Short answer: Yes. Acrylic is a combustible plastic: it self-ignites at about 750 to 910 °F (ASTM D1929) but lights readily from a flame, and once burning it keeps going; Acrylite says it usually burns rapidly to completion if not extinguished. Standard sheet is rated UL 94 HB (horizontal burn, not self-extinguishing) and burns at about 1.0 to 1.2 in. per minute in ASTM D635, which qualifies common cast sheet such as Plexiglas G and Acrylite for building code class CC2; check your local code before using it in a building.
How does acrylic burn?
Acrylic is made of carbon, hydrogen, and oxygen, and it behaves like a dense, steady fuel:
- It needs real heat to self-ignite, but a flame lights it. Self-ignition temperatures (ASTM D1929) are 750 °F for Optix, 850 °F for Acrylite extruded, 860 °F for Plexiglas G, and 910 °F for Acrylite cast. The Plexiglas fabrication manual notes its ignition temperature is higher than most woods, yet it "will ignite readily."
- It burns vigorously once going. Acrylite: it "usually burns rapidly to completion if not extinguished." It doesn't put itself out.
- Combustion products: with plenty of air, mostly carbon dioxide and water; in a real fire with limited air, toxic carbon monoxide too, as with other combustibles (Acrylite).
- It softens and drips. Burning acrylic melts and can drip flaming material onto whatever is below.
Key facts
- UL 94: HB for Plexiglas G (0.060 in. and thicker) and Optix-L.
- Horizontal burn rate (ASTM D635, about 1/8 in.): Acrylite cast 1.2 in./min; Acrylite extruded 1.0; Optix 1.18; Plexiglas G under 1.0.
- Building code class (IBC 2606.4): Plexiglas G CC2 (0.118 to 0.944 in.); Acrylite cast CC2.
- Smoke density (ASTM D2843): 1.0% Plexiglas G, 4.8% Acrylite extruded, 11.4% Acrylite cast, 13.5% Optix.
- Surface burning: Optix-L flame spread 110 and smoke developed 530 (ASTM E84); Plexiglas G flame spread 135 (CAN/ULC-S102.2).
- Europe: Röhm PLEXIGLAS is DIN 4102 class B2 and EN 13501 class E (normal flammability).
What do CC1 and CC2 mean?
The International Building Code (section 2606.4) sorts light-transmitting plastics using the ASTM D635 burn test at 0.060 in. or the thickness intended for use:
- CC1: burning extent of 1 in. or less.
- CC2: burning rate of 2 1/2 in. per minute or less.
Both classes also require a self-ignition temperature of at least 650 °F and a smoke-developed index no higher than 450 (ASTM E84) or a smoke density rating no higher than 75 (ASTM D2843). Standard acrylic, burning at about 1 in. per minute, lands in CC2. The class matters because the code sets different limits for each, for example on skylight and roof-panel areas, and limits plastic glazing in walls. Codes vary by edition and jurisdiction, so check your local code or ask your building inspector or fire marshal. This is general material information, not legal advice.
Is acrylic self-extinguishing?
No. UL 94 HB only means a horizontal sample burns slowly enough to pass that test; self-extinguishing materials earn V-0, V-1, or V-2 ratings in the vertical test. Standard acrylic sheet doesn't. Fire-retardant acrylic grades exist for special uses, but standard sign and display sheet isn't one of them.
How does acrylic compare with polycarbonate and glass in a fire?
| Material | Fire behavior (general) |
|---|---|
| Acrylic | Combustible, burns steadily, drips, doesn't self-extinguish; typically UL 94 HB and code class CC2 |
| Polycarbonate | Tends to char and self-extinguish when the flame is removed, and often carries better flammability ratings than acrylic. Check the product data. |
| Glass | Doesn't burn. Ordinary glass can crack from heat; fire-rated glass is a separate product. |
If fire behavior drives your material choice, polycarbonate or glass often makes more sense. Acrylic vs polycarbonate and acrylic vs glass.
Where shouldn't you put acrylic?
- Close to space heaters, wood stoves, fireplaces, grills, or open flames. Radiant heat softens it long before it lights.
- As a fireplace screen or stove guard. Use tempered or ceramic glass made for the job.
- Close to hot incandescent or halogen bulbs; Acrylite says to ventilate fixtures so heat can escape. LED fixtures are generally fine.
- Near candles, especially as a candle holder or lantern wall, unless the flame is kept well away and never left unattended.
Acrylic's continuous service limit is about 160 to 180 °F, and it deflects under load at about 195 to 210 °F, so heat damage normally comes long before fire. See acrylic heat resistance.
Is it safe to laser cut acrylic?
Lasers cut acrylic by vaporizing it, and a small flame at the cut point is normal. The Plexiglas manual specifically warns to take precautions during laser cutting and flame polishing so the sheet doesn't ignite. Laser cutting acrylic is routine but should always be supervised with good extraction and air assist, never left running unattended. Fumes are covered in are laser-cut acrylic fumes toxic.
How do you put out burning acrylic?
Treat it like any fire: get people out first. Small fires can be put out with a standard ABC extinguisher or water. Don't try to carry a burning piece; it drips. Call emergency services for anything you can't put out immediately.
Need parts for a project with fire requirements?
Tell us what your inspector or spec requires and we'll tell you honestly whether standard acrylic fits. For signs, displays, and covers away from heat, it's an excellent material: get an instant quote.
Questions
Can I use acrylic for an indoor business sign?
Acrylic signs are extremely common indoors. The 2015 IBC, for example, limits interior plastic signs to 20% of the wall area and 24 sq. ft. each, and local rules vary, so check with your building department for anything large or in a public space.
Is Plexiglas flammable?
Plexiglas is a brand of acrylic, so yes. Plexiglas G is rated UL 94 HB and building code class CC2, with a self-ignition temperature of 860 °F.
Is burning acrylic toxic?
The Plexiglas manual says burning acrylic doesn't produce smoke or gases more toxic than burning wood or paper, but any fire makes carbon monoxide and irritating gases. Don't breathe it, and ventilate or leave the area.
Is acrylic fire resistant or fireproof?
Neither. It's combustible and classed as slow-burning (UL 94 HB, CC2), not fire-rated. For fire-rated openings you need tested fire-rated glazing.
Sources
- Röhm/Polyvantis: ACRYLITE cell cast sheet (GP) technical information
- Röhm/Polyvantis: ACRYLITE premium (FF) technical information
- Plaskolite: OPTIX-L continuous cast acrylic sheet fabrication guide (typical properties)
- UpCodes: International Building Code 2015 (Virginia), chapter 26, plastic
- Röhm: PLEXIGLAS GS/XT technical information 211-1