The effective venting area shall not be less than 31/2 percent of the maximum shaft area at any floor, but in no event less than 72 square inches (0.05 m2).
Where a closed shaft or smoke vent duct penetrates through the roof of the building, the vent shall be located as follows:
- The vent shall be located at least 8 inches (203 mm) above a noncombustible roof assembly or at least 36 inches (914 mm) above a combustible roof assembly.
- The vent shall be located at least 10 feet (3048 mm) from any window, door, exterior stairway, or interior lot line. The vent may be located no less than 5 feet (1524 mm) from any window or door provided that the vent is located at a point higher than the top of such window or door.
- Where the vent is constructed as a window or louver, the sill of the window or louver shall be located at least 36 inches (914 mm)(above the roof assembly).
Where the exterior wall serves as part of a shaft enclosure or where a smoke vent duct penetrates the exterior wall of the building, no openings shall be located in the wall within a distance of 30 feet (9144 mm) vertically above the vent opening, nor within 5 feet (1524 mm) on either side of the vent opening.