This article covers the new Subpart D stairways (29 CFR 1910.25 a – c) standards and the exception. Subpart D 29 CFR 1910.25 d – f were covered in a previous Safety Spotlight article.

1910.25 (a) Application – This section covers all stairways (including standard, spiral (d), ship (e) and alternating tread-type stairs (f)). Except for stairs serving floating roof tanks, stairs on scaffolds, stairs designed into machines or equipment, and stairs on self-propelled motorized equipment.

1910.25 (b) General Requirements – The employer must ensure:

     (1) Handrails, stair rail systems and guardrail systems are provided in accordance with 1910.28.

     (2) Vertical clearance above any stair tread to any overhead obstruction is at least 6 feet, 8 inches, as measured from the leading edge of the tread.

     (3) Stairs have uniform riser heights and tread depths between landings;

     (4) Stairway landings and platforms are at least the width of the stair and at least 30 inches in depth, as measured in the direction of travel;

     (5) When a door or a gate opens directly on a stairway, a platform is provided, and the swing of the door or gate does not reduce the platform’s effective usable depth to:

                      (i) less than 20 inches for platforms installed before January 17, 2017; and

                      (ii) less than 22 inches for platforms installed on or after January 17, 2017


     (6) Each stair can support at least five times the normal anticipated live load, but never less than a concentrated load of 1,000 pounds applied at any point;
     (7) Standard stairs are used to provide access from one walking-working surface to another when operations necessitate regular and routine travel between levels, including access to operating platforms for equipment. Winding stairs may be used on tanks and similar round structures when the diameter of the tank or structure is at least 5 feet.
     (8) Spiral, ship, or alternating tread-type stairs are used only when the employer can demonstrate that it is not feasible to provide standard stairs.
     (9) When paragraph (b)(8) of this section allows the use of spiral, ship or alternating tread-type stairs, they are installed, used and maintained in accordance with manufacturer’s instructions.   
(c) Standard stairs – In addition to paragraph (b) of this section, the employer must ensure standard stairs:
     (1) Are installed at angles between 30 to 50 degrees from the horizontal;
     (2) Have a maximum riser height of 9.5 inches;
     (3) Have a minimum tread depth of 9.5 inches; and
     (4) Have a minimum width of 22 inches between vertical barriers (see Figure D-8 below) 
The requirements of paragraphs (c)(2) and (3) do not apply to standard stairs installed prior to January 17, 2017. OSHA will deem those stairs in compliance if they meet the dimension requirements specified in Table D-1 of this section or they use a combination that achieves the angle requirements of paragraph (c)(1) of this section. 
Table D-1 -- Stairway Rise and Tread Dimensions
Angle to horizontal Rise (in inches) Tread run (in inches)
30 deg. 35' 6 1/2 11
32 deg. 08' 6 3/4 10 3/4
33 deg. 41' 7 10 1/2
35 deg. 16' 7 1/4 10 1/4
36 deg. 52' 7 1/2 10
38 deg. 29' 7 3/4 9 3/4
40 deg. 08' 8 9 1/2
41 deg. 44' 8 1/4 9 1/4
43 deg. 22' 8 1/2 9
45 deg. 00' 8 3/4 8 3/4
46 deg. 38' 9 8 1/2
48 deg. 16' 9 1/4 8 1/4
49 deg. 54' 9 1/2 8