- Program Areas
- Installation Energy and Water
- Environmental Restoration
- Munitions Response
- Resource Conservation and Resiliency
- Weapons Systems and Platforms
Fluorine-Free Aqueous Film Forming Foam
Dr. John Payne | National Foam
The environmental issue to be addressed in this project is the use of fluorosurfactants and fluoropolymers in aqueous filmforming foams (AFFF) for fire suppression. All foams that meet the requirements of MIL-F 24385 must contain fluorocarbons. Older formulations contain C8, newer products have shorter C6 fluorocarbon chains. C6 fluorocarbons are persistent in the environment, but their toxicology to humans and aquatic species is considered more benign than C8. A fire-fighting foam that genuinely biodegrades in the natural environment would eliminate any future concerns.
The objective of this project is to use scientific methods to increase understanding of the physical and
chemical processes that underlie fire-fighting foams, and how the components of a foam formulation can deliver the properties required for good fire performance whilst minimizing environmental burdens. Statistical methods will be employed to develop a fluorine-free surfactant formulation that meets the performance requirements defined in MIL-F 24385.
A life cycle assessment will compare the environmental impact of each foam type and identify routes to improving environmental performance.
The generation and deployment of fluorine-free fire-fighting foam will be broken down into individual stages. For key stages, the desirable physical properties will be hypothesized and tested with small-scale laboratory tests that give quantitative data suitable for statistical analysis. The project aims to understand the relationships determining:
Surfactant formulation --> surface chemistry --> foam physical properties --> fire performance.
All surfactants will be tested during the understanding phase, but product development will be limited to existing readily biodegradable surfactants, solvents, polymers and other additives
Much emphasis will be on fire performance, and in particular the known weaknesses of fluorine-free foams: fuel pick-up on application; poor vapor suppression leading to short burnback times; performance in sea water and the incompatibility with unaspirated devices. A full life cycle analysis of various classes of firefighting foams will be carried out using the method described in ISO 14040 and 14044. The fate and transport pathways of glycol or glycol ether solvents, their volatilization, global warming potential (GWP), migration in water and degradation processes will be investigated.
A better understanding of the role of surfactant and surfactant blends, solvents and other additives in delivering the properties required of a fire-fighting foam will help the scientific community in improving performance and environmental profile of foams. A fluorine-free foam that genuinely meets the fire performance standards of AFFF will ensure the safety of Department of Defense (DoD) personnel and assets without adverse environmental impacts. Life cycle analysis will identify areas where further environmental improvements can be made.