For fires involving ignitable liquids like gasoline, heptane, or isopropyl alcohol, water typically isn’t an effective form of suppression. Instead, Class B firefighting foams are a much more viable option. These foams form a film or sheet of bubbles on the surface of the ignitable liquid so that fuel vapors and oxygen can’t mix and combust into flames.
Currently, there are two main types of Class B firefighting foams on the market: fluorine-free foam and aqueous film-forming foam (AFFF). While these foams work to accomplish a similar goal, they’re quite different in their properties and functionality. We’ll discuss their distinguishing features below.
Fluorine-Free Foam vs. AFFF: What’s the Difference?
So what’s the difference between fluorine-free foam and AFFF? Let’s start with some definitions.
- Fluorine-free foam is a synthetic-based foam that contains surfactant blends and, in many cases, polysaccharides. It creates a blanket of bubbles above fire fuels and cools them to extinguish fires quickly.
- AFFF is a synthetic-based foam that contains fluorinated and hydrocarbon-based surfactants, including perfluoroalkyl or polyfluoroalkyl substances (PFAS). It creates a film that coats fire fuels, effectively suffocating them by creating a barrier to any oxygen, and cooling them to prevent hot fuels from reigniting. It’s long been the most popular and effective way to extinguish even the most challenging fires.
However, in recent years, studies have shown that the same properties that make AFFF so great at extinguishing fires also make them persistent in and harmful to the environment. This has led to extremely adverse health effects not only in the lands and waters that surround us, but also to human lives. For these reasons, many states have started to implement strict regulations on the use of AFFF. Some of them have even banned it altogether — making the go-to replacement option (you guessed it!) fluorine-free foam.
Fluorine-Free Foam — The Details
Now, let’s run through some of the unique characteristics and capabilities of fluorine-free foam, covering categories like composition, film formation, environmental effects, and legislative regulations.
- Composition – Fluorine-free foam is composed of water, solvents, and hydrocarbon surfactants. It doesn’t contain any PFAS.
- Film formation & performance – Since there aren’t any PFAS in fluorine-free foam, it doesn’t form an aqueous film to extinguish fires. Instead, it relies on a blanket of bubbles. This blanket of bubbles has been proven to be slightly less effective than AFFF’s film, so higher expansion rates and air-aspirating nozzles may be required to boost efficacy.
- Environmental & health effects – Fluorine-free foams are composed of substances with low environmental impact. In fact, many of them are completely biodegradable.
- Legislative regulations – Since fluorine-free foams have little to no environmental impact, it’s unlikely that they’ll be impacted by any legislative regulations or bans. If anything, more guidelines may be put in place for training, testing, discharging, and disposing of the foam.
AFFF — The Details
On the flipside, AFFF’s characteristics and capabilities are a bit different. Let’s take a look at its composition, film formation and performance, environmental and health effects, and legislative regulations.
- Composition – AFFF is composed of water, solvents, hydrocarbon surfactants, and PFAS.
- Film formation & performance – The PFAS in AFFF reduce surface and interfacial tension of the foam, enabling it to form an aqueous film on fire fuels. This film can be much more effective at lower expansion values, allowing for use in non-air-aspirating nozzles that offer greater reach.
- Environmental & health effects – The PFAS in AFFF don’t break down easily and may bioaccumulate. If not properly contained, PFAS can leak into groundwater and cause toxicity concerns for both the environment and human health. Researchers have only begun to uncover the harmful effects PFAS has had on human lives thus far.
- Legislative regulations – Due to the environmental and health concerns associated with AFFF and PFAS, some states have restricted the use of AFFF in specific applications, and other states have banned the use of AFFF completely.
Fluorine-Free Foam vs. AFFF: Which One Should Your Facility Use?
So between fluorine-free foam and AFFF, which one should your facility use for fire suppression? Well, fluorine-free foam requires more volume and special equipment to make it effective, but doesn’t pose any risk to the environment. On the other hand, AFFF is an incredibly effective extinguishing agent, but poses extreme risks to the environment and those who live within it.
Our answer? With all of the research done to show the harmful effects of AFFF and PFAS, it’s probably best to consider an AFFF alternative like fluorine-free foam. AFFF works well, can be stored safely, and can be disposed of cautiously to minimize impacts, but it shouldn’t be the predominant choice moving forward. Also, with many of the current and proposed regulations, it’s probable that states won’t even allow it in coming years. Fluorine-free foam can provide a safe, effective alternative — and it’s likely that more alternative options will become available in the future as well.
Need Help Making the Switch From AFFF to Fluorine-Free Foam? Contact Vanguard
We’re continuing to learn more about the dangers AFFF can bring to our communities. If you’re interested in making the transition from AFFF to fluorine-free foam, Vanguard Fire & Security Systems can help. We’ll listen to your facility’s unique needs, then propose an alternative solution that will work just as effectively to keep your property, products, and people safe. For more information, contact our team online.