Interpretation #9085
Published August 07, 2025
Original Request
- Code Version
- 2021
- Code
- BUILDING
- Code Description
- Chapter
- 4
- Section
- 406.5.2
- Topic
- Open Parking Garages Natural Ventilation Calculations
Question
Is the perimeter of a tier inclusive of both interior and exterior walls for natural ventilation calculations under Section 406.5.2?
Answer Published 08/06/2025 at 10:13 AM
Yes
Commentary
Section 406.5.2 states "The aggregate length of the openings considered to be providing natural ventilation shall be not less than 40 percent of the perimeter of the tier." The lengths of the interior east and north walls must be included in the 40% calculation, as they count toward the perimeter of the tier.