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Regulations (Standards - 29 CFR) - Table of Contents
• Part Number: 1917
• Part Title: Marine Terminals
• Subpart: F
• Subpart Title: Terminal Facilities
• Standard Number: 1917.121
• Title: Spiral stairways.
• GPO Source: e-CFR


Definition. "Spiral stairway" means one with closed circular form, uniform sector-shaped treads and a supporting column.


Requirements. Spiral stairways shall meet the following requirements:


Stairways shall conform to the minimum dimensions of Figure F-1;

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)


Stairway risers shall be uniform and shall range from 6½ to 10½ inches (16.5 to 26.67 cm) in height;


Minimum loading capability shall be 100 pounds per square foot (4.79 kN), and minimum tread center concentrated loading shall be 300 pounds (1334 N);


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 1¼ inches (3.18 cm) in outside diameter; and



Vertical clearance shall be at least 6 feet, 6 inches (1.98 m) above the top step.


Maintenance. Spiral stairways shall be maintained in safe condition.

[62 FR 40141, July 25, 1997; 65 FR 40942, June 30, 2000]

Next Standard (1917.122)

Regulations (Standards - 29 CFR) - Table of Contents

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