During the construction of any reinforced concrete building or other structure, at least one stairway shall be installed which shall extend to a level not more than four floors or 60 feet, whichever is less, below the uppermost working floor or level. During the construction of other types of buildings or other structures, at least one stairway shall be installed which extends to a level not more than two floors or 30 feet, whichever is less, below the uppermost working floor or level. Such stairways shall be extended upward as the construction progresses to comply with this Part (rule).

Temporary stairways shall have treads constructed of wood planks not less than two inches by 10 inches in size, or metal not less than two inches in depth of equivalent strength. Such temporary stairways shall be not less than three feet in width and shall be substantially constructed and rigidly braced. Such stairways more than five feet in width shall be provided with intermediate or center stringers. Stairways with steel treads and landings which are to be subsequently filled in with concrete or provided with other permanent tread surfacing shall be provided temporary wooden treads carefully fitted in place and extending to the edges of the metal nosing and over the full width of the treads and landings.

Skeleton iron or steel stairs shall have treads of wood planking not less than two inches by 10 inches in size.

Any temporary stairway shall not have a vertical rise of more than 12 feet between landings or floors.

The stairwells of temporary wooden stairways and of permanent stairways where enclosures or guard rails have not been erected shall be provided with a safety railing constructed and installed in compliance with this Part (rule) on every open side. Every stairway and landing shall be provided with handrails not less than 30 inches nor more than 40 inches in height, measured vertically from the nose of the tread to the top of the rail.