Interpretation #7106

Original Request

Code Version: 2010
Code: BUILDING
Code Description: Building
Chapter: 4
Section: 406.3.3.1
Topic: 4-story parking garage

Question

The project is a 4-story, R-2, Type V-A, NFPA 13R, building which surrounds a 4-story, S-2, Type II-B, NFPA 13, structured parking garage. The structured parking garage abuts the residential building on two adjacent sides. The remaining two adjacent sides are separated by a distance of at least 10 feet from the residential building, creating voids that are open to the sky. The residential building's walls that face the parking garage are of 2-hour fire-resistance rated occupancy an area separation. Does such 4-story parking garage, having two adjacent and perpendicular perimeter walls that have openings amounting to more than 20 percent of the total perimeter wall area and more than 40 percent of the lineal perimeter length of each parking garage tier, meet the natural ventilation requirements of 2010 FBC section 406.3.3.1 to be classified as an Open Parking Garage when such perimeter walls are separated from other wall constructions by a distance of 10 feet or more that is open to the sky?

Answer Published 11/19/2012 at 9:42 AM

Yes with a caveat, The minimum 10 feet comes from Table
602 via 406.3.7. The removal of a fire-restive rating comes
from footnote “d”. Due to this requirement of a Fire
Separation Distance, the potential of an adjacent property
to have a wall at the property line is understood.

Commentary

The openings must be uniformly distributed. The buildings being described will most likely be divided by Fire Walls or “assumed lot lines” not an Occupancy Separation.