Commercial Building Inspector B2Wall Construction and Wall CoveringsMedium
A commercial building inspector is reviewing the plans for a new loading dock entry. The opening is in a 2-hour fire-resistance-rated exterior wall. The opening is protected by a fire door, and the fire separation distance is 15 feet (4572 mm). What is the maximum aggregate area of all openings permitted in any 100 square feet (9.3 m²) of the exterior wall area?
- A45 square feet (4.2 m²)
- B0 square feet (0 m²)
- C75 square feet (7.0 m²)
- DNo limit, as long as fire doors are installed
Show answer & explanationAnswer & explanation
Correct answer: A. 45 square feet (4.2 m²)
For a 2-hour fire-resistance-rated exterior wall with a fire separation distance between 11 feet and 30 feet (3353 mm and 9144 mm), the maximum aggregate area of protected openings is 45 square feet (4.2 m²) in any 100 square feet (9.3 m²) of the wall, according to IBC Table 705.8.
Why the other options are wrong
- B. 0 square feet applies to very small fire separation distances or specific fire walls.
- C. 75 square feet is for walls with less than 1-hour rating or larger separation distances.
- D. There are always limits on aggregate opening area, even with protected openings, in fire-rated exterior walls.
Exterior Wall Opening Aggregate Area
The maximum total area of protected openings permitted in a given section of a fire-resistance-rated exterior wall, based on fire separation distance and wall rating.
- Limits prevent excessive fire exposure through multiple openings.
- Fire separation distance is a critical factor.
- IBC Table 705.8 governs these requirements.
Memory trick: Exterior's holes: distance and rating set the roles.