Commercial Building Inspector B2Roof Ceiling ConstructionEasy
An inspector is reviewing plans for a new commercial building. The plans indicate a wood-framed roof structure over a Group A-2 occupancy. The roof assembly is proposed to have a fire-resistance rating of 1 hour. What is the minimum required fire-resistance rating for the roof construction in this scenario, assuming the building is not equipped with an automatic sprinkler system throughout?
- A0 hours
- B2 hours
- C1.5 hours
- D1 hour
Show answer & explanationAnswer & explanation
Correct answer: D. 1 hour
According to IBC Table 601, for a Group A-2 occupancy, the minimum fire-resistance rating for roof construction is 1 hour if the building is not sprinklered throughout.
Why the other options are wrong
- A. 0 hours is typically for unprotected noncombustible construction or specific minor occupancies.
- B. 2 hours is typically required for higher hazard occupancies or specific building types, not generally for A-2 roofs.
- C. 1.5 hours is not a standard minimum rating for roof construction in this context.
Roof Fire-Resistance Rating (Group A-2)
The minimum time a roof assembly must withstand fire exposure for a Group A-2 occupancy without an automatic sprinkler system.
- Determined by occupancy group and building type.
- Table 601 of the IBC specifies ratings.
- Automatic sprinkler systems can sometimes reduce required ratings.
Memory trick: Fire ratings protect roofs like shields against flames.