS) and related perfluoroalkyl sulfonates were in use until 2002, when production stopped; however, the DoD continued to use PFOS- containing AFFF stocks for some time after the halt in production. It is estimated that there are still over 500,000 gallons of PFOS-based AFFF in stock in the DoD inventory. The Air Force and Navy are the primary users for AFFF, with an estimated current stockpile of 423,000 and 97,000 gallons, respectively.
New AFFF formulations with telomer-based, short-chain fluorosurfactants (C6 or shorter) have been shown to have a reduced environmental impact. However, these materials still have the potential to persist in the environment or even to contain trace quantities of PFOS or perfluorooctanoic acid (PFOA). The current specification, MIL-PRF-24385F (SH) w/ interim amendment 3, does not require the presence of a fluorocarbon surfactant, and sets a maximum allowable content for PFOA and PFOS. Current regulations for the short-chain compounds are less strict, but it is uncertain what the long-term environmental remediation requirements may be for these materials.
Since 2006, use of AFFF containing PFOS and PFOA has generally been replaced by foams that have fluorosurfactants of 6 carbons or fewer. These newer foams are thought to be less toxic and biopersistant and bioaccumulative, though concerns remain.
The 2020 National Defense Authorization Act requires that the DoD publish a new military specification for PFAS-free foam by 31 January 2023 and that PFAS-free foam be available for use by 1 October 2023. In addition, the procurement and use of fluorinated AFFF would be prohibited after 1 October 2023 and 1 October 2024 respectively.
Industry has identified potential PFAS-free alternative foams; however, none of these technologies meet the fire performance or intercompatability required for military applications. MIL-PRF-24385 requires the DoD to evaluate AFFF for foamability and sealability using specific test conditions (nozzles and application rate) to meet specific fire extinguishment and burn back times. Many PFAS-free alternatives can be used to extinguish pool fires, but do not meet the strict requirements outlined in MIL-PRF-24385F (SH) w/ interim amendment 3.
This problem is not unique to military operations. Civil aviation continues to use AFFF or fluorosurfactant-free fire suppression foams that do not meet the performance of AFFF. Alternatives that meet or exceed current AFFF performance requirements without fluorosurfactants would dramatically reduce the environmental impact of fire suppression training and operations while maintaining the safety of personnel at crash sites or around liquid poolfires.