Surface flame spread Steiner tunnel test

As mentioned earlier, the fire hazard of interior finish materials is primarily due to the potential for rapid wind-aided flame spread over the surface. It is therefore not a surprise that reaction-to-fire requirements for interior finish materials in U.S. building codes are primarily based on performance in a wind-aided flame spread test. The apparatus of this test is often referred to as the Steiner tunnel. The Steiner tunnel test is described in ASTM E 84. Although the test does not measure any material properties that can be used in a model-based hazard assessment, a discussion of the test is included here due to its practical importance for the passive fire protection of buildings in the United States. 

ASTM E 286 Eight-Foot Tunnel Test. This test, a smaller version of the Steiner Tuimel Test (ASTM E 84), covers the measurement of surface flame spread of materials capable of being mounted and supported within a 13.75 in. (349-mm) x 8 ft. (2.44-m) test frame. The test also includes techniques for measuring the oke density and heat... 

In the United States, tests for surface flame spread of building materials were standardized as early as 1950. This so-called Steiner or 25-ft Tunnel Test is now codified as ASTM E 84-1981a. 

Steiner tunnel tests (ASTM E84) [127] measure the surface flame spread of a material. The specimen is exposed to an ignition source, and the rate at which the flames travel to the end of the specimen is measured. The severity of the exposure and the time a specimen is exposed to the ignition source are the main differences between the tunnel test methods [119]. The data obtained provide a measure of fire hazard, in that flame spread can transmit fire to more flammable materials in the vicinity and thus enlarge a conflagration, even though the transmitting material itself contributes little fuel to the fire. 

In the Steiner Tunnel of ASTM E 84-1981a (cf. Section 3.2.1, Fig. 3.93), flame spreading is measured on a specimen with surface area of 7320 mm x 508 mm. In the horizontal vent pipe of 408 mm dia. at the outlet of the tunnel, changes in the intensity of a vertical light beam are recorded during the test procedure. The area under the intensity vs, time curve for the specimen is divided by that for a red oak specimen and multiplied by 100, to establish a numerical index for comparison of the performance of the material to that of an asbestos-cement board and of red oak, taking these as limit points of an arbitrary centesimal scale (0 and 100, respectively). 

ANSI/ASTM E 84-79a - method of test for surface burning characteristics of building materials (Steiner tunnel). A 24-foot-long specimen is held horizontally as the roof of a 25-foot-long chamber. The ignition source is two gas burners, applied to the underside of one end. Flame spread is measured visually and instruments are used to determine fuel contribution and smoke density. The test is identical with UL 723 and ULC-S 102 1978, used in Canadian Building Regulations. 

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