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.

November 15, 1990

Mr. Ole E. Leivestad, P.E.
Chief Engineer
Spider Staging Corporation
Corporate Headquarters
13536 Beacon Coal Mine Road. S
Seattle, Washington 98178

Dear Mr. Leivestad:

This is in response to your inquiry of August 7, concerning the Occupational Safety and Health Administration (OSHA) interpretation of the OSHA standard at 29 CFR 1910.66(e)(2)(iii)(A)(5), which pertained to intermittent stabilization system building anchors and components for powered platforms for exterior building maintenance. You wrote your letter as a result of our interpretation (of July 10, to Mr. Kirk E. Osgood of CDC Inc. of Dallas, Texas) of the OSHA standard stated earlier. We apologize for the delay in our response.

We have further reviewed our interpretation stated above, and determined that the intermittent stabilization system components of powered platforms must be capable of sustaining an ultimate design load of at least 600 pounds. This ultimate strength is consistent with the strength described in OSHA Instruction STD 1-3.3, November 1, 1982, a copy of which is enclosed. However, please note that the strength described in this letter is ultimate strength and not the tensile strength.

We wrote another letter to Mr. Osgood (copy enclosed), explaining the factors that were originally considered in out July 10th interpretation, and the factors that are presently considered. The second letter to Mr. Osgood, however, clarifies that the anchors or components associated with the intermittent stabilization system for powered platforms need not be designed to withstand an ultimate strength of 1200 pounds, but must be designed to sustain an ultimate strength of at least 600 pounds.

We apologize for any inconvenience caused to you by our previous interpretation. Thank you for your interest in occupational safety and health.


Patricia K. Clark, Director
Directorate of Compliance Programs