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There are numerous choices of firefighting foam products in the market. As important as it is to understand the hazards we aim to protect, we should put forth as much effort into the understanding of the products chosen or recommended for protecting these hazards.
There are several choices in the firefighting foam market: Class A foams, high expansion foams, fluorine-free foams (F3) and aqueous film-forming foams (AFFF). We will focus on AFFF and dive into its uses and restrictions as the product line has been under immense pressure environmentally.
AFFF agents were first developed in the early 1960s by the U.S. Navy. The new synthetic firefighting foam formulation provided superior performance over the protein-based foams of the time. AFFF outperformed the existing product offerings on many levels of performance, including its surface tension, which gave it the ability to spread across a Class B fuel surface far better than protein-based agents and with less aspiration required.
This synthetic product proved itself in many applications over protein-based products and, before long, was the primary choice with Class B hazards over the protein-based predecessor. During this time, protein-based foam formulations were being modified with fluorinated surfactants to improve performance but were still off the mark as compared to the AFFF formulation.
The next 50 years saw vast improvements and development of AFFF. A significant development was the reduced proportioning rates from 6 percent to the industry standard of 3 percent and even 1 percent. Each of these proportioning rates offers incredible firefighting performance with progressively better efficiency in use.
This improvement in proportioning percentage lead to smaller foam tank sizes, which improved the overall footprint impact of systems. It also improved the overall cost of systems, along with system maintenance costs over its expected lifetime. This was just as beneficial to fire responders and resulted in less product needed on response vehicles or trailers containing foam.
Though AFFF was very effective on hydrocarbon-based Class B hazards, it was found to break down when used on polar solvent-based Class B hazards. Thus, alcohol-resistant AFFF (AR-AFFF) was formulated with special gum additives to form a membrane that would allow the foam solution to be effective on polar solvents.
These foams were still useful on hydrocarbons and often identified by their split-proportioning rations; for example, 1x3, 3x3, 3x6. The first number identified the proportioning rate for a hydrocarbon and the second number a polar solvent. With the addition of AR-AFFF to the fluorinated foam agent family, these products proved very versatile with Class B hazards.
The efficiency of AFFF goes without saying for densities as low as 0.10 on type I and II discharge devices and 0.16 on most standard sprinklers. It is also very effective, however, at low expansion ratios, yet stable enough to be used in medium expansion ratios with specific discharge devices. Per NFPA 11, low, medium and high ratios are defined as the following; low <20, medium 20-200 and high >200.
The most notable strength of AFFF is its ability to control and suppress in-depth Class B hazards. An in-depth application is classified as a fuel depth of at least 1 inch or more per NFPA 11 and 30. Many of the other foam products outside of the AFFF family can be effective on most spill or non-in-depth applications. However, current nonfluorinated products used on in-depth applications tend to require higher densities and longer durations in some cases. They also need more aspiration or expansion to perform without fluorinations.
Keep in mind that the development of F3 products is the top priority of every foam manufacturer at this time. This will be a rapidly evolving product for which I will explain here further.
Short Chain vs. Long Chain
Let’s move through AFFF’s history to 2006, where the perfluorooctanoic acid (PFOA) product stewardship program was put into motion. The U.S. Environmental Association worked with eight of the leading producers in the per- and polyfluoroalkyl (PFAS) substances market. This global program was to achieve a 95 percent reduction in emission of PFOA by no later than 2010 and commit to working toward the elimination of these emissions and products by 2015.
Another targeted chemical within this program is perfluorooctane sulfonic acid (PFOS). It has not been manufactured in the United States since 2002; this includes importing per chemical data reporting efforts in 2006 and 2012. These are bio-persistent chemicals in the environment and the human body that don’t break down, as well as accumulate over time.
The direction was then taken to reduce the carbon chain molecule of all AFFF formulations of eight or more down to what is known as a short chain of six or less. At the time, this was the solution to eliminate or significantly reduce PFOS/PFOA in the formulations and thus brought forth the latest advancement in AFFF chemistry, the designation of C6 AFFF formulations.
This new short-chain formulation requirement was required of all foam manufacturers by Jan. 1, 2016. The products were released to the market with C6 nomenclature by manufacturers. It was a massive effort to develop and list equipment and devices to meet the needs of the market with comparable performance to the longer-chain formulations. The shorter-chain chemistry proved challenging in trying to equal the performance of the previous long-chain formulations.
All in all, it was completed quite successfully and was thought to be a huge step forward in taking AFFF into the future with the environment in mind.
Environmental Hazard, Legislative Reaction
This was just the tip of the iceberg with environmental impact during this transition. Following it were discoveries of groundwater contamination surfacing around the country. Many of these locations were near airports and military sites, which tend to have many facilities and hazards that require protection of Class B hazards.
The response vehicles and personnel at these locations trained and tested their equipment often, most times even weekly. These test areas historically would be in a location nearby and out of the way but exposed to possible environmental impacts and not in a self-contained area, which proved to have a significant effect at these locations.
New York was one of the first states to issue a notice of limitation of release of these fluorochemicals, known as the NYDEC PFOA/PFOS Regulation. It has since been superseded, as additional states began passing legislation specifically around the restriction of PFAS (perfluoroalkyl and polyfluoroalkyl) substances — a group of about 5,000 synthetic organic compounds and found in commonly used products, AFFF being one of them.
My home state of Washington led the way with HB 6413 signed into law on March 5, 2018. It banned the use of firefighting agents containing PFAS for training purposes, effective July 1, 2018. This legislation also prohibited the sale of any foam agent containing PFAS to be sold in Washington state, beginning July 1, 2020. There are some exemptions to the law for fuel terminals, chemical manufacturing and federal locations (FAA, U.S. military sites).
The state moved quickly to pass the legislation with little opposition and laid the groundwork for several PFAS bans and restrictions across the country. Currently, there are five other states with bills that have been passed into law with PFAS bans, including Minnesota, Colorado, Maine, New Hampshire and New York. These laws have similar exemptions, as noted in Washington’s bill language, and most have effective dates on or around January 2022.
Numerous states are proposing bills or have PFAS water-impact bills in place that allocate funds for testing, as well. The takeaway here is that there is an immense amount of pressure to move away from fluorochemical agents such as AFFF.
The National Defense Authorization Act was signed into law Dec. 20, 2019, by President Donald Trump. It addresses the steps that will be taking place related to PFAS contamination monitoring, reporting and cleanup. This also will end the use of AFFF within the Department of Defense, with an aggressive timeline to publish new PFAS-free specifications for military installations by Oct. 1, 2023. The DOD will be required to phase out the use of AFFF at all military facilities by Oct. 1, 2024, with some exceptions.
This is a significant decision and it will take a massive effort to achieve. Manufacturers of F3 products will be challenged to provide a product that can come even close to the type of protection AFFF could provide. Some notable performance requirements of Mil-Spec AFFF were to achieve military extinguishment standards at half the proportioning rate and twice its proportioning rate. They must be able to be mixed with another manufacturer’s Mil-Spec AFFF product and perform. I suspect these may be modified to accommodate an F3 solution to AFFF within the DOD.
Providing a solution for a Class B hazard today is very challenging. Currently, environmental pressures are making us reluctant to consider AFFF, but is there an alternative that can meet the needs of the application? AFFF is still a viable solution and, in some cases, still the best solution. Designing systems with minimal impact on the environment should be considered at all times using measures to contain discharges if they occur, whether it is for testing or an actual fire event.
Evaluate all hazards and risks involved when providing fire protection solutions for Class B hazard applications. We may not be able to avoid all environmental impacts from fires, fuel spills and foam discharges, but we can do our best to minimize them.
As industry professionals, we’re tasked with providing fire protection solutions with many challenges to overcome throughout the process. Going forward, we must pay close attention to state regulations, DOD criteria and, of course, product listings related to Class B application to provide a fire-safe world.