(A) Head room. Minimum six feet eight inches continuous clear head room shall be maintained. The height shall be measured vertically from the stair nosing to a line parallel with the run of the stair.
(B) Width. All stairs shall be minimum three feet wide. Basement stairs may be two feet six inches clear of the handrail.
(C) Treads. All treads shall be a minimum of ten and one-half inches in width including nosing and shall be uniform in width.
(D) Winding stair treads. Winding stair treads shall be not less than nine and one-half inches wide at a point 15 inches from the converging end of the tread when designed as a required means of egress. Metal barrel stairs and wood stairs with smaller dimensions noted above may be used when designed as a secondary means of egress.
(E) Rise. The rise of each step shall be not more than seven and three-fourths inches. The height of each riser in a stair run shall be uniform in height.
(F) Landing. A minimum landing, three feet by three feet, shall be required on each side of an egress door. The floor or landing shall not be more than one and one-half inches lower than the top of the threshold:
(1) Exception. At the top of an interior flight of stairs, provided the door does not swing over the stairs; and
(2) Exception. The landing at the exterior of an exterior doorway shall not be more than eight and one-half inches below the top of the threshold.
(G) Handrail. Handrails having minimum and maximum heights of 30 inches and 34 inches respectively, measured vertically from the nosing of the treads shall be provided, on at least one side of stairways of three or more risers.
(1) Opening limitations. In buildings of Use Group R, open guards shall have balusters or other construction such that a sphere with a diameter of four inches (102 mm) cannot pass through any opening.
(2) Exception. The triangular openings formed by the riser, tread and bottom rail at the open side of a stairway shall be of such size that a sphere six inches (152 mm) in diameter cannot pass through the opening.
(H) Porches, balconies, floors or platform surfaces. Porches, balconies, floors or platform surfaces located 24 inches or more above the floor or grade below shall be provided with railings not less than three feet high.
(I) Underside. The underside of stairs and platforms leading to habitable rooms shall be protected with one-half inch Type “X” gypsum board or approved equal.
(Prior Code, § 9-101) (Ord. 94-11B, passed 4-21-1994)