Stair Angle and Tread Depth Requirements

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 17, 2025

Ray Mallory Kirby
421 W. Byrd Street
Timmonsville, SC 29161

Dear Mr. Kirby:

Thank you for your inquiry to the Occupational Safety and Health Administration (OSHA) regarding stair width and handrails. This letter constitutes OSHA's interpretation of only the requirements discussed and may not be applicable to any questions not delineated within your original correspondence. Your paraphrased background, question, and OSHA’s response are below:

Definition of Confined Space, as it may apply to large product heating and aging furnaces

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.

May 20, 2019

Mr. Anthony Green
Green Manufacturing Solutions
3000 Trailside Drive
Lexington, Kentucky 40511

Dear Mr. Green:

Thank you for your letter to the Occupational Safety and Health Administration (OSHA), regarding the definition of confined space1 at 29 CFR 1910.146, as it may apply to large product heating and aging furnaces. The background information and questions you provided in your inquiry are paraphrased below. OSHA’s responses follow your questions.