- Standard Number:
OSHA requirements are set by statute, standards and regulations. Our interpretation letters explain these requirements and how they apply to particular circumstances, but they cannot create additional employer obligations. This letter constitutes OSHA's interpretation of the requirements discussed. Note that our enforcement guidance may be affected by changes to OSHA rules. Also, from time to time we update our guidance in response to new information. To keep apprised of such developments, you can consult OSHA's website at https://www.osha.gov.
June 6, 2012
Pangeun Shim, General Manager
Doosan Heavy Industries and Construction Company
1303-22 Seocho-dong, Seocho-gu
Seoul, 137-920, Korea
Dear Mr. Shim:
Thank you for your letter dated October 11, 2011, to the Occupational Safety and Health Administration (OSHA) for a clarification of OSHA's Fixed Industrial Stairs standard, 29 CFR 1910.24. This constitutes OSHA's interpretation only of the requirements discussed and may not be applicable to any question not delineated within your original correspondence.
Your scenario and questions are paraphrased and our responses follow.
Background: OSHA standard 29 CFR 1910.24(e), states:
Fixed stairs shall be installed at angles to the horizontal of between 30 deg. and 50 deg. Any uniform combination of rise/tread dimensions may be used that will result in a stairway at an angle to the horizontal within the permissible range. Table D-1 gives rise/tread dimensions which will produce a stairway within the permissible range, stating the angle to the horizontal produced by each combination. However, the rise/tread combinations are not limited to those given in Table D-1.
Question #1: Would a fixed stair with any degree of angle to horizontal, however, assume 40 degrees for this question, with a tread run of 8 inches be acceptable?
Reply #1: No. Fixed stairs with a degree of angle to horizontal of 40 degrees with a tread run of 8 inches would not be acceptable. Fixed stairs with a tread run of 8 inches with a rise of 9.50 inches would be acceptable because it would produce an angle to horizontal of 49 degrees and 54 minutes, which is within the permissible range of 30 degrees to 50 degrees per 29 CFR 1910.24(e).
Question #2: Would fixed stairs with a degree of angle of between 38 degrees and 29 minutes to 41 degrees and 44 minutes be in compliance with 29 CFR 1910.24(e), if they have a rise of 7.75 to 8.25 inches and a tread run of 9.75 to 9.25 inches?
Reply #2: Yes. Fixed stairs are in compliance with the standard if the rise and tread run dimensions produce a stairway with an angle to horizontal between 30 and 50 degrees.
Question #3: Would fixed stairs with a degree of angle of between 38 degrees and 42 degrees be in compliance with 29 CFR 1910.24(e), if they have a rise of 7.07 to 8.15 inches and a tread run of 9.05 inches? Example #1: Fixed stair with a 39 degree of angle and a rise of 7.08 inches with a run of 9.05 inches. Example #2: Fixed stair with a 42 degree of angle and a rise of 8.15 inches with a run of 9.05 inches.
Reply #3: Yes. Please refer to the response to Question #2.
Thank you for your interest in occupational safety and health. We hope you find this information helpful. Please be aware that OSHA's enforcement guidance is subject to periodic review and clarification, amplification, or correction. Such guidance could also be affected by subsequent rulemaking. In the future, should you wish to verify that the guidance provided herein remains current, you may consult OSHA's website at http://www.osha.gov. If you have any further questions, please feel free to contact the Office of General Industry and Agriculture Enforcement at (202) 693-1850.
Thomas Galassi, Director
Directorate of Enforcement Programs