The objective of this project is to look at commercial, off the shelf (COTS) fluorine free aqueous film forming foams (FF_AFFF) to determine where they fall short of MIL-PRF24385F specifications, and to determine if commonly available firefighting engineering technology such as compressed air foam (CAF) or ultra-high pressure (UHP), and/or minor chemical modifications, will allow the foams to meet the required standards of extinguishment and burnback times.
Several COTS FF_AFFF are available, but currently none of them meet the very stringent MIL-PRF-24385F specifications, generally in either the extinguishment time (30 seconds) and/or burnback time (360 seconds) requirements. It is known that extinguishment and burnback times can be altered by affecting the quality of the foam produced. Both CAF and UHP are known to affect foam formation, and by adjusting the amount of air injection, pressure, and flow rates, one can choose the foam quality necessary (balancing spreadability with longevity) to extinguish a fire. Solutions to this problem can be 1) chemical, i.e. taking dry agents that are not normally soluble in water and combining them with the FF_AFFF, or 2) physical, i.e. increasing the loading of FF_AFFF into solution with UHP system than would be possible in a traditional low pressure system. Additionally, minor issues such as slightly higher than acceptable corrosion rates could be addressed by the manufacturer by simple formula changes, such as adding a corrosion inhibitor. By combining both the engineering and the chemical solutions, it is expected that one or more FF_AFFF could be modified to meet the standards of MIL-PRF-24385F, thus allowing the U.S. military to switch to a more environmentally friendly firefighting agent. Some branches of the U.S. military are already advocating for particular brands/formulations of environmentally friendly COTS firefighting agents. By conducting this work, the project would be eliminating such bias and evaluating several different potential FF_AFFF against both MIL-PRF-24385F and each other, and determining which best fit the Department of Defense’s (DoD's) needs.
The expected DoD benefits from validating and demonstrating a viable AFFF alternative that is fluorine free are (a) significant DoD operational and maintenance cost savings and (b) a reduction in environmental risk. A preliminary economic analysis indicates that FF_AFFF are ~10 to 20% cheaper than equivalent MIL-PRF-24385F grade fluorine based concentrates. A 2011 study estimated that the DoD expends 157,000 gallons of AFFF concentrate per year, suggesting a potential savings of the DoD between $1.4 to $2 million annually in foam purchase costs alone. Savings would also be realized on the reduced need for compliance and remediation. The expected Technology Readiness Level (TRL) after completion of this project is 8/9, which will allow immediate implementation of the successful FF_AFFs DoD wide, thus helping to meet the National Defense Authorization Act (NDAA) passed by Congress in 2017 requiring that the military look into foam alternatives that do not contain PFOS/PFOA. Additionally, this technology demonstration/validation will greatly help civil aviation reduce the environmental impact via use of fluorine-free AFFFs that meet or exceed the performance of currently used fire suppressants.