705.8.5 Vertical separation of openings.
BC § 705.8.5
Openings in exterior walls in adjacent stories shall be separated vertically to protect against fire spread on the exterior of the buildings where the openings are within 5 feet (1524 mm) of each other horizontally. Such openings shall be separated vertically not less than 3 feet ( 914.4 mm) by spandrel girders, exterior walls or other similar assemblies that have a fire-resistance rating of not less than 1 hour, rated for exposure to fire from both sides, or by flame barriers that extend horizontally not less than 30 inches (762 mm) beyond the exterior wall and that are at least as wide as the opening. Flame barriers shall have a fire-resistance rating of not less than 1 hour. The unexposed surface temperature limitations specified in ASTM E 119 or UL 263 shall not apply to the flame barriers or vertical separation unless otherwise required by the provisions of this code. Where a curtain wall assembly is used on the exterior wall, the intersection between the floor assembly and curtain wall assembly shall be protected in accordance with Section 713.4 of this code. Exceptions: 1. This section shall not apply to buildings that are three stories or less above grade plane.
2.This section shall not apply to buildings equipped throughout with an automatic sprinkler system in accordance with Section 903.3.1.1 or 903.3.1.2.
3.This section shall not apply to open parking garages.
4.This section shall not apply to Occupancy Group A, E, I or R.
5.This section shall not apply where the opening in the lower story is a protected opening with a fire protection rating of at least 3/4 hour.
