Temporary Stairway Check (OSHA 1926.1052)
The construction stairway, governed differently from a finished one in three ways.
Example
You enter
- Risers in the flight 3
- Total rise (in; 0 = risers x riser height) 32
- Riser height (in) 10.67
- Tread depth (in) 11
- Largest riser-height variation in the flight (in) 0.5
- Largest tread-depth variation in the flight (in) 0.125
You get
- Angle (30-50 degrees) 44.1 deg - in range
- Total rise used (in) 32
- Worst variation (in) 0.5
Checked against published worked examples from: Occupational Safety and Health Administration.
Details, formula, and sources
ScopeThe stairrail trigger is a double condition read the unusual way -- four or more risers OR rising more than 30 in, WHICHEVER IS LESS, meaning whichever comes FIRST -- so a three-riser flight climbing 32 in is caught by the rise even though it fails the riser count. The angle is bounded on BOTH sides, 30 to 50 degrees: too shallow is a violation, not a courtesy, because a run under 30 degrees is a ramp with steps in it and people trip on it precisely because it does not read as stairs. And uniformity is a VARIATION ACROSS THE FLIGHT, not a tolerance per step -- not over 1/4 in in any stairway system, so individually reasonable steps still fail if the first and last differ.
Formula or tableangle = atan(riser height / tread depth) in degrees, required between 30 and 50; a stairrail is required where risers >= 4 OR total rise > 30 in (whichever comes first); uniformity passes where the worst of the riser-height and tread-depth variations is <= 1/4 in; stairrail height >= 36 in from its upper surface to the tread surface; landing depth >= 30 in in the direction of travel.
Source and editionOSHA 29 CFR 1926.1052, Subpart X - Stairways and Ladders. A US federal regulation in the public domain, quoted directly.
Free access29 CFR is published in full at no cost by OSHA and the eCFR.
What governsEstimate. AHJ and licensed professional govern.
API field namesriser_count, total_rise_in, riser_height_in, tread_depth_in, riser_variation_in, tread_variation_in, angle_deg, total_rise_used_in, worst_variation_in
- Angle between 30 and 50 degrees from horizontal - bounded both ways29 CFR 1926.1052(a)
- Stairrail trigger four or more risers OR rising more than 30 in, whichever comes first29 CFR 1926.1052(c)(1)
- Stairrail height not less than 36 in from the upper surface to the tread, post-199129 CFR 1926.1052(c)
- Uniformity variation not over 1/4 in ACROSS the flight, not per step29 CFR 1926.1052(a)
- Landing depth not less than 30 in in the direction of travel, at every 12 ft or less of rise29 CFR 1926.1052(a)
- Not checked landing width, handrails, midrails, metal pan treads, spiral and alternating treadsstated scope limit