An inspector is reviewing the firestopping details for a roof assembly that penetrates a fire-resistance-rated wall. The penetration is for a large HVAC duct. According to IBC Section 714.4.1.2, what is the required fire-resistance rating of the firestop system at this penetration?
- AA minimum of 2 hours, regardless of the wall rating.
- BEqual to the fire-resistance rating of the roof assembly.
- CA minimum of 1 hour, regardless of the wall rating.
- DEqual to the fire-resistance rating of the wall.
Show answer & explanationAnswer & explanation
Correct answer: D. Equal to the fire-resistance rating of the wall.
IBC Section 714.4.1.2 (Penetrations of fire-resistance-rated walls) states that 'penetrations of fire-resistance-rated walls shall be protected by an approved firestop system or device installed and tested in accordance with ASTM E814 or UL 1479, with a F-rating equal to the fire-resistance rating of the wall, and a T-rating not less than 1 hour.' The question specifically asks for the fire-resistance rating of the firestop system, which is the F-rating.
Why the other options are wrong
- A. 2 hours is not a universal minimum; it depends on the wall's rating.
- B. The firestop rating is tied to the element being penetrated (the wall), not the penetrating element (the roof assembly).
- C. A minimum 1-hour T-rating is also required, but the F-rating (fire-resistance rating) must match the wall.
Firestop Rating (Wall Penetrations)
The required fire-resistance rating (F-rating) for a firestop system used to seal penetrations through fire-resistance-rated walls, ensuring the integrity of the fire barrier.
- Mandated by IBC Section 714.4.1.2.
- F-rating must match the wall's fire-resistance rating.
- A T-rating (temperature transmission) of at least 1 hour is also typically required.
Memory trick: Firestops seal holes with a rating matching the wall's shield.