Spiral stairways.

  1. Law
  2. CFR 29
  3. Labor
  4. Regulations Relating to Labor
  5. Occupational Safety and Health Administration, Department of Labor
  6. Marine Terminals
  7. Terminal Facilities
  8. Spiral stairways.

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§ 1917.121 Spiral stairways.

(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;

Expand Table

Spiral Stairway - Minimum Dimensions

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 61⁄2 to 101⁄2 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 11⁄4 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]


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