People tasked with extinguishing flammable liquid fires have known the limitations of water as a fire suppressant for years.

The pursuit for a better solution led Russian chemist Aleksandr Loran to develop and introduce in 1902 the first firefighting foam for flammable liquid/oil fires, after witnessing thedestruction they caused in his hometown. 

The foam is used to create a foam blanket, which has lower density than water and floats on top of the fuel surface separating the flammable liquid from oxygen.

Through the years, technological innovations have improved on the effectiveness of firefighting foam.

While the advancements to foam technology helped firefighters to save thousands of lives over the years, they sometimes also brought unwelcome properties that had an impact on the environment. 

Emergence of Aqueous Film Forming Foam

Aqueous Film Forming Foam (AFFF) containing PFAS (per- or polyfluoroalkyl substance) were introduced in the mid-1960s, first commercialised in the early 1970s, and have served as the industry workhorse ever since.

PFAS is a term used to describe a broad category of fluorochemicals (polymers and non-polymers) of different carbon chain lengths, physical and toxicological properties, and environmental impacts.

It includes long-chain PFAS such as PFOS and PFOA that are considered persistent, bio-accumulative, and toxic (PBT).

It also includes short-chain PFAS, such as C6 fluorotelomer fluorosurfactants used in current-day AFFF agents.

Short-chain (C6) fluorosurfactants do not contain or breakdown in the environment to PFOS or PFOA, and they’re currently considered lower in toxicity with significantly reduced bio-accumulative potential compared to long-chain PFAS.

Foams made with only short-chain fluorosurfactants likely contain trace quantities of PFOA and PFOA precursors as an unavoidable byproduct of the manufacturing process.

Advanced analytical methods and more sensitive instrumentation developed in the 1990s led to the detection of small amounts of PFAS chemicals, specifically PFOS and PFOA, in blood and the environment.

In response to getting this data, some manufacturers, like 3M, began phasing out PFOS and PFOA production in 2002.

In the early 2000s, government environmental agencies around the world intensified their scrutiny of PFAS chemicals, and over the past twenty years, many governments have passed legislation that restricts or bans the use of PFAS-based foams.

Because of these changes, many end users are transitioning or planning their transition to the next generation of fire protection.  

Making that transition, however, is a big decision for any company.

End users need to confirm compatibility between the next generation foam and existing hardware in the foam system.

A couple of key considerations include maintaining business continuity and minimizing the capital investment required to make the transition.

The final solution is almost always influenced by the Authority Having Jurisdiction (AHJ) approving the foam system – i.e., Fire Marshall, Municipal Fire Department, or Insurance company.

These organisations also must factor in third party approvals from Underwriter Laboratories (UL), Factory Mutual, EN 1568 standard and or other vertical market foam standards, including U.S. MIL-SPEC, International Civil Aviation Organisation (ICAO), International Maritime Organisation, or the U.S. Coast Guard. 

Foam systems are often in place for decades, and end users must make sure that their solution is sustainable for years to come. 

What to Consider When Moving to a New Foam System 

Class B foams are used to address the two primary types of fuel hazards – hydrocarbon and polar solvent.

Hydrocarbon fuels typically have a lower density than water and are not water miscible – i.e., gasoline, diesel, and aviation fuels.

Polar solvents include fuels such as ethanol, methanol, and isopropyl alcohol, which are miscible with water.

AFFF foams are used to create a foam blanket that readily spreads across the surface of the fuel separating the fuel source from the oxygen in the air and drainage of the foam blanket provides continual cooling to the surface of the fuel.

Alcohol resistant AFFF (AR-AFFF) firefighting foams have an additional feature that includes polymer(s) that are insoluble in the fuel.

These polymers precipitate out on the fuel surface and provide protection for the foam blanket from the polar solvent fuels that are hydrophilic (attracted to water).

This foam blanket separates the fuel from the oxygen in the air, suppressing the fire.  

Perimeter Solutions’ new SOLBERG® VERSAGARD™ AS-100, is a fluorine-free alcohol type concentrate (ATC™) proportioned at 3% for both hydrocarbon and polar solvent fuel fires.

This is a tremendous advantage for municipal and/or industrial firefighters because they don’t have to worry about whether the foam they are using is the right foam for the job. 

With all the focus on the use and regulations around PFAS based foams, there is little attention being paid to the inclusion of certain kinds of siloxanes in new fluorine-free solutions.

Some of these siloxanes are very persistent in the environment, and they are facing the same environmental pressures as fluorinated chemistries.

In fact, regulatory bodies including the Stockholm Convention for Persistent Organic Pollutants and California’s Prop 65 have already flagged certain siloxanes for their environmental persistence. 

Case Studies – Making the Move to Fluorine Free 

Perimeter Solutions is working with many customers to help them transition their fire safety systems. Each project is unique based on the customer, their industry and how old the system is that they are replacing. 

One of the more recent projects we completed was with the Lehigh Valley Airport Authority.

They were interested in updating the fluorinated foam system used in one of their 40,000 square foot hangars.

This is considered one of the largest hangar sizes and is a National Fire Protection Association 409 Group 1 hangar.

That means that it requires an aircraft access door height of more than 28’, it can house an aircraft with a tail height over 28’, and that it needs to have a single fire area in excess of 40,000 square feet.  

We helped the Airport Authority to convert its deluge fire sprinkler system, which was designed for 0.16 gallons per minute per square foot.

We were able to retrofit that existing system to use SOLBERG RE-HEALING™ foam 3%, fluorine-free 3%. This version of RE-HEALING foam has the exact same design application rate as the AFFF foam that they were previously using. 

By selecting a foam with the same design application rate, the customer didn’t need to change out its discharge devices, or the piping infrastructure, dramatically reducing the amount they needed to invest to upgrade.

It was simply a matter of bringing in new foam storage, a change in the proportioner, and a change in the foam.  

Another project recently completed involved the installation of a foam system at an 800,000 square-foot flammable liquid storage facility.

This was a racked storage facility that included a significant amount of flammable and combustible liquids on the property – both hydrocarbon and polar solvents. 

The facility needed to transition to a versatile foam that would allow them to extinguish fires regardless of the fuel source.

Based on its versatility, the customer decided to use VERSAGARD AS-100 and has had great success with the new foam. 

Fluorine Free Foam Technology- A Look Ahead 

Both of these transitions demonstrate that fluorine-free foams can now meet the needs of end-users who are looking for alternatives to legacy AFFF and AR-AFFF foams.

It will still be some time before AFFF and AR-AFF foams are completely replaced by fluorine-free alternatives, but we will see more of it in the next few years as regulations and requirements are updated.

In fact, the United States Federal Aviation Administration (FAA) recently issued a certification alert that removed a mandate to use fluorinated foams.

The FAA didn’t alter the existing performance specifications within the certification, so fluorine-free solutions must meet those specifications, but this shows that US agencies are creating inroads for fluorine-free technology. 

The U.S. MIL-SPEC is also expected to transition to fluorine-free foam, and the U.S. military has stated that it will no longer purchase and/or use fluorinated foams starting in 2024, except for shipboard for the navy.

For those of you that have been around since the early days of AFFF and AR-AFFF, you may recall that they were proportioned up to 9% foam concentrate. 

Through continued innovation, those percentages dropped to 3% and in some cases all the way down to 1%, meeting or exceeding the same level of effectiveness.

It is likely that fluorine-free foams will see the same type of development and will ultimately catch up to the legacy foams with the same proportioning percentage and application rates.

About the Author

Craig McDonnell is the General Manager at Fire Suppressions Americas, Perimeter Solutions profiles the history of fluorine-free Foam