§ 1917.121. Spiral stairways.
207 words·~1 min read·
/us/cfr/t29/s§ 1917.121·A research copy — for the controlling text, always check the official state or federal source. Not legal advice.
(a)Definition. "Spiral stairway" means one with closed circular form, uniform sector-shaped treads and a supporting column.
(b)Requirements. Spiral stairways shall meet the following requirements:
(1)Stairways shall conform to the minimum dimensions of Figure F-1; ::: {width="100%"} ::: {.table_head} Spiral Stairway---Minimum Dimensions ::: ::: {.gpotbl_div} A (half-tread width) B Normal use by employees 11 inches (27.94 cm) 6 inches (15.24 cm). Limited access 9 inches (22.86 cm) 5 inches (12.7 cm). ::: :::
(2)Stairway risers shall be uniform and shall range from 6 1/2 to 10 1/2 inches (16.5 to 26.67 cm) in height;
(3)Minimum loading capability shall be 100 pounds per square foot (4.79kN), and minimum tread center concentrated loading shall be 300 pounds (1334 N);
(4)Railings shall conform to the requirements of § 1917.112(c)(1). If balusters are used, there shall be a minimum of one per tread. Handrails shall be a minimum of 1 1/4 inches (3.18 cm) in outside diameter; and
(5)Vertical clearance shall be at least 6 feet, 6 inches (1.98 m) above the top step.
(c)Maintenance. Spiral stairways shall be maintained in safe condition. \[48 FR 30909, July 5, 1983, as amended at 62 FR 40201, July 25, 1997; 65 FR 40942, June 30, 2000\]