Archive Notice - OSHA Archive

NOTICE: This is an OSHA Archive Document, and may no longer represent OSHA Policy. It is presented here as historical content, for research and review purposes only.

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

January 21, 1976

Mr. F. Ward Hendee
Chief Draftsman
Vermont Structural Steel, Corp.
P.O. Box 610 207 Flynn Avenue
Burlington, Vermont 05401

Dear Mr. Hendee:

This is in response to your letter dated December 2, 1975, and confirms the telephone conversation between Mr. Barnier and a member of my staff concerning the diameter of standard pipe railings (29 CFR 1910.23(e)(3)(ii)).

The meaning of "nominal diameter" is explained in OSHA Program Directive #100-4 (copy enclosed) dated March 23, 1972. A "standard 1 1/4 inch 0 pipe (O.D. 1.660 inches)" meets the size requirements for pipe used in the construction of guard rails.

If I may be of any further assistance, please feel free to contact me.



John K. Barto, Chief
Division of Occupational Safety Programming