Standard acrylic is not fire resistant. It ignites at temperatures between 260°C and 370°C (500°F to 700°F), burns slowly once lit, and releases toxic gases including carbon monoxide. While specialty fire-retardant acrylic sheets exist, the material in its common form is one of the more flammable transparent plastics on the market.
How Acrylic Behaves in a Fire
Acrylic, technically called polymethyl methacrylate (PMMA), starts softening at around 100°C (212°F). Above roughly 220°C, it begins to thermally decompose, breaking down at the molecular level. Actual ignition happens somewhere between 260°C and 370°C depending on the thickness, formulation, and how the heat is applied.
Once ignited, acrylic burns steadily and can produce flaming drips that spread fire to surfaces below. It also generates significant smoke. In testing of intumescent coatings containing acrylic resin, the acrylic component alone accounted for about 35% of all smoke produced during combustion, even though it made up a smaller fraction of the material by weight. The gases released during burning are poisonous, with carbon monoxide being the primary concern.
Acrylic vs. Polycarbonate for Fire Safety
If you’re choosing between acrylic and polycarbonate for an application where fire is a concern, polycarbonate is the safer option. Polycarbonate has low flammability and tends to self-extinguish, meaning it stops burning once the flame source is removed. Acrylic does the opposite: it continues to burn slowly and releases carbon monoxide as it does. For glazing, enclosures, or any installation near heat sources or open flames, polycarbonate is the standard recommendation over acrylic.
The tradeoff is that polycarbonate scratches more easily and typically costs more. Acrylic offers better optical clarity and UV resistance, which is why it remains popular for signage, aquariums, and display cases where fire exposure is unlikely.
Fire-Retardant Acrylic Sheets
Manufacturers do produce specialty acrylic sheets engineered for better fire performance. These contain additives that raise the ignition threshold and reduce how fast the material burns. Two well-known examples from the ACRYLITE brand illustrate what these products can achieve.
ACRYLITE Resist 45 has a self-ignition temperature of 950°F (510°C) and burns at just 0.7 inches per minute. ACRYLITE Resist 65 self-ignites at 842°F (450°C) and burns at 1.4 inches per minute. Both produce a smoke density rating of only 3.8%, which is exceptionally low. For comparison, building codes for light-transmitting plastics typically require a self-ignition temperature above 650°F, a smoke density below 75%, and a burn rate under 2.5 inches per minute. Both of these products clear those thresholds comfortably.
These fire-retardant sheets earn a CC2 classification, meaning they do still burn but at a controlled rate. A CC1 rating, the better of the two classes, requires the burn to stop within one inch of the flame source. Even the best fire-retardant acrylic doesn’t fully self-extinguish the way polycarbonate does, so calling it “fire resistant” would be an overstatement. It’s more accurate to say it’s fire-retardant: it resists ignition longer and burns more slowly, but it will still burn.
Where Fire Risk Matters Most
Building codes in most jurisdictions restrict where acrylic can be used based on its fire performance. Standard acrylic is generally prohibited in applications like skylights over exit corridors, interior wall panels in high-occupancy buildings, and anywhere building codes require a specific flame-spread rating. Fire-retardant grades expand where acrylic is permitted, but they still aren’t approved for all the same applications as glass or polycarbonate.
If you’re using acrylic in a home workshop, retail display, or picture frame, fire risk is minimal under normal conditions. But for greenhouse panels, light fixtures in commercial spaces, or any enclosure near heating elements, you should either choose fire-retardant acrylic specifically or switch to polycarbonate or tempered glass. The label matters: standard cast acrylic and fire-retardant acrylic look identical, so you need to verify the product specification before assuming it meets any fire code.