Commercial Building Inspector B2Public Safety and Special ConstructionHard
A building inspector is evaluating the fire separation between two attached commercial buildings. Building A is a two-story Group B office building, and Building B is a one-story Group S-1 storage warehouse. The buildings are separated by a fire wall. What is the minimum required fire-resistance rating for this fire wall, assuming both buildings are of Type II-B construction?
- A2-hour
- B1-hour
- C3-hour
- D4-hour
Show answer & explanationAnswer & explanation
Correct answer: D. 4-hour
According to IBC Table 706.4, 'Fire Wall Fire-Resistance Ratings', a fire wall separating a Group B occupancy from a Group S-1 occupancy, both being Type II-B construction, requires a 4-hour fire-resistance rating. The highest rating required for any occupancy group and construction type combination must be used.
Why the other options are wrong
- A. 2-hour rating can apply to some fire walls but is insufficient for B and S-1 occupancies with Type II-B construction.
- B. 1-hour is generally for fire barriers, not fire walls separating different buildings or occupancies of this type.
- C. 3-hour rating is typically for higher hazard occupancies or specific construction types, but 4-hour is required for this combination.
Fire Wall Rating (Occupancy Separation)
Fire walls are required to have a specific fire-resistance rating determined by the occupancy groups and construction types of the buildings they separate, ensuring complete fire separation.
- IBC Table 706.4 specifies ratings.
- Rating depends on occupancy and construction type.
- Higher rating governs when multiple apply.
Memory trick: Fire wall: Occupancy and construction decide the hourly shield.