The goal of this project was to develop and publish a new fluorine-free foam (F3) military specification (MILSPEC) applicable for all Department of Defense (DoD) land-based military installations in accordance with the requirements and timeline established by the FY20 National Defense Authorization Act. The Phase I portion of the program provided the opportunity to fully assess the commercially available F3 capabilities and provide the requisite data set for use during the development of the specification (Phase II). As a result of this effort, the F3 MILSPEC serial number (MIL-PRF-32725) was assigned and dated 06 January 2023 and the new MIL-PRF-32725 “FIRE EXTINGUISHING AGENT, FLUORINE-FREE FOAM (F3) LIQUID CONCENTRATE, FOR LAND-BASED, FRESH WATER APPLICATIONS” was published and then made publicly available via the Defense Logistics Agency ASSIST database on 12 January 2023.

Technology Description

This project was executed in two phases as described below:

  • Collect a comprehensive firefighting performance and chemical/physical properties data set for the selected commercially available F3 products.
  • Conduct a detailed analysis of the collected data to determine the parameters that could be used to qualify F3 firefighting agents for DoD land-based military applications. Based on this analysis, a draft F3 MILSPEC was prepared for the Naval Sea Systems Command to serve as the starting point for the development/writing process.

Prior to the start of the project, there were several variables that were defined to provide the focus of this effort. Specifically, since the hazards associated with land-based DoD applications are primarily Aircraft Rescue and Fire-Fighting uses, the capabilities of the F3s would be assessed against aviation fuel fires (Jet A and JP-8) as well as ethanol-free gasoline used in the aqueous film forming foam (AFFF) MILSPEC (MIL-PRF-24385F).

Demonstration Results

The F3 fire performance data provided the baseline for the criteria used in the F3 MILSPEC development.

  • The fire extinguishing capabilities of the leading commercially available F3s were less than that of MILSPEC AFFFs. Specifically, none of five selected F3s could meet the AFFF MILSPEC fire extinguishing performance requirements as currently written. This finding was not surprising since the F3 product's surfactants were hydrocarbon-based and not oleophobic, like the fluorocarbon-based surfactants found in AFFF, allowing more vapor transport through the foam blanket to the fire.
  • It was determined that all five F3s had similar fire extinguishment capabilities against the 28ft2 fire tests.
  • The Newtonian F3s had reduced burnback resistance capability for the gasoline fueled fires in comparison to AFFF and the non-Newtonian F3s. However, the burnback resistance of the Newtonian F3 products were still considered adequate for DoD land-based applications.
  • All five F3s demonstrated consistent fire extinguishing capabilities over the range of concentrations from half strength to quintuple strength solutions.
  • All five F3s demonstrated fairly consistent fire extinguishing capabilities with reduced aspiration.
  • None of the five F3s showed any signs of degradation in fire extinguishing capability when the foam concentrate was aged before use.

Implementation Issues

Although the fire extinguishing capabilities of the existing MILSPEC F3s were somewhat less in comparison to MILSPEC AFFFs, their demonstrated performance capabilities were deemed sufficient to meet all the land-based DoD end-user requirements. This declaration in firefighting performance sufficiency has been further validated during the WP21-3461/WP21-3465 Phase I-IV Large-Scale PFAS-Free Firefighting Performance testing conducted at the Naval Air Warfare Center Weapons Division China Lake fire test facility using both U.S. Navy handline and foam turret foam delivery firefighting equipment.