Fire exit hardware must be provided in Group I-1, I-2, and I-4 occupancies on exit doors leading to the exterior and doors from exit stairways leading to the interior of the building on the level of exit discharge.
14X-5-505.8.5 Revolving and power-operated doors.
Revolving doors, power-operated doors, and special-purpose sliding, accordion, or folding doors must be maintained to meet the requirements in effect at the time of construction or the requirements of the Chicago Building Code.
14X-5-505.9 Stairways.
Stairways which are part of the means of egress must comply with this section.
14X-5-505.9.1 Tread and riser dimensions.
Existing stairways which meet the dimensional requirements of Sections 14X-5-505.9.1.1 through 14X-5-505.9.1.3 may remain in use.
14X-5-505.9.1.1 Rise and run.
The rise must not exceed 8-1/4 inches (210 mm) and the depth of treads must be at least 9 inches (229 mm).
Exception: Conditions allowed by the Chicago Building Code.
14X-5-505.9.1.2 Winders.
Winders must have a minimum tread depth of 9 inches (229 mm) at a point 18 inches (457 mm) from the narrowest edge.