The Steiner tunnel is one of the most popular test methods within North America, used to carry out Fire Testing to determine the fire ratings of building interior walls & ceiling finishes for their ability propagate fire, and their tendency to emit smoke.

Steiner tunnel


The tunnel is constructed for test materials utilizing an exposed area 18 inches wide by 24 feet long and has a depth of 12 inches.

Specimens are set on the top of edge of the tunnel walls and are covered and enclosed by a single 25 foot refractory construction lid. This configuration is for flat or sheet samples in thickness up to as much as 4 inches.

Other Test Specimens?

Other test specimens, such as flooring and other shapes, are set on the tunnel floor. Specimens that melt or drip or cannot be adequately supported are also tested on the tunnel floor.

A controlled Natural Gas burner delivers a 90kw (300,000 BTU) flame throughout the test producing a 4½ foot flame as an ignition source to the specimen.

An automated system controls constant inlet draft of 240 feet per minute and is maintained for the 10-minute duration of the test.

In addition, a Thermocouple is positioned in the tunnel, at 23 feet from the flame source, to provide temperature information during the test process.

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