ASTM E84 Testing

The ASTM E84 test assesses a building material's surface burning characteristics. The test rates a building material's contribution to flame spread and smoke development. Building and interior finishing materials must undergo this process for use in construction. While wall and ceiling materials are frequent specimens, this test also applies to elements like paints, sealants, coatings, adhesives, insulation and textiles.

Standard Test Method for Flammability of Building Materials

The 2021 International Building Code (IBC) requires building materials to undergo ASTM E84 testing and receive Flame Spread Index (FSI) and Smoke-Developed Index (SDI) ratings. The FSI measures how fast the flame spreads, while the SDI reflects how much smoke the sample produces during the test's time constraints based on optical density measured by a light obscuration meter. These results report how the specimen's surface behaves when exposed to fire conditions and certify whether a tested material is suitable for the intended application.

The test assigns a rating based on the specimen's FSI and SDI. These standards are:

• Class A: The building material has an FSI between 0 and 25.
• Class B: The specimen's FSI is between 26 and 75.
• Class C: The material's FSI is between 76 and 100.

The tested building material must have an SDI between 0 and 450 to qualify for any class rating.

About the Steiner Tunnel Test

The Steiner Tunnel Test has been North America's standard method for ASTM E84 testing since the mid-1940s. Laboratories use the Steiner Tunnel for additional materials testing applications, such as meeting criteria set by the Underwriters' Laboratory (UL) and National Fire Protection Association (NFPA).

This noncombustible apparatus is equipped with two burners, and each resulting flame has an 89-kilowatt intensity. The tunnel is 24 feet long and 1.8 feet wide and features a removable top lid. During the test, the air moves through the tunnel at 240 feet per minute, and the flame spread and smoke developed are observed through viewing windows.