Regulators worldwide are phasing out PFAS because these “forever chemicals” persist in the environment and have been linked to health concerns. That has triggered product bans, litigation and a wholesale rethink of foam use in high-hazard facilities.
Many people assume the swap is as simple as emptying one tank and filling another, yet fixed systems that rely on positive displacement gear pumps were designed around aqueous film forming foam.
Dennis Convey
To achieve the same level of protection with synthetic fluorine-free foam, engineers must recalculate hydraulics, measure viscosity effects and often modify pumps, proportioners and discharge hardware. Retrofitting without that work risks slower knockdown and regulatory non-compliance.
AFFF quickly produces a vapour-sealing film that suppresses volatile fuel vapours. Fluorine-free foams cannot create that film, so their success depends entirely on blanket quality, expansion and stability. Knockdown times can be longer and performance on volatile fuels may drop unless the system is adjusted.
In practical terms, designers must focus on expansion ratio, water quality and the ability of the blanket to survive heat, wind and mechanical agitation. Those factors become critical in aviation hangars and bulk fuel storage where conditions are harsh and response time is tight.
Approved fluorine-free foams are usually non-Newtonian and shear-thinning, so you cannot rely on a single viscosity value. The entire shear curve dictates friction loss. Many concentrates are far thicker than AFFF, which calls for positive displacement pumps and new proportioners unless you have an FM approved electronic foam proportioner.
Expansion ratio depends on nozzle design as much as the liquid itself, while application rate can rise sharply on challenging fuels.
Dennis Convey
Selecting a concentrate means checking UL, FM or EN listings, reading application test results and matching the data to the site’s hazards rather than choosing on price or availability alone.
Proportioners, ILBP units and venturi devices may fail to hit accurate dosing with thicker liquids, so they often need replacing. Pressure sustaining valves must have materials and sensing lines sized for higher viscosity. Aspirating nozzles must be certified with the chosen concentrate. Centrifugal pumps struggle with the new friction profile; NFPA 20 now expects listed positive displacement pumps for all foams.
Replacing PFAS foam is unavoidable, but doing it on the cheap is expensive. Budget for proper engineering, choose UL and FM approved positive displacement pumps and insist on full-scale acceptance testing. With the right concentrate, correctly sized pumps and verified hydraulics, you will meet code, satisfy insurers and protect the environment.
Fire Lion Global can support that process with our electronic proportioners and listed pumps, all tested against leading fluorine-free concentrates. The result is a safer system that is ready for future standards rather than a retrofit you will have to revisit in two years.
