Most retardants fight fire once it has fuel, oxygen, and heat in equilibrium. AFT changes the equation upstream — interrupting all three legs of the fire triangle at the molecular level, without PFAS, halogens, or toxicity to the watershed downstream.
Every combustion event requires heat, fuel, and oxygen in continuous equilibrium. Conventional firefighting attacks the loop after ignition. AFT pre-loads the substrate so the loop never closes in the first place.
AFT's mineral salts decompose around 180–220°C, absorbing roughly 600 kJ/kg of energy as they break down. The substrate beneath stays below pyrolysis temperature even under direct flame impingement.
Acid-catalyzed dehydration strips water from the cellulose chain before it can crack into combustible volatiles. What's left is a stable carbon skeleton — char, not gas — and char doesn't feed flame propagation.
The same reaction releases non-combustible vapors (water vapor, CO₂, and inert ammonia derivatives) directly at the surface, displacing O₂ in the boundary layer and starving any nascent flame of oxidizer.
Slow-motion cone-calorimeter footage and SEM cross-sections of treated substrates reveal a layered defense forming before ignition would normally occur.
Cross-Section
Treated cellulose substrate after 90s @ 50 kW/m² heat flux
Phosphoric acid radicals catalyze dehydration of cellulose at 180–220°C, producing a 3–5 mm intumescent char layer with thermal conductivity around 0.1 W/m·K — equivalent to fiberglass batt insulation.
Hydrated mineral salts release bound water endothermically. Each kilogram of activated retardant consumes roughly 600 kJ of incident energy — equivalent to evaporating a quarter-liter of water per square meter.
Decomposition products — primarily H₂O vapor and CO₂ — vent at the surface and dilute the O₂ concentration in the boundary layer below the 14% lower flammability limit for most cellulosic fuels.
Halogen-free ammonium polyphosphate intermediates capture the OH• and H• radicals that propagate gas-phase combustion — terminating the chain reaction without introducing the brominated or chlorinated byproducts of legacy retardants.
Aqueous film-forming foams have suppressed jet-fuel fires for fifty years — and contaminated groundwater for the same fifty years. The 2024 EPA PFAS rule and DoD's fluorine-free transition mandate now make the comparison existential, not academic.
| Attribute | AFTFluorine-Free Retardant | LEGACYAFFF / Class B Foam |
|---|---|---|
| PFAS / Fluorosurfactants | None — fluorine-free formulation | Primary active ingredient (PFOA / PFOS class) |
| EPA UCMR-5 Reporting Limit | Non-detect | Exceeds groundwater health advisory by 100,000×+ |
| Half-life in Environment | Biodegrades within 28 days (OECD 301B) | Effectively infinite — 'forever chemicals' |
| Aquatic Toxicity (LC50) | >1,000 mg/L (practically non-toxic) | 1–10 mg/L range (moderately to highly toxic) |
| Use Restrictions (2025+) | Approved in all 50 states + EU | Banned or sunset in 13 US states, EU REACH restriction |
| Required PPE on Application | Standard hand protection | Full bunker gear + SCBA recommended |
| Class A Performance | ASTM E84 Class A on treated cellulose | Class B optimized — limited Class A efficacy |
Regulatory note for specifiers
Per EPA's April 2024 final rule, public water systems must monitor for PFOA and PFOS at 4 ng/L MCL beginning 2027 with compliance by 2029. Sites with documented AFFF discharge are presumed contributors. AFT carries no PFAS in formulation, in degradation products, or as manufacturing-process impurities — verified by independent LC/MS/MS to detection limits below 2 ng/L.
Wildfire suppression in the wildland-urban interface inevitably reaches streams, retention ponds, and aquifers. AFT was engineered to be measured against the strictest aquatic-safety benchmarks the EPA maintains — and to pass them by an order of magnitude.
Side-by-side burn test
Identical 2×4 pine boards, identical propane torch exposure for 60 seconds. The treated board shows surface charring with structural integrity intact; the untreated board has ignited and is propagating flame independently.
Lab data from the same test methods your code official is going to ask for: ASTM E84 for finished surfaces, ISO 5660 cone calorimetry for heat-release rate, and NFPA 701 for textiles.
Surface Temperature
Pine substrate, 50 kW/m² heat flux
ISO 5660 cone calorimeter
Flame Spread Index
Lower is better — Class A ≤ 25
ASTM E84-23a
ASTM E84 Class A
FSI 15 / SDI 25
Flame Spread Index of 15 and Smoke Developed Index of 25 — well inside the Class A envelope of FSI ≤ 25 / SDI ≤ 450.
NFPA 701 (textile)
Pass — both methods
Treated curtain and drape samples pass both Test Method 1 (small scale) and Test Method 2 (large scale, >21 oz/yd² fabrics).
FAR 25.853(a) / 60-sec
Vertical burn pass
Qualified for cabin-interior application on commercial & private aviation — the standard that governs Air Force One textiles and Gulfstream / Lear interiors.
Each technology was engineered for a different problem. The honest answer about when to use what.
| Criterion | AFT Fire Defense Coating | FOAM Class A Wetting Foam | PAINT Intumescent Paint |
|---|---|---|---|
| Primary code reference | ASTM E84 surface burning | NFPA 18A / 1145 wildland | UL 263 / ASTM E119 structural rating |
| Application stage | Pre-treatment, weeks to years before any event | Active suppression during the event | Pre-treatment, structural design phase |
| Durability after cure | Internal: indefinite. Exterior: 2-year retreat cycle | Single-use — drains/evaporates within hours | 10–20 yr service life with topcoat |
| Aesthetic impact | Invisible — clear, non-film-forming | Visible foam blanket (operational only) | 1–3 mm dry film thickness, paintable |
| Substrate compatibility | Wood, textiles, paper, cellulose composites | Surface-applied to vegetation, structures | Steel, concrete, sometimes wood |
| PFAS / halogen content | None | Varies by formulation; many still contain PFAS | Most contain brominated flame retardants |
| Best fit | Interior finishes, wildland-urban defense, textiles | Active wildland firefighting operations | Structural steel columns & beams |
The same fluorine-free salt chemistry shows up as a soak-in inhibitor, a clear coating, a fire-water additive, and a homeowner-ready perimeter kit — sized for the application instead of the warehouse.
| Compare | Fire PreventionFire Inhibitor | Fire PreventionDefense Coating 2.0 | Fire PreventionDefense Coating 3.0 | Fire SuppressionWetting Agent | Application SystemsHome Protection |
|---|---|---|---|---|---|
| Use Case | Non-toxic, eco-friendly fire prevention treatment for porous materials | Multi-use invisible fire-resistant intumescent coating applied as paint | Multi-use invisible fire-resistant intumescent coating applied as paint | Eco-friendly, water-based fire suppressant for Class A, B, D, F, and K fires | Easy-to-apply DIY fire protection system — AFT Home Protection Solution |
| Stage | Prevention | Prevention | Prevention | Suppression | System |
| Coverage | 1 gallon covers approximately 300 sq ft of flat surfaces and 150 sq ft of irregular surfaces such as dense vegetation | ~250 sq ft per gallon | 53 SF/gallon | Mix 1:100 with water | 1 gallon covers approximately 300 sq ft of flat surfaces and 150 sq ft of irregular surfaces such as dense vegetation |
| Packaging | 1 gal, 5 gal pail, 55 gal drum | 1 gal, 5 gal pail | 5 gal pail, 55 gal drum, 275 gal tote | 5 gal pail, 55 gal drum, 275 gal tote | 5 gal pail, 55 gal drum, 275 gallon tote |
| Key Certification | ASTM E-84 | ASTM E84 CLASS A RATED | ASTM E84 Class A and ASTM E2768 Class A (30-min extended) | ASTM E84 CLASS A RATED | UL GREENGUARD Gold, ASTM E84 |
| Non-Toxic / Eco | |||||
| DIY-Applicable | |||||
| Best For | Treating interior wood, textiles & soft goods before a fire event | Long-term structural protection without altering aesthetics | Long-term maximum structural protection without altering aesthetics | Active firefighting across Class A/B/D/F/K scenarios | Homeowners defending property against wildfire threat |
Everything an AHJ, an underwriter, or a procurement officer is going to ask for — already packaged and waiting in the downloads vault.
The questions we get from fire marshals, code consultants, and underwriters on every project. No marketing handwaving — just the data, the test method, and what it actually proves.
AFT works through three simultaneous mechanisms. First, when heat reaches the treated surface, the mineral salts in the formulation undergo endothermic decomposition — they absorb roughly 600 kJ/kg of energy as they break down, cooling the substrate. Second, that decomposition forces the cellulose to char rather than pyrolyze into combustible gases, building an insulating carbon layer. Third, the reaction releases non-combustible vapors (primarily water and CO₂) that displace oxygen at the flame front. No single mechanism is sufficient alone; it is the combined effect that takes treated material below the ignition threshold.
Legacy aqueous film-forming foams (AFFF) rely on per- and polyfluoroalkyl substances — the 'forever chemicals' now regulated under EPA UCMR-5, the 2024 PFAS National Primary Drinking Water Regulation, and state-level bans in Washington, California, New York, Colorado, Maine and ten others. AFT contains zero intentionally added PFAS, zero fluorosurfactants, and zero halogenated flame retardants. For specifiers, that means no extended-producer-responsibility liability, no groundwater remediation exposure, and continuing eligibility for federal contracts under DoD's 2024 fluorine-free transition mandate.
LC50 is the concentration at which 50% of test organisms die over a 96-hour exposure. The OECD scale classifies anything above 100 mg/L as 'practically non-toxic.' AFT's formulations were tested against the standard EPA indicator species — Daphnia magna (water flea) and Oncorhynchus mykiss (rainbow trout) — and exceeded 1,000 mg/L in both cases. For comparison, legacy AFFF concentrates typically fall in the 1–10 mg/L 'highly toxic' bracket. Practically: AFT runoff entering a stream from a wildfire suppression event does not trigger a fish kill or NPDES reporting obligation.
Intumescent paints swell to roughly 50× their applied thickness when heated, creating an insulating foam over steel — they are the right choice for structural columns where you need a 1- to 3-hour fire-resistance rating per UL 263 / ASTM E119. AFT's Fire Defense Coating is a surface-burning treatment optimized for ASTM E84 (the tunnel test), which governs flame spread on interior finishes. They solve different code requirements. On combustible substrates like timber-frame, cross-laminated timber, or textile interiors, AFT is the correct intervention; on exposed structural steel, you still need an intumescent or a cementitious. The two systems are complementary, not redundant.
Untreated cellulose pyrolyzes between 300–400°C and releases levoglucosan and other volatile combustible gases — those gases are what actually burn in the gas phase above the wood surface. AFT shifts the pyrolysis pathway through acid-catalyzed dehydration: the mineral salts release phosphoric and sulfuric acid radicals at lower temperatures (180–220°C), which strip water from the cellulose chain before it can crack into combustible volatiles. The leftover carbon backbone forms a 3–5 mm intumescent char with a thermal conductivity of ~0.1 W/m·K — roughly the same as fiberglass batt insulation — protecting the substrate beneath.
All third-party test reports (UL Solutions, FM Approvals, Intertek), the GREENGUARD Gold certificate, NFPA 701 textile burn data, FAR 25.853 aviation interior certification, EN 13823 European Single Burning Item results, and current SDS sheets are available in our Downloads section. Sales-engineering can also provide project-specific submittal packages for AHJ review on request — typically returned within two business days.
Whether you're specifying interior finishes for a high-rise, drafting an NFPA 1145 plan, or hardening a wildland-urban interface community, our fire engineers will return a project-specific submittal packet within two business days.
