Quick answer: A Class A fire rated acoustic panel has a flame spread index (FSI) of 0–25 and a smoke developed index (SDI) of 450 or less when tested to ASTM E84, the best of the three ASTM E84 classes. Our PET acoustic panel was tested by SGS to ASTM E84 with FSI 15 and SDI 25, and is also classified B-s1,d0 to the European standard EN 13501-1.
ASTM E84 (also published as UL 723) is the North American tunnel test for the surface burning characteristics of building materials. A sample about 7.3m long is mounted on the ceiling of a tunnel and exposed to a gas flame for 10 minutes. Two numbers come out of the test:
Flame spread index (FSI): how fast flame travels along the surface, compared with reference materials.
Smoke developed index (SDI): how much smoke the material gives off while burning.
Building codes in the United States and Canada group the results into three classes:
| Class | Flame spread index | Smoke developed index |
|---|---|---|
| Class A (Class I) | 0–25 | 450 or less |
| Class B (Class II) | 26–75 | 450 or less |
| Class C (Class III) | 76–200 | 450 or less |
Class A is the classification most often required for wall and ceiling finishes in exits, corridors, schools, offices and other public interiors, which is why buyers ask for it first.
| Standard | ASTM E84-24 |
| Laboratory | SGS |
| Report number | SDFTS25004023R02_EN (issued 21 July 2025) |
| Sample | Jiadian PET acoustic panel, 12mm |
| Flame spread index | 15 |
| Smoke developed index | 25 |
| Classification | Class A |
An FSI of 15 sits well inside the 0–25 Class A range, and an SDI of 25 is far below the 450 limit. You can verify the report number at check.sgsonline.com.cn. See all our reports on the PET acoustic panel test reports page.
The two standards use different test methods, so one cannot be converted into the other. Use the one your project market asks for:
| ASTM E84 | EN 13501-1 | |
|---|---|---|
| Used in | USA, Canada and many projects that follow US codes | EU, UK and many projects that follow European codes |
| Test method | Tunnel test, flame spread and smoke | SBI test (EN 13823) and small flame test (EN ISO 11925-2) |
| Best result for PET panels | Class A | B-s1,d0 |
| Our result | Class A (FSI 15, SDI 25) | B-s1,d0 |
EN 13501-1 gives three parts in one classification:
B is the reaction to fire class. Classes run from A1 and A2 (non-combustible materials such as stone and mineral wool) through B, C, D, E and F. B is the best class an organic material like polyester fiber can normally reach.
s1 is the lowest smoke production class (s1, s2, s3).
d0 means no flaming droplets or particles during the test (d0, d1, d2).
Our EN 13501-1:2018 classification (SGS report SDFTS25004023R01_EN, 12mm sample, 2.40kg/m²) recorded FIGRA 25.2 W/s, THR600s 2.0 MJ and TSP600s 14.2 m², with no flaming droplets.
Not every PET acoustic felt on the market is fire rated. Fire-retardant felt costs more to make and test, so a much cheaper quote may be for standard, non-fire-rated felt. When you compare suppliers, ask:
Is the quoted panel the fire-retardant version?
Which standard was it tested to, and which class did it reach?
Can you share the report number so I can verify it with the lab?
Which thickness and density was tested?
Our PET acoustic panel price guide explains how fire-retardant performance and other factors affect price.
Use precise terms such as fire rated, ASTM E84 Class A or classified EN 13501-1 B-s1,d0. Avoid fireproof or non-combustible: polyester fiber is a combustible material that has been tested and classified, and accurate wording helps your submittal pass review.
Our 9mm, 12mm and 24mm PET acoustic panels come in 1220 × 2440mm sheets in about 90 standard colors, with 9mm and 12mm kept in stock. Custom shapes are available through CNC cutting and grooving and 3D molding.
Enter the report number at check.sgsonline.com.cn, or contact us for the full report and free A4 samples.
Sourcing PET acoustic panels from China? Learn how to compare panel quality, density, fire ratings, colors, customization, MOQ and supplier reliability.
Jiadian is a direct PET acoustic panel manufacturer in Changshu, China, founded in 2013, with its own production lines and 8000 sqm daily capacity.
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