Capabilities Assessment of Commercially Available PFAS-free Foams
ESTCP 2021 Project of the Year Award for Weapons Systems and Platforms
Aqueous film-forming foam (AFFF) is a water-based firefighting agent used by the military since the 1970s for fire suppression in ships, shore fixed systems, aircraft hangers, and to extinguish liquid fuel fires. The Department of Defense (DoD) primarily used AFFF mixtures containing significant quantities of perfluorooctane sulfonate (PFOS) and related perfluoroalkyl sulfonates which are part of a larger group of manufactured chemicals widely known as per- and polyfluoroalkyl substances (PFAS). While AFFF that contains PFOS is no longer produced, a substantial quantity remains in the DoD’s inventory. As a result of the use of legacy AFFF for fire suppression, multiple DoD installations have detected PFOS and perfluorooctanoic acid (PFOA) contamination at 3 to 4 orders of magnitude greater than the current EPA health advisory. Potential fluorine-free alternative foams have been identified, however, none currently meet the performance required for military applications.
To address this issue, Mr. Jerry Back and his team from Jensen Hughes and the Naval Research Laboratory set out to identify an environmentally acceptable, PFAS-free firefighting formulation that met the performance of the legacy fire suppression foam. Specifically, the team made direct comparisons of the performance of currently available PFAS-free firefighting formulations with the legacy technology. The capabilities were assessed at both approval and real-scale test scenarios.
The results of this project have helped DoD take a step towards the elimination of firefighting foams that contain PFAS. The team preformed a literature search to identify 40 PFAS-free firefighting formulations for further evaluation. Each of these agents were assessed to determine whether there were any environmental concerns that would preclude them from further evaluation. The firefighting capabilities of the selected alternatives were evaluated using the same equipment and test personnel that typically perform the military specification and qualified product list approval tests. The top five PFAS-free firefighting formulations demonstrated good capabilities against both gasoline and Jet A fires and were selected for further evaluation. This group included three Newtonian, low viscosity concentrates and two non-Newtonian, high viscosity concentrates. The firefighting capabilities of the top fluorine free foams and agents were assessed against a real-scale, representative manual firefighting scenario using a fire hose to extinguish a 400 ft2 pool fire. The initial tests were conducted with the legacy AFFF to provide a baseline for comparison and to allow the firefighting party the opportunity to optimize their procedures and tactics. Results of the testing showed that, the top five PFAS-free firefighting formulations required about 1.5-2 times longer to extinguish the fires than the legacy AFFF. However, all the fires were quickly controlled and ultimately extinguished with the performance difference measured in seconds or fractions of minutes. The information derived from this project will also be used to develop specifications for future PFAS-free firefighting formulations.
Through their efforts on the project Capabilities Assessment of Commercially Available Fluorine-Free Foams, Mr. Jerry Back and his team have been awarded the 2021 ESTCP Project of the Year for the Weapons Systems and Platforms Program Area.
- Jerry Back – Jensen Hughes
- John Farley – Naval Research Laboratory