Nick
Registered User
IBC 2015, IIIB, R-2, 4 STORY
The majority of the building is 4 story, with a 4 story Interior Exit Stairway at each end of the building. 2-hour rating on all exterior (load bearing) walls, including the exterior walls that form 2 of 4 sides of the Interior Exit Stairway. Unlimited unprotected windows allowed with 30' + of separation.
Adjacent to the stair tower, part of the same building is only 2 story. I can't find in the code a requirement to protect the windows in the exterior wall in the Interior Exit Stairway, or the lower roof below these unprotected windows.
Section 1023.7 in part says "Where nonrated walls or unprotected openings enclose the exterior of the stairway or ramps and the walls or openings are exposed by other parts of the building at an angle of less than 180 degrees (3.14 rad), the building exterior walls within 10 feet (3048 mm) horizontally of a nonrated wall or unprotected opening shall have a fire-resistance rating of not less than 1 hour. Openings within such exterior walls shall be protected by opening protectives having a fire protection rating of not less than 3/4 hour."
Does "other parts of the building" include the lower roof?
Logically, I think it does, but then the rest of the section talks specifically about walls and unprotected openings.
The other section that comes to mind is 705.8.6 Vertical Exposure - but Exception #2 gets us out of that requirement I believe:
705.8.6 Vertical Exposure
For buildings on the same lot, opening protectives having a fire protection rating of not less than 3/4 hour shall be provided in every opening that is less than 15 feet (4572 mm) vertically above the roof of an adjacent building or structure based on assuming an imaginary line between them. The opening protectives are required where the fire separation distance between the imaginary line and the adjacent building or structure is less than 15 feet (4572 mm).
Exceptions:
Thanks
The majority of the building is 4 story, with a 4 story Interior Exit Stairway at each end of the building. 2-hour rating on all exterior (load bearing) walls, including the exterior walls that form 2 of 4 sides of the Interior Exit Stairway. Unlimited unprotected windows allowed with 30' + of separation.
Adjacent to the stair tower, part of the same building is only 2 story. I can't find in the code a requirement to protect the windows in the exterior wall in the Interior Exit Stairway, or the lower roof below these unprotected windows.
Section 1023.7 in part says "Where nonrated walls or unprotected openings enclose the exterior of the stairway or ramps and the walls or openings are exposed by other parts of the building at an angle of less than 180 degrees (3.14 rad), the building exterior walls within 10 feet (3048 mm) horizontally of a nonrated wall or unprotected opening shall have a fire-resistance rating of not less than 1 hour. Openings within such exterior walls shall be protected by opening protectives having a fire protection rating of not less than 3/4 hour."
Does "other parts of the building" include the lower roof?
Logically, I think it does, but then the rest of the section talks specifically about walls and unprotected openings.
The other section that comes to mind is 705.8.6 Vertical Exposure - but Exception #2 gets us out of that requirement I believe:
705.8.6 Vertical Exposure
For buildings on the same lot, opening protectives having a fire protection rating of not less than 3/4 hour shall be provided in every opening that is less than 15 feet (4572 mm) vertically above the roof of an adjacent building or structure based on assuming an imaginary line between them. The opening protectives are required where the fire separation distance between the imaginary line and the adjacent building or structure is less than 15 feet (4572 mm).
Exceptions:
- Opening protectives are not required where the roof assembly of the adjacent building or structure has a fire-resistance rating of not less than 1 hour for a minimum distance of 10 feet (3048 mm) from the exterior wall facing the imaginary line and the entire length and span of the supporting elements for the fire-resistance-rated roof assembly has a fire-resistance rating of not less than 1 hour.
- Buildings on the same lot and considered as portions of one building in accordance with Section 705.3 are not required to comply with Section 705.8.6.
Thanks
