Exterior stair width

[chris macko]

(IBC 2021/Chicago building code 2019) Per 1005.3, stairways need to be sized for 0.3" per occupant for a non-sprinklered building, with 48" minimum between handrails, and at 0.2" per occupant for a sprinklered building, with 44" clear not counting handrail projections. I've always interpreted this to include the exterior stairs as well when the building is sprinklered, even though the exterior stair itself technically isn't sprinklered. I've recently heard the argument that since the sprinklers don't extend outside over the stairs, it still needs to follow the non-sprinklered sizing requirements. Is this condition addressed anywhere in the code directly?

 

[RLGA]

NFPA 13, Section 9.3.4.2.4, permits sprinklers to be omitted from exterior stairways when the open area is at least 50% and they are entirely of noncombustible construction.

I do not see many combustible exterior stairways.

 

[chris macko]

Yes, they will be steel grate stairs. Perfect, thanks!