Stairways and Vertical Openings

Section 370 Section 370.2350  Stairways and Vertical Openings a)         Interior stairways shall be enclosed with construction having a 1-hour fire resistance rating, exit directly to outside grade and have a door at all floors. b)         Light or ventilation shaft, chute and other vertical openings between stories shall be enclosed with construction having a 1-hour fire resistance rating. c)         Every multi-level facility shall have stairways with a minimum headroom of six (6) feet, eight (8) inches and a maximum height of twelve (12) feet between landings; a minimum clear width of three (3) feet, except handrails which may project not more than three and one-half (3½) inches on each side, a handrail is required only on one side of the stair. The width of treads exclusive of nosing or projection shall be not less than nine (9) inches and risers shall be not more than eight (8) inches.  Stairways with triangular or winding treads or single risers are not acceptable. d)         Every stairway shall have a landing that is at least as deep as the width of the stairway door. e)         Usable space under stairs shall not be used for storage. f)         Means of egress such as stairs, stair landings, balconies, ramps and aisles, located along the edge of open-sided floors and mezzanines, shall have guardrails to prevent falls over the open side.  Each new stair shall have handrails on at least one side.