ICC Commercial Building Inspector Practice Test

What are the maximum dimensions for a square glass vision panel in a 1-1/2 hour rated door of a 2 hour rated fire wall?

1. 8" x 8"

2. 10" x 10"

3. 12" x 12"

4. 14" x 14"

The correct answer is: 10" x 10"

In the context of fire-resistance-rated assemblies, particular dimensions for vision panels within fire doors are specified to maintain the integrity of the fire barrier. For a 1-1/2 hour rated door that is installed within a 2-hour rated fire wall, the maximum dimensions of the glass vision panel are critical to ensuring that the performance characteristics of the door remain intact during a fire scenario. The standard maximum allowable size for a vision panel in this case is 10 inches by 10 inches. This limitation is established to minimize the risk of failure of the door and to prevent the spread of fire and smoke through the vision panel, which could compromise the effectiveness of the fire-rated assembly. When panels exceed this size, they could potentially compromise the fire rating due to increased heat exposure and thermal stress, leading to a greater risk of glass breakage or inability to serve its intended purpose in a fire event. Thus, the correct selection of 10" x 10" aligns with the guidelines set forth by relevant building codes and standards, which govern the use of vision panels in fire-rated doors to enhance safety and structural integrity in case of fire.