Commercial Building Inspector B2Floor ConstructionMedium
A commercial building inspector is reviewing the plans for a new four-story mixed-use building. The structural drawings indicate that the floor system consists of steel beams and girders supporting a composite metal deck with a concrete slab. What is the minimum fire-resistance rating required for the floor construction separating a Group M occupancy from a Group R-2 occupancy in this building, constructed as Type IIIA?
- A3 hours
- B1 hour
- C2 hours
- D4 hours
Show answer & explanationAnswer & explanation
Correct answer: C. 2 hours
According to IBC Table 508.4, separations between different occupancies must have fire-resistance ratings as specified. For a Group M separated from a Group R-2, the required fire-resistance rating for the floor construction is 2 hours.
Why the other options are wrong
- A. This rating is for higher hazard separations or specific structural elements in certain building types, not applicable here.
- B. This is the required rating for some other occupancy separations or for non-bearing walls in certain building types, but not for M from R-2.
- D. This rating is typically for very high hazard conditions or specific structural elements in high-rise buildings.
Occupancy Separation Fire Rating
The minimum fire-resistance rating required for an assembly that separates adjacent occupancies of different hazard levels within a building.
- Determined by occupancy groups involved.
- Found in IBC Table 508.4.
- Critical for life safety and fire containment.
Memory trick: Occupancy separation ratings are like firewalls between different building functions.