Since the 1960s, airports have depended on aqueous film-forming foam (AFFF) when battling fires on airport grounds.
Whether the hazard involved crash rescue, hangar, or bulk fuel fires, AFFF foam has been a critical resource for airport fire brigades in containing and extinguishing these hazards.
However, in September 2023, the first fluorine-free foam concentrate was added to the U.S. Department of Defense Qualified Products List (QPL).
This addition allowed airport authorities and other government agencies required to use MIL-SPEC-qualified products to switch from fluorinated AFFF foams to a fluorine-free solution that meets industry standards for fast knockdown and extinguishment of gasoline and Jet A fuel spill fires.
Over the past year, dozens have completed the transition.
Fire protection at airports has been a critical concern since College Park Airport opened in Prince George’s County, Maryland, in 1909.
While firefighting foam was first invented in 1902, early versions were difficult to mix, use and transport.
The first effective firefighting foams were developed in the 1930s using a protein-based concentrate.
Protein foams had some inherent drawbacks – limited shelf life, limited storage temperatures, and they created an inconsistent end product due to the use of protein as the source and hydrolyzation.
Their range was limited based on the type of discharge equipment used.
It was the best option available, however, and remained the standard for the next 60 years.
The first AFFF solution was introduced in 1963 and was widely adopted for firefighting.
AFFF introduced multiple advantages over previous foams.
It had the ability to readily spread over a fuel surface, could be discharged through all types of nozzles, had an extended shelf life—and most importantly—it gave firefighters at all skill levels the greatest likelihood to suppress and extinguish a fire.
The foam was so effective, it remained the workhorse of the industry for decades.
In the early 2000s, the dominance of AFFF started to be threatened due to concerns over the use of per- and polyfluoroalkyl substances (PFAS) and perfluorooctanoic acid (PFOA), marking the beginning of the transition to synthetic fluorine-free foams (SFFF), or fluorine-free foams (F3), which contain no fluorosurfactants or fluoropolymers.
The switch to F3 was slow at first, as there was nothing to encourage airports or other entities to transition from AFFF.
There were no regulations against the use of AFFF, and early versions of F3 couldn’t match the effectiveness of AFFF.
That all changed in 2006 when the U.S. Environmental Protection Agency introduced the 2010/2015 PFOA Stewardship Program.
This new initiative called for a 95% decrease in the use of PFAS/PFOA by 2010 and for the complete elimination of its use by 2015.
The goal to reduce the use of PFAS/PFOA wasn’t met by the target date of 2015.
Those involved in fire safety still preferred to use AFFF, but the industry continued to advance F3 technology to make them just as effective as their AFFF predecessors.
These advancements led the National Fire Protection Association to recognize F3 as the future of the industry in safety standard NFPA 11, Standard for Low, Medium and High-Expansion Foam.
F3 is also used by the U.S. government and more extensively by fire management agencies outside the United States.
For effective fire protection at an airport, diverse solutions are needed to address the wide range of hazards that firefighters encounter.
Aircraft are often kept in hangars for repairs or protection from the elements, where they may be surrounded by flammable materials or liquids.
In these situations, using foam concentrates that are UL- or FM-approved for use with sprinkler heads and trench nozzles is critical.
F3 options have been effectively battling hangar fires for a long time, offering a reliable and more environmentally friendly solution.
Fuel storage tanks present another unique challenge and are arguably one of the largest fire hazards facing airport fire safety personnel.
A fire in a bulk fuel storage tank could potentially disrupt airport operations and global air travel significantly.
Such an incident could lead to airport shutdowns, causing grounded flights, diverted incoming flights, and widespread delays, resulting in millions of dollars in losses for the industry.
Fluorine-free solutions have been available for this type of fire for several years.
It is recommended to use products that can quickly suppress the fire while providing a slow-draining foam blanket.
F3 products meet UL and FM standards, and have also successfully passed LASTFIRE test standards, providing an additional level of confidence in the transition to fluorine-free solutions.
An aircraft crash is one of the most dangerous fire events that could take place at an airport, and it is the only fire hazard that is regulated by the U.S Federal Aviation Administration (FAA).
Until recently, F3 could not be used to battle these types of hazards.
However, in 2020, Congress set a requirement that the Secretary of the Navy must publish a new specification by January 2023 to initiate the replacement of AFFF with F3 solutions.
That new specification was introduced as MIL-PRF-3275 (I1), Fire Extinguishing Agent, Fluorine-Free Foam (F3) Liquid Concentrate, for Land-Based, Fresh Water Applications.
Before an airport could make the transition to F3 technology, however, a solution had to be tested to demonstrated it could meet the criteria of the new specification, so that it could be added to the U.S.
Department of Defense Qualified Products List (QPL).
SOLBERG® 3% MIL-SPEC SFFF was the first fluorine-free foam concentrate added to the QPL in September 2023.
The new solution successfully completed a total of nine different fire tests using both ethanol-free gasoline and Jet A fuel.
In addition to those fire tests, more than 20 different physical/chemical properties were analyzed before and after aging to ensure that the product would remain stable over time.
The foam concentrate was also tested for compatibility with dry chemical and for environmental impact.
This included acute aquatic toxicity as well as biological and chemical oxygen demand.
After the SFFF concentrate was added to the QPL, airports around the U.S. quickly started making the switch from AFFF.
There was greater demand after the new solution became the first on the QPL to be GreenScreen Certified Silver®, a third-party certification that verifies the foam does not contain intentionally added PFAS as well as more than 2,000 other chemicals of concern.
To spur an even quicker transition to F3 solutions, the new Clean Airport Agenda signed into law in the United States earlier this year, offers airports up to $2 million in reimbursement for the purchase of fluorine-free foams, related equipment, and clean-up expenses.
To ensure a smooth transition to F3 solutions, comprehensive training for fire safety personnel is essential.
This training should include hands-on experience with liquid fuel fires, as the performance of new F3 products differs from that of traditional AFFF solutions.
By equipping firefighters with the necessary skills and knowledge, airports can enhance their readiness to effectively combat aircraft crash scenarios and other fire hazards, ensuring the safety of both passengers and personnel.
Mark Siem is Business Development-Industrial/Chemist at Perimeter Solutions, which offers fluorine-free foam solutions airport firefighting, including crash rescue, sprinkler and underwing protection of hangars and bank fuel storage. Learn more at www.perimeter-solutions.com.
