Subpart D
The Stairways standard covers standard, spiral, ship, and alternating tread-type stairs but excludes articulated stairs, scaffold stairs, stairs built into machines/equipment, and stairs on self-propelled equipment. See the application in 1910.25(a).
They must be provided wherever the Stairways standard requires them and in accordance with the handrail and guardrail rules in 1910.28. See the connection between 1910.25(b)(1) and 1910.28.
You must provide at least 6 feet, 8 inches (203 cm) of vertical clearance measured from the leading edge of the tread to any overhead obstruction. See 1910.25(b)(2).
Yes. Employers must ensure stair riser heights and tread depths are uniform between landings to prevent tripping hazards. See 1910.25(b)(3).
Landings and platforms must be at least as wide as the stair and at least 30 inches (76 cm) deep measured in the direction of travel. See 1910.25(b)(4).
You must provide a platform; its usable depth after the door or gate swing cannot be less than 20 inches (51 cm) for platforms installed before January 17, 2017, and not less than 22 inches (56 cm) for platforms installed on or after that date. See 1910.25(b)(5) and the subparagraphs 1910.25(b)(5)(i) and 1910.25(b)(5)(ii).
Each stair must support at least five times the normal anticipated live load but never less than a concentrated load of 1,000 pounds (454 kg) applied at any point. See 1910.25(b)(6).
Standard stairs must be used for regular, routine travel between levels; spiral, ship, or alternating tread-Type stairs may be used only when the employer demonstrates that standard stairs are not feasible. See 1910.25(b)(7) and 1910.25(b)(8).
When those stair types are allowed, they must be installed, used, and maintained according to the manufacturer's instructions. See 1910.25(b)(9).
Standard stairs must be installed at angles between 30 and 50 degrees; have a maximum riser height of 9.5 inches (24 cm); a minimum tread depth of 9.5 inches (24 cm); and a minimum width of 22 inches (56 cm) between vertical barriers. See 1910.25(c)(1), 1910.25(c)(2), 1910.25(c)(3), and 1910.25(c)(4).
No. The maximum riser height and minimum tread depth in paragraphs (c)(2) and (c)(3) do not apply to standard stairs installed prior to January 17, 2017. See 1910.25(c)(5).
Employers can meet the angle requirement by using the rise and tread combinations listed in Table D-1 or any other combination that achieves the 30–50 degree range. See Table D-1 and the compliance note in 1910.25(c)(1).
Spiral stairs must have a minimum clear width of 26 inches (66 cm), a minimum headroom of 6 feet, 6 inches (2 m) measured from the leading edge, and a minimum tread depth of 7.5 inches (19 cm) measured 12 inches (30 cm) from the narrower edge; treads must be uniform. See 1910.25(d)(1), 1910.25(d)(3), and 1910.25(d)(4).
Ship stairs must be installed at a slope of 50 to 70 degrees, have open risers with vertical rise of 6.5 to 12 inches (17–30 cm), a minimum tread depth of 4 inches (10 cm), and a minimum tread width of 18 inches (46 cm). See 1910.25(e)(1), 1910.25(e)(2), 1910.25(e)(3), and 1910.25(e)(4).
Alternating tread-type stairs must be installed at slopes of 50 to 70 degrees, have handrails spaced 17 to 24 inches (51–61 cm) apart, a minimum tread depth of 8.5 inches (22 cm), open risers if tread depth is less than 9.5 inches (24 cm), and a minimum tread width of 7 inches (18 cm) measured at the leading edge. See 1910.25(f)(1), 1910.25(f)(2), 1910.25(f)(3), 1910.25(f)(4), and 1910.25(f)(5).
No. These stair types may only be used when the employer demonstrates that providing standard stairs is not feasible; they also must be installed, used, and maintained per the manufacturer's instructions. See 1910.25(b)(8) and 1910.25(b)(9).
Measure standard stair width between vertical barriers; handrails are not considered vertical barriers and do not reduce the required minimum width. See 1910.25(c)(4) and the Stair width measurement guidance letter (Oct. 17, 2024) which explains that handrails are excluded when measuring width between vertical barriers.
OSHA does not prescribe a single test method in 1910.25(b)(6); it sets the performance requirement that stairs support five times the normal anticipated live load or at least a 1,000‑pound concentrated load. Employers should use accepted engineering practice or manufacturer guidance to demonstrate compliance. See 1910.25(b)(6) and the general handrail/guardrail requirements in 1910.28 for related design expectations.
Measure the 7.5‑inch minimum tread depth on spiral stairs at a point 12 inches (30 cm) from the narrower (inside) edge of the tread. See 1910.25(d)(4).
A landing must be at least the width of the stair it serves and 30 inches deep; if two stairs of different widths share a landing, each stair's required landing width must be provided so the landing meets the larger required width. See 1910.25(b)(4) and the door/gate swing rules at 1910.25(b)(5).
Yes. Compliance can be achieved by selecting a rise-and-run combination that matches one of the Table D-1 entries or any combination that results in a stair angle between 30 and 50 degrees, per 1910.25(c)(1) and Table D-1 in the standard.
Yes—ship stairs can have open risers, and the vertical rise between tread surfaces must be between 6.5 and 12 inches (17–30 cm). See 1910.25(e)(2).
Measure the distance between the two handrails across the stairway; it must be 17 to 24 inches (51–61 cm). Correct handrail spacing ensures users can grasp both rails while using alternating treads installed at 50–70 degrees. See 1910.25(f)(2) and the slope requirement in 1910.25(f)(1).
Winding stairways may be used on tanks and similar round structures only when the tank or structure has a diameter of at least 5 feet (1.5 m). See 1910.25(b)(7).
The 22‑inch minimum in 1910.25(c)(4) applies to places of employment and is measured between vertical barriers; means-of-egress width requirements are distinct and governed by other OSHA provisions such as 1910.35.
Yes—using devices like door closers or swing limiters is an accepted way to ensure the door's swing does not reduce the platform's effective usable depth below the required minimums (20 inches before Jan 17, 2017, or 22 inches on/after that date). Employers must still provide the platform meeting 1910.25(b)(5) and its subparts 1910.25(b)(5)(i) and 1910.25(b)(5)(ii).
No—handrails are not considered vertical barriers and therefore do not count as obstructions that reduce the required stair width measured between vertical barriers; measure between the vertical barriers themselves. See 1910.25(c)(4) and the Stair width measurement guidance letter (Oct. 17, 2024).