The objective of this Statement of Need (SON) is to develop per- and polyfluoroalkyl substances (PFAS)-free firefighting formulations (i.e., fluorine free foams [F3]) for use with saltwater dilution that can extinguish class B fuel fires across multiple scenarios, particularly those involving Department of Defense (DoD) vessels and marine locations. Proposals should provide hypothesized reasons for reduced performance and/or incompatibility with saltwater dilution, propose methods to identify formulation rules to enable saltwater-diluted F3 fire extinguishing performance and compatibility, and propose and assess formulation solutions that will have good F3 performance with saltwater dilution. Proposed solutions should be relevant towards MIL-PRF-32725, Military Specification for Fire Extinguishing Agent, F3 Liquid Concentrate, for Land-Based, Fresh Water Applications. As such, key metrics for assessment are the following:
- F3 viscosities and expansion ratios upon saltwater dilution.
- Stability of F3 viscosities and expansion ratios after dilution in saltwater for a significant period of time.
- Corrosion of materials used in storage and deployment of F3 agents.
- Extinguishment time on gasoline and Jet A fuel for saltwater-diluted F3 agent.
- Burnback time on extinguished fuel fires of gasoline and Jet A fuel using F3 diluted with saltwater.
- Given that salt water is not a fixed concentration and many marine uses of F3 fuel fire suppressants would make use of brackish water, the effect of salinity level on performance should be examined.
- Toxicity of the F3 components and formulation and health hazard assessment classification of the formulation.
- The alternative should address key criteria including but not limited to:
- Reduce or eliminate the use of TSCA section 6 chemicals.1
- Reduction or elimination the use of CERCLA hazardous substances and emerging chemicals of concern2.
- Not contain the use of per- and polyfluoroalkyl substances (PFAS), perfluorinated oligomers, and polymers.3,4
Criteria of interest, but not required include:
- Firefighting operations conducted in extreme temperatures ranging from 32 degrees F to 125 degrees F.
- Firefighting operations involving various DoD-relevant fuels.
- Increased fire extinguishing capability at low aspiration and expansion rates.
- Improved spreading coefficients that approach or exceed legacy AFFFs.
- Concentrates that are compatible and can be mixed in tanks with other PFAS-free formulations.
- Assessing the reactivity of proposed F3 concentrates with common plumbing to gain insight into storability and compatibility with equipment on DoD vessels.
Proposals should address stability of the chemicals used to gain insight into storability and long-term effectiveness.
Proposals should include a plan to conduct a preliminary Life Cycle Analysis5 (LCA) to help indicate the life cycle cost benefit associated with the proposed process relative to current processes. Proposals should establish a lifecycle framework that can mature as the technology or process advances through the acquisition process. This tiered approach aims to develop and document a minimum data set at each stage of research and development that can be used to make informed decisions and streamline transition to an acquisition program. The LCA may include varying depths of data and information that can inform: the goal and scope of an analysis; the identity and quantity of relevant inputs and outputs to the system; and the estimation of life cycle impacts and costs.
Current PFAS-free firefighting formulations do not meet all the fire extinguishing requirements when diluted with saltwater. Insight into formulations rules to enable saltwater-diluted F3 fire extinguishing performance and compatibility and new PFAS-free firefighting formulations will enable formulation of sustainable F3 technologies while maintaining equivalent performance to ensure safety of DoD personnel on vessels.
Industry has developed PFAS-free alternative foams or F3s that meet fire performance or compatibility requirements for military applications with freshwater as specified in MIL-PRF-32725. However, no PFAS-free alternative or F3 has been developed to meet the specifications for military shipboard and marine use. F3 formulations have been found to be incompatible with saltwater dilution or have significantly reduced firefighting performance.
In shipboard use, firefighting agents are mixed with saltwater and flow through piping in the headers to the deck for firefighting. The diluted agent that remains in the headers can be there for months before its next use. As such, it is important that saltwater diluted F3s maintain acceptable viscosities, expansion ratios, and ultimately performance to reduce extinguishment time and maximize burnback time in firefighting applications without causing degradation to the piping.
Salt water and sea water are broad terms. As such, we recommend use of ASTM D1141 artificial seawater for experimental work.
John La Scala, Ph.D.
Program Manager for Weapons Systems and Platforms
Strategic Environmental Research and Development Program (SERDP)
john.j.lascala.civ@army.mil
