ASTM E84 Class A for Fume Hood Liners, Explained

ASTM E84 is the test most fume hood and building specifications use to rate how interior surface materials burn. If you are selecting or qualifying a fume hood liner, the E84 flame spread index is usually the first fire-performance number your customers will ask for. Here is how the test works and how to read the results.

 

What ASTM E84 Measures

ASTM E84, Standard Test Method for Surface Burning Characteristics of Building Materials, is often called the tunnel test; UL 723 is the equivalent UL standard. A sample about 24 feet long is mounted on the ceiling of a horizontal tunnel and exposed to a gas flame at one end for 10 minutes. The test records how far and how fast flame travels along the surface, and how much smoke the burning material produces.

 

Flame Spread Index and Fire Classes

Results are reported as a flame spread index on a scale where inorganic reinforced cement board is 0 and red oak flooring is 100. Building codes group materials into three classes:

• Class A (Class I): flame spread 0 to 25

• Class B (Class II): flame spread 26 to 75

• Class C (Class III): flame spread 76 to 200

The lower the number, the more slowly flame travels across the surface.

 

Smoke Developed Index

The same test measures the smoke a material gives off, reported as the smoke developed index. Building codes generally require a smoke developed index of 450 or less for interior finish materials, in addition to the flame spread class.

 

What Fume Hood Liner Specifications Require

Most laboratory fume hood specifications call for liner materials with a flame spread index of 25 or less, the Class A range. Because fume hoods handle flammable solvents and are installed in occupied labs, specifiers generally treat Class A as the minimum for liner panels, baffles and side walls.

 

How CS1000 Performs

• Flame spread index: 15 (Class A)

• Smoke developed index: 250, below the common 450 limit

• Test laboratory: QAI Laboratories, August 2025

• Also: UL 94 V-0 rated and UL Listed (UL File No. E550115)

See the full CS1000 test results for SEFA 3 chemical-resistance and mechanical data, or compare CS1000 with other fume hood liner materials.

 

E84 Is Not the Only Fire Test

ASTM E84 rates surface flame spread on a large sample. UL 94 is a separate small-scale test that rates how a plastic material stops burning once the flame is removed; V-0 is the best of its vertical-burn ratings. Ask your liner supplier for both results, along with the test laboratory and date, so you can confirm they apply to the material you are buying.

 

Questions about fire ratings for your hood line? Contact us for the full CS1000 ASTM E84 report or samples.