Bathtub Chemistry

By Jim Sery, President, AF3, Inc.

“Bathtub chemistry”. When I was an R&D chemist at National Foam, that is what I jokingly called the “science” behind some startup companies’ new products. Their demonstrations were tailored to put out fires and impress the audience, but their shows didn’t represent real-world fires. A fuel that is easy to extinguish was chosen. There was no pre-burn time that increased the fuel and fire temperature as in a real incident. The application rate and foam concentration were set higher than was commercially viable. There was no Burnback resistance and the tests avoided that aspect. When I subjected their miracle foam to actual fire conditions, they all failed.

When I founded AF3, and began developing firefighting foam products on my own, I built my laboratory in my garage. And yes, it was complete with an old blue bathtub that I used for running foam tests. It was then that I fully understood the challenges of the “bathtub chemist”. How can one introduce groundbreaking innovations with limited funds in an industry that is protective of its market and fearful of new technology and competition? My guiding principle was the UL 162 fire testing standard. I knew that if I formulated my products to exceed these rigorous tests, they would succeed, no matter how humble their beginnings.


There was another problem that I foresaw that would not make headlines for several years. I knew that fluorochemicals in firefighting foam were a necessary evil required to protect life and property. But these chemicals stay in the environment for centuries, were found in humans' blood and later would be linked to cancer and other diseases. I made it my life’s goal to make firefighting foam as clean and safe as water.  

The Process – Eureka!

Fortunately, the first year in my outdoor garage-lab was the second warmest winter on record for the area. Temperatures rarely dropped below 50 degrees F, which is the minimum fuel temperature for the UL 162 test, and perfect for my outdoor fire testing. I was experimenting with a fluorine-free foam technology I developed. It was an additive that stabilized any foam so well that it performed like the fluorochemical foams called “AFFF” (Aqueous Film Forming Foam) and “AR-AFFF” (Alcohol Resistant Aqueous Film Forming Foam). Several fire tests failed which is always disheartening. The UL test is purposefully challenging:  a one-minute pre-burn to heat the fuel and walls of the test pan, use of sea water to stress the limitations of the foam and burn-back testing to simulate disruption and ignition of the aged foam blanket . But with each failure, you learn the weaknesses of that formulation and adjust to maximize its strengths. After persistence in the lab, one formulation astounded me.

At 0.10 gpm/sq.ft. in sea water, the foam shot across the burning acetone with the speed and extinguishment only seen with fluorine-rich foams. But my new formulation had zero fluorine. It also used a simple Class A foamer. Wait – did a Class A foam just extinguish an acetone fire? Doesn’t Class A foam dissolve on contact with a polar solvent like acetone? Torch tests throughout the length of the test showed no fuel pickup into the foam. Cutting a hole in the foam and igniting for burnback was self-extinguishing - for over an hour! Current products on the market only last minutes. Subsequent tests proved that this additive could turn any Class A foam into an Alcohol Resistant AFFFwith zero fluorine. This was the breakthrough I was looking for. “A-zero-F®” was born.

A-zero-F® – The Science Behind the Product

With invaluable help from our dedicated team, we patented A-zero-F®, a sugar-based polymer that turns any inexpensive Class A foam, or even a simple dishwashing liquid, into an AR-AFFF without the use of hazardous fluorochemicals. If this is sounding like some of the outlandish products I used to dismiss years ago, let me explain the science behind the claims.


With current firefighting foam technology, 0.045% is the maximum amount of the key ingredient in an AR-AFFF that can be delivered to a fire.  It is too viscous for any more to dissolve or “fit” in the foam concentrate in the pail. This powerful foam stabilizing polymer keeps firefighting foam from dissolving into polar solvent fuels. It is what keeps the bubbles stable against hydrocarbon infiltration and keeps the aged foam from igniting in flashovers. But since it is limited to only 0.045% of the foam, it needs help from fluorine. Hazardous fluorochemicals work well on fires but there is a trade-off in human health and environmental sustainability.  Fluorochemicals from firefighting foams have contaminated drinking water and are linked to cancer and other diseases.  The firefighting foam industry has sidestepped this dangerous threat by switching to another type of fluorochemical which shortens the hazardous molecule by two atoms. I sincerely hope that ten years from now it is confirmed that this was indeed a safe alternative. A preferred alternative would be if we could deliver more than 0.045% of an environmentally friendly polymer to the fire. If so, fluorine could be eliminated.

To achieve this, we need to think outside of the pail...

A-zero-F® is a specially designed environmentally friendly foam stabilizer that can be added directly to the water source or can be educted like a standard foam. Both methods remove the limiting constraints of the pail. Firefighting power is increased 10 times over current AR-AFFF and AFFF foams. It also removes the need for fluorine, its hazards and the bulk of the cost. A simple Class A foam will now work on any type of fuel fire with no need to match the foam to the fuel. “One additive, any foam, any fuel™.”

The foam can last more than four days (96-hour Quarter Drain Time - time it takes ¼ of the water to drain from the foam) using standard off-the-shelf equipment and AF3’s Class A foam, FoamLife Max™. Using A-zero-F with a standard Class A foam and a non-aspirated fog nozzle produces 2-hour Quarter Drain Times compared with 2 minutes without A-zero-F. This gives superior firefighting performance at long ranges with low energy nozzles and low expansion fast spreading on hydrocarbon fires. This means longer burnback resistance than AFFFs and AR-AFFFs, super-long foam duration for firebreaks, no re-application required for spill and vapor suppression on hot surfaces and superior extinguishment and burnback on large depth polar and hydrocarbon fires.

Formulated for the Future

I have since traded in the bathtub and garage for stainless steel reactors in a state-of-the-art manufacturing plant in Bear, Delaware. I often remember the early days shooting foam in the tub in balmy January weather, and not being able to contain my excitement about the number of days the foam was lasting without draining any of its water. I knew this was going to be the future of firefighting. But it was a different approach to fighting fires and, even though it was cheaper, cleaner and more powerful than any product on the market, I knew it would take time, investment and education to prove its advantages.


The ultimate advantage is an effective life-saving foam that is safe for humans and the environment. In my demos, I actually drink A-zero-F. It tastes like what I would imagine dilute wallpaper paste would taste like. I proved that firefighting foam can be as clean and safe (though not as tasty) as water. The hard part has now begun – education will be needed to bring this technology to market. Help AF3 get there by considering the benefits of thinking outside of the pail.