Commercial Building Inspector B2Wall Construction and Wall CoveringsMedium
A commercial building inspector is reviewing the fire-resistive construction for an interior exit stairway wall in a five-story office building. The building is Type IIIA construction. What is the minimum fire-resistance rating required for this interior exit stairway wall?
- A1-hour
- B3-hour
- C4-hour
- D2-hour
Show answer & explanationAnswer & explanation
Correct answer: D. 2-hour
According to IBC Table 1023.2, interior exit stairway walls in buildings of Type IIIA construction that are four stories or more in height (this is a five-story building) require a minimum 2-hour fire-resistance rating.
Why the other options are wrong
- A. 1-hour rating is typically for buildings of three stories or less, or specific non-exit elements.
- B. 3-hour rating is typically for higher hazard occupancies or specific conditions like high-rise buildings.
- C. 4-hour rating is reserved for highly specific, high-risk scenarios or very tall buildings, not standard for this case.
Interior Exit Stairway Fire Rating
The fire-resistance rating required for interior exit stairway enclosures varies based on building height and construction type to ensure safe egress during a fire.
- Ratings are determined by IBC Table 1023.2.
- Building height (stories) is a critical factor.
- Construction type (e.g., Type IIIA, Type IB) also influences the rating.
Memory trick: Stairway's Shield: Stories, Structure, Safety.