Stairways shall be not less than 36 inches (914 mm) in clear width at all points above the permitted handrail height PHOTO 1 & 2 and below the required headroom height PHOTO 2. The clear width of stairways at and below the handrail height, including treads and landings, shall be not less than 31½ inches (787 mm) where a handrail is installed on one side PHOTO 3 and 27 inches (698 mm) where handrails are installed on both sides PHOTO 4. Exception: The width of spiral stairways shall be in accordance with Section R311.7.10.1 See PHOTO 52 (p. 19).