Standard Interpretations - Table of Contents
• Standard Number: 1926.502(b)(1)

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

February 1, 1999

Steven J. Hess
Sr. Safety Manager
CECO Concrete Construction, L.L.C
P.O. Box 28570
Kansas City, MO 64188

Re: 29 CFR 1926.502(b)(1)

Dear Mr. Hess:

Thank you for your letter dated July 1, 1998, to the Occupational Safety and Health Administration (OSHA) requesting clarification of 29 CFR 1926.502(b)(1) (guardrail height) as it applies to cast-in-place concrete structures. In your letter, you provide an example of a situation where employees perform work at a site that has two walking/working surfaces of different elevations (see attached diagram A). The lower elevation surrounds the higher elevation. You state that your company has a policy of placing guardrails on both surfaces if the height difference between the two elevations exceeds six feet. However, where the height difference is less than six feet, you do not put a guardrail on the upper surface. Instead, you use the guardrail on the lower surface to protect workers on the upper surface. You have a method for determining how high that lower lever guardrail n