(a) All treads shall have a nosing or effective projection of approximately one inch when risers are closed. The greatest riser height within any flight of stairs shall not exceed the smallest by more than three-eighths of an inch. Stairways shall not be less than three feet in clear width and shall have minimum headroom of six feet, eight inches and a rise and run of seven inches to eleven inches. Handrails may project from each side of a stairway a distance of three and one-half inches into the required width.
(b) Winders are permitted, provided the width of the tread at a point not more than twelve inches from the side where the treads are narrower is not less than nine inches, the width of any tread is not less than six inches, and the average width of any tread is not less than nine inches.
(c) Spiral stairways are permitted, provided the minimum width shall be twenty-six inches, with each tread having seven and one-half inches minimum tread width at twelve inches from the narrow edge. All treads shall be identical, and the rise shall be no more than nine and one-half inches. A minimum headroom of six feet, six inches shall be provided.
(Ord. 1992-101. Passed 1-14-92.)