This is a follow-up to our November 2020 article on the development of fluorine free firefighting foams, Comparison Testing of the New “Fluorine Free” Firefighting Foams.
AFFF: Aqueous film forming foam
For over half a century now, aqueous film forming foam, or AFFF, has been the answer for how to extinguish ignitable liquid fires due to its ability to suffocate these types of fires. AFFF is now being rapidly phased out due to its environmental and health concerns.
There has been rapid movement around the world to limit or ban the use of foams containing fluorine. In 2021, the number of states in the US that banned or severely limited AFFF increased to at least 15, and legislation is pending in at least five other states to do the same. Several European countries have already stopped using AFFF, and in February the European Chemicals Agency proposed an outright ban on the manufacture, use, and export of AFFF for the European Union.
The US military, which helped develop AFFF, has announced plans to stop using it by October 2024, and the Federal Aviation Administration intends to follow suit at airports across the country.
Possible replacements: Are they effective?
As discussed in our 2020 article, foam manufacturers have been working on possible replacements for AFFF for several years, and there are now several dozen foam products on the market that claim to be made without fluorine.
Extensive testing by the Fire Protection Research Foundation, the US Department of Defense, and the petroleum industry research group LASTFIRE has shown that many of these new products can be effective at extinguishing ignitable liquid fires; however, unlike AFFF, the effectiveness of fluorine-free foam is dependent on numerous factors and complexities.
The new foams are not drop-in replacements for AFFF; they have different characteristics and use different methods for putting out the fire. In addition, the various fluorine-free foams themselves vary from one to the next ranging from dramatically different viscosities, the types of burning fuel they can protect/extinguish, how aspirated the foam is, and the discharge devices used.
AFFF has a viscosity similar to water; however, some fluorine-free concentrates have a consistency more like ketchup. Existing AFFF equipment is not calibrated to handle these viscosities. The manufacturers continue tweaking their formulations and making them better. Some manufacturers even claim to have developed fluorine-free foam concentrates with low enough viscosities to work with minimal changes to existing infrastructure.
Even when all of these factors are designed and applied correctly, it can still take twice as much foam, and twice as long, to extinguish the ignitable liquid fire as it does with AFFF.
Why the delay?
Recognizing an urgent need for guidance, the Fire Protection Research Foundation published a report in May of this year, Firefighting Foams: Fire Service Roadmap, which aims to help fire departments understand the considerations for choosing a foam to replace AFFF, as well as the numerous factors that will go along with it. Although this roadmap was aimed at fire departments, much of the information is applicable/informative to industry/corporate users of AFFF as well.
One of the things emphasized in this roadmap document is that the end user, independent of who it is, is going to need to do their homework.
Choosing which fluorine-free foam to use among the myriad of options available is just the first step. After that comes a whole list of other issues, such as how to dispose of the old AFFF, how to decontaminate old equipment, and what new equipment might be necessary.
The US Department of Defense has its own performance specification for firefighting foams on its bases, referred to as a MIL-SPEC, which includes being able to extinguish a fuel fire in less than 30 seconds. To this point, not one of the dozens of new foams has managed to pass each part of the rigorous test, and as a result, no FAA-regulated airports or military facilities have yet converted away from AFFF. A new MIL-SPEC regulation is now being written which will allow for acceptance of fluorine-free foams.
Fluorine-free foams on the market
Although the military has yet to officially approve a fluorine-free foam for use at its facilities, there are now a few dozen products that have passed performance tests developed by credible testing and approval authorities, such as Underwriters Laboratories. Of the several dozen fluorine-free foam products now on the market, about half have credible approvals/listings, according to the Research Foundation’s roadmap report.
The NFPA standards that address foam suppression, such as NFPA 11, Standard for Low-, Medium-, and High-Expansion Foam, and NFPA 30, Flammable and Combustible Liquids Code, as well as NFPA’s standards for the protection of airport facilities, focus mainly on hardware and do not specify which type of foam can or should be used. As such, little has changed so far in the NFPA standards regarding the transition to fluorine-free foam, other than adding information about the new foams in the Annex. Since the new foam concentrates are still undergoing testing, there hasn’t yet been a need for significant changes to the design or protection strategies outlined in NFPA 11 for fixed-system foam application.
Industry/corporate users of AFFF will need to make an informed decision about transitioning to a fluorine-free foam and disposing of legacy AFFF. In some cases, State legislation will set a clear timeline for this transition. In other cases, the users may consider a preemptive transition ahead of potential Federal or State regulation.
There is no doubt that this issue is full of questions and complications, but we must face the fact that this transition is going to happen.