Aqueous Film-Forming Foam, or AFFF for short, has lately generated significant debate. The background of AFFF firefighting foam, present problems, and future industry direction will be covered in this article. Initially, though, it’s crucial to make clear the main AFFF foam problem.

Polyfluoroalkyl chemicals, or PFAS, make up AFFF foam. Resilient to heat, water, grease, and oil, PFAS compounds are a class of manmade chemicals. The Environmental Protection Agency (EPA) has designated them as a “forever chemical” since the chemical accumulates in people, animals, and the surroundings and breaks down somewhat slowly. It is also classified as a likely human carcinogen. A higher cancer risk has been linked to exposure to PFAS chemicals in firefighters, airport employees, military personnel, and any other occupation closely related to AFFF.

Originally presented in the 1960s, AFFF was created by the United States Naval Research

Laboratory AFFF proved to be rather successful in extinguishing liquid fuel flames because of its low viscosity and quick spreading capability when sprayed. For this reason, the US government increased the use of AFFF in the 1970s at Department of Defense sites and military facilities, including bases and installations. Soon after, airports and municipal fire departments all over the country started using AFFF. Comprising almost 75% of the market, the United States military now uses firefighting foams most extensively nowadays. Local fire departments and petroleum processing refineries account for the rest of the market.

On US Navy vessels and aircraft carriers, AFFF proved to be quite efficient as a firefighting agent because of its rapid coverage of the fuel and vapor release from the flammable liquid. AFFF proved quite successful in rapidly smothering fires caused by either a fuel liquid spill or a collision, so medical responders could rapidly treat the pilot(s).

The fire tetrahedron notes that three elements—oxygen, heat, and fuel—must be present if a fire is to ignite. One calls this the flaming triangle. But a fourth element, the chemical chain reaction, must take place if a fire is to start and support combustion. We call this the fire tetrahedral. Remember that if you remove any of the four—oxygen, heat, fuel supply, or chemical chain reaction—a fire cannot start and/or support combustion. Over the surface of the liquid-fuel fire, AFFF foam forms a film that serves as a blanket, repressing the fuel vapor, therefore preventing the fire’s capacity to burn. 

The cooling and covering action of the film-forming foam stops heat and oxygen transfer. The blanket that the movie makes smothers the fire and traps the flammable vapors, breaking the chemical chain reaction. AFFF was quite successful in fire control and knockdown since it could spread rapidly across the liquid fuel. Sometimes the invisible film acting as a blanket over the combustible liquid causes a fire to be extinguished before the foam covers the liquid.

AFFF foam is known to include PFAS, a dangerous chemical with a likely relation to human carcinogenation. Therefore, one of the most often asked questions NFSA gets about AFFF is, What should we do with all the present AFFF systems installed? This is a really interesting subject, but sadly, there is no straightforward response to it. First of all, it is noteworthy that legislation demanding the elimination, replacement, or discontinued use of AFFF has not been passed by the United States Congress. Although this decision was made inside the Department of Defense and was not forced by Congress, the US Department of Defense has mandated all its facilities “turn off” all fire extinguishing equipment utilizing AFFF.

Still, over the past few years, some states have implemented legislation controlling the use of PFAS. States authorities in Maine, Minnesota, and Washington have been granted the power to forbid PFAS in diverse products. Twelve states—including California, Colorado, Connecticut, Hawaii, Illinois, Maine, Maryland, Minnesota, New Hampshire, New York, and Vermont—have already outlawed the sale of firefighting foam comprising PFAS.

If your state prohibits the sale of PFAS-containing firefighting foams, it may be necessary to replace current systems as they undergo hydrostatic testing. For more specifics, see Chapter 11 of NFPA 25. Existing AFFF systems must be replaced during hydrostatic testing due to restrictions on the sale of new AFFF foam in certain states.

If your state does not prohibit the sale of PFAS-containing firefighting foams, there is no need to replace existing installations as long as they are inspected, tested, and maintained according to manufacturer instructions and Chapter 11 of NFPA 25. Manufacturers of AFFF foam have halted production due to the upcoming phase-out and liability issues over AFFF and PFAS. In June 2023, 3M agreed to pay $10 billion in legal settlements over allegations that its firefighting foam contributed to PFAS contamination of drinking water. As many manufacturers no longer produce AFFF, it is likely that existing systems will need to be replaced owing to a lack of replacement components and equipment in the coming years. Existing installations will soon require hydrostatic testing, rendering it impossible to obtain new AFFF from manufacturers.

Several jurisdictions restrict PFAS chemicals used in firefighting and limit their outflow to prevent contamination of neighboring land. PFAS compounds have been identified in drinking water in the US.

Companies servicing existing AFFF systems must comply with NFPA 25’s mandate to conduct flow testing, especially since some states prohibit the use of AFFF foam outside of emergencies.

The International Fire Code (IFC) mandates foam systems to be inspected, tested, and maintained in line with NFPA 25.

Manufacturers are moving away from PFAS foam due to concerns about its long-term health and environmental impact. Synthetic fluorine-free foams (SFFFs) do not contain PFAS. As a result, negative effects on health and the environment are avoided. As previously indicated, AFFF foam separates fuel from oxygen by producing a thin aqueous film on its surface. In contrast, SFFF foams use bubbles to form a physical barrier between fuel and oxygen. This keeps the flames from spreading and provides a cooling effect. However, SFFF has some drawbacks. Fire protection system designers face practical challenges. SFFF foam manufacturers use different chemical and chemistry combinations to achieve their desired effectiveness. Not all SFFF foams are created equal. Manufacturers have different criteria for application density and percentage rates. Each has unique strengths and weaknesses depending on the fire type, fuel, and size. Existing fire prevention systems using AFFF may require modifications or replacement to accommodate modern SFFF foams.

The same freeze protection that AFFF foam offers is not offered by SFFF foam. Understanding the differences between SFFF and AFFF foams is crucial for fire prevention system designers and firefighters.

Consider the following while choosing the right foam for your application. As the shift from AFFF to other foams continues, consider the following guidelines:

1. What do you want to protect?
2. Is existing equipment compatible with the new foam?

To decide on a course of action, both questions have to be addressed. Look at available foam formulations, considering expansion rate, drainage time, and cooling capacity.

For almost ten years, foam producers have been experimenting and creating alternatives for AFFF. One can find several non-fluorine foam products on the market. Industry evaluated new fluorine-free solutions and the US Department of Defense Fire Protection Research Foundation found they successfully extinguish liquid fuel fires. Manufacturer, fuel type, and discharge technique all affect the behavior of foam products free of fluorine. AFFF’s success stems from its capacity to create a film layer covering burning gasoline. Unlike AFFF, fluorine-free foams produce a bubble barrier that prevents fuel vapours from mixing with oxygen, so instead of leaving a film on the fuel they block. Thus, there isn’t a “one size fits all” fix for substituting AFFF. 

Contractors and public safety organizations face the challenge of appropriately disposing of AFFF after replacement. While some states provide free disposal of AFFF, it is typically limited to fire departments and other public safety agencies. Contractors should be prepared to handle disposal fees, which can reach $20 per gallon.

In summary, replacing old AFFF fire prevention systems has been a long-standing worry that is unlikely to be resolved soon.

Manufacturers have halted selling AFFF (or PFAS), making it challenging for enterprises to maintain these systems in the future months and years, even if their state has not established laws outlawing them. It’s inevitable that fire prevention specialists will need to consider when and how to replace current AFFF systems.