This project will identify and test functional additives in mature and emerging per- and polyfluoroalkyl substance (PFAS)-free fire suppressants to enhance fire-suppression performance for military use. While PFAS are a common ingredient in fire extinguishers and especially in aqueous film-forming foams (AFFF) due to their stability at elevated temperatures and oleophobicity, the National Defense Authorization Act has ordered their use to be phased out by 2024. Additives and non-PFAS containing AFFFs will be evaluated for their chemical and physical properties, as well as for their firefighting on-scale performance and flammability by co-performers at Jensen Hughes, an established fire-protection engineering firm.

This work will include a thorough study of selected green additives, with a focus on assessing oleophobic compounds as PFAS replacement materials. Johns Hopkins University Applied Physics Laboratory will lead experiments to assess the chemical and physical properties of the additives, where surface and interfacial tension between the fuel and the foam layer are of prime interest. A surface tensiometer and viscometer will be employed to test the physical characteristics of the additive foam mixtures, building on experience in producing blast mitigation foams. Jensen Hughes will lead evaluation of foam additives at large scale to assess performance against currently used AFFF controls in accordance with MIL-PRF-24385.

This fundamental work will identify a path forward for PFAS-free fire suppressants that maintain or augment the performance of current military foams. This transition is essential because of the known risks of PFAS including bio-accumulation, environmental persistence, and detrimental health effects. This study will identify novel additive mixtures to enhance green foams in accordance with military performance requirements, reducing the use of undesirable fluorosurfactants. All additives explored will enable the military to meet new regulations restricting the use of PFAS while maintaining operational safety. Future work will build on these explorations with industry partners, including further testing and scalable production methods.