PDFWAC 51-50-0706

Section 706—Fire walls.

706.6.1 Stepped buildings. Where a fire wall also serves as an exterior wall for a building and separates buildings having different roof levels, such wall shall terminate at a point not less than 30 inches (762 mm) above the lower roof level. Exterior walls above the fire wall extending more than 30 inches above the lower roof shall be of not less than 1-hour fire-resistance-rated construction from both sides with openings protected by fire assemblies having a fire protection rating of not less than 3/4 hour. Portions of the exterior walls exceeding 15 feet above the lower roof shall be permitted to be of nonfire-resistance-rated construction unless otherwise required by other provisions of this code.
EXEMPTION:
A fire wall serving as part of an exterior wall that separates buildings having different roof levels shall be permitted to terminate at the underside of the roof sheathing, deck or slab of the lower roof, provided items 1, 2, and 3 below are met. The exterior wall above the fire wall is not required to be of fire-resistance-rated construction, unless required by other provisions of this code.
 
1. The lower roof assembly within 10 feet (3048 mm) of the fire wall has not less than a 1-hour fire-resistance rating.
 
2. The entire length and span of supporting elements for the rated roof assembly has a fire-resistance rating of not less than 1 hour.
 
3. Openings in the lower roof are not located within 10 feet (3048 mm) of the fire wall.
[Statutory Authority: RCW 19.27.031 and 19.27.074. WSR 20-01-090, § 51-50-0706, filed 12/12/19, effective 7/1/20; WSR 16-03-064, § 51-50-0706, filed 1/19/16, effective 7/1/16.]