Each airport must retain a certain amount of fire extinguishing agent at any given time. That agent, aqueous film-forming foam (AFFF), is a highly effective combatant to liquid pool fires.

AFFF are called “film-forming” because, even after the foam has dissolved, a watery layer remains, coating the liquid pool surface and creating a barrier that suppresses and extinguishes a fire. Fluorine and hydrogen-based substances reduce water surface tension to allow for formation of this aqueous film.

In recent years, though, concern has grown around potential health and environmental impacts of certain fluorinated chemicals found in AFFF, PFAS. Two specific PFAS, PFOS and PFOA, are under study for their bio-accumulative, persistent, and toxic nature. A desire to phase out these chemicals led the FAA Reauthorization Act of 2018 to direct that, in three years, the FAA cease requiring fluorinated chemicals in AFFF in order to meet fire performance standards. This order begs the integration of sound alternatives so that ARFF operations can continue to effectively serve airports. Fluorine-free foam (FFF) formulas show potential to replace current AFFFs but are not yet proven to possess equal capabilities.

To that end, the FAA Office of Airport Safety and Standards has asked ATR to help evaluate FFFs and develop standards for their use at airports. First, ATR will identify commercially available FFFs and FFFs used in military and airport applications around the world by conducting a literature review. Next, chemical analysis will test compatibility among FFF candidates. Since ARFF departments may currently mix AFFF concentrates from different foam vendors with no adverse effect, incompatibility could mean strict adherence to a single manufacturer or risk of cross contamination. Finally, select concentrates will undergo fire extinguishment performance testing for comparison against fluorinated AFFF. Integration processes will be developed for FFF(s) that meet all performance requirements.

Contact Project Lead Keith Bagot