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 http://www.osha.gov.

March 15, 1990

Mr. Timothy F. Boland Senior Group Stress Engineer Martin Marietta Corporation P.O. Box 179 Denver, Colorado 80201

Dear Mr. Boland:

This is in response to your letter of October 9, 1989 concerning information relative to handrails (guardrails) provided by the Occupational Safety and Health Administration (OSHA) offices at Denver and San Francisco. This response supersedes previous correspondence regarding this subject. Please excuse the delay in response.

As you are aware, the design and construction of guardrailings and handrails requires that an acceptable margin of safety be provided by the completed assembly. In 1976, OSHA requested assistance from the National Bureau of standard (NBS) concerning guardrails. NBS produced a detail EO report addressing the subject. A copy of that report, NBS1R 76-1131, is enclosed.

In response to your several questions not covered by the NBS report, we provide the following:

1. Portable platforms shall be designed and constructed to meet or exceed the applicable industry consensus standard, such as but not limited to, ANSI A92.3. Generally, the platform structure shall provide for a safety factor of 3 times the rated loading relative to the yield strength of the materials of construction, but shall provide no less than a factor of safety of 4 times the ultimate strength of the materials of construction.

2. The platform structure shall react to and support at least 3 times the guardrail loads without permanent deformation of the platform components.

3. Stability required of the platform shall meet or exceed the specific stability requirements of the applicable industry consensus standard. In lieu of any applicable industry consensus standard the basic platform shall provide for a stability of 4 relative to an overturning moment resulting from a live load placed upon it.

If we may be of further assistance, please contact us.


Patricia K. Clark Director Designate Directorate of Compliance Programs