How high are walls for a corner test?

• A. 15 Feet
• B. 25 Feet
• C. 30 Feet
• D. 20 Feet

Answer: (B)

Corner tests use a defined wall height to simulate the exposure a building corner would impose on a fire. The height is set to 25 feet because it provides enough vertical room for flames and hot gases to behave like they would in a typical two-story or taller structure, while keeping the test setup practical and reproducible. This height yields consistent flame spread and heat flux on the test surfaces, which is essential for evaluating materials and construction features. Shorter heights (like 15 or 20 feet) can under-represent heat exposure, and a much taller setup (such as 30 feet) can change the dynamics and complicate the test. Therefore, 25 feet is the standard height used.