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FAQ about ASTM E84


ASTM E 84: standard test method for surface burning characteristics of building materials

The purpose of ASTM E84 test is to observe the flame spread along with a sample in order to determine the relative burning behavior of its material. Through the E84 test, both the Flame Spread Index (FSI) and Smoke Developed Index (SDI) are reported for a given sample. FSI is the measurement for the speed at which flames progress across the interior surface of a building, while SDI measures the amount of smoke a sample emits as it burns.

1. When is the E84 test required?

The 2006 International Building Code (IBC) specifies that “interior wall and ceiling finishes shall be classified in accordance with ASTM E84.” Additionally, the National Fire Protection Agency (NFPA) 101® Life Safety Code® requires that “Interior wall or ceiling finish that is required elsewhere in this Code to be Class A, Class B, or Class C shall be classified based on test results from NFPA 255, ASTM E-84, or UL 723.”

2. How is the ASTM E84 test operate?

An ASTM E84 test is conducted by placing a 24” wide x 24’ long sample into a Steiner Tunnel (see description of Steiner Tunnel below), wherein the test is administered through the use of two burners which provide 89kW of energy. During the test, the sample is mounted on the ceiling under a removable lid, and a forced draft is provided in order for the movement of air and products of combustion within the tunnel, and to the exhaust/scrubber system. The progress of the flame is then monitored through viewports on one side of the apparatus and recorded, with software computing the various data points to derive the FSI and SDI. Smoke developed is also measured through the optical density of a light obscuration meter. It should be noted that the ‘fuel contributed’ measurement is no longer in use.

3. What is a Steiner Tunnel?

Developed by Albert Steiner in the 1940s, the Steiner Tunnel is a steel box lined on its sides and floor with fire brick and featuring a removable lid. The tunnel contains a 12-in. high fire chamber with two burners at one end providing 89kW of energy. The Steiner Tunnel was adopted as an ASTM Standard in 1950 and given the designation of E84.

4. ASTM E84 Steiner Tunnel Test (Flame Spread Test)

Tunnel test is to test the surface burning characteristics of materials, asbestos and untreated red oak plywood compared. 0 levels of asbestos plywood, 100 level for the untreated red oak flooring. In this test, the smoke produced during combustion also be measured, and divided into within the same class. This level within 10 minutes in the beginning was determined. However, the difference is coated with fire, building specifications to extend the test time from 10 minutes to 30 minutes, the burner flame propagation can’t exceed 10 1 / 2 feet, and requires no further signs of burning

Determination of the material with the tunnel of FSI between the value of between 0 to 200, FSI smaller the value of material, the smaller the risk of fire. High-rise building and the corridor should be used FSI <25 materials, 25 <FSI <100 can only be used for fire protection material is not very demanding place, and FSI> 100 of the material does not meet flame retardant requirements.


Flame-spread Index (FSI)

Smoke Development Index (SDI)

Class 1 / Class A


450 max

Class 2 / Class B


450 max

Class 3 / Class C


450 max




5. Is ASTM E84 the same as fire rated?

No, ASTM E84 certifies the system does not exceed the FSI and SDI values after 30 minutes of fire. A fire-rated system can withstand one hour of fire resistance without exceeding the FSI SDI thresholds. The only temporary containment option that meets this threshold is drywall. There isn’t currently a modular containment solution that meets the fire-rated standards.

In general, foam plastic insulation and foam plastic cores of manufactured assemblies shall be tested and labelled as having a flame spread index of not more than 75 and a smoke-developed index of not more than 450 (Class B) when they are tested in the maximum thickness intended.

Post time: Sep-17-2021