Commercial Building Inspector B2Floor ConstructionMedium
A commercial building inspector is reviewing the firestopping details for penetrations through a 2-hour fire-resistance-rated concrete floor slab. A 4-inch (102 mm) PVC pipe penetrates the slab. According to the IBC, what is the minimum required fire-resistance rating for the firestop system around this penetration?
- A1.5 hours
- B1 hour
- C2 hours
- D3 hours
Show answer & explanationAnswer & explanation
Correct answer: C. 2 hours
IBC Section 714.3 requires that penetrations through fire-resistance-rated floor assemblies be protected by an approved firestop system that is tested and rated for a fire-resistance rating not less than the rating of the assembly penetrated. Therefore, for a 2-hour rated floor, a 2-hour firestop system is required.
Why the other options are wrong
- A. 1.5 hours is not a standard firestop rating increment specified for matching assembly ratings in the IBC.
- B. 1 hour would be insufficient for a 2-hour rated floor assembly.
- D. 3 hours would exceed the requirement and is unnecessary for a 2-hour rated assembly.
Firestop Rating
Firestop systems are crucial for maintaining the fire-resistance rating of assemblies when penetrated by pipes, conduits, or cables, preventing the spread of fire and smoke.
- Rating must match the assembly penetrated.
- Tested in accordance with ASTM E814 or UL 1479.
- Includes F-rating (flame) and T-rating (temperature).
- Specific systems for different penetrating items (e.g., plastic pipe, metal conduit).
Memory trick: Penetration's seal, assembly's appeal, match the fire's zeal.