What is the size of the test sample used in the Steiner Tunnel Test for evaluating surface burning characteristics?

The Steiner Tunnel Test is a standardized method used to assess the surface burning characteristics of building materials. It utilizes a test sample that measures 25 feet in length and 2 feet in width. This specific size is essential because it provides a standardized basis for comparing the combustion behavior of different materials in a controlled environment.

The 25 feet by 2 feet dimension allows for a sufficient length to observe flame spread and smoke production over time, which are critical factors in fire behavior and safety. This standardized measurement also facilitates consistent testing conditions, ensuring that results can be replicated and compared across different scenarios and materials. Thus, the specified size of 25 feet by 2 feet plays a vital role in evaluating and ensuring compliance with safety regulations regarding materials used in construction.