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 15, 1997

Mr. Eric Ames Tilles
Morgan, Lewis and Bockius LLP
2000 One Logan Square
Philadelphia, PA 19103-6993

Dear Mr. Tilles:

This is in response to your letter of December 12, 1996, concerning the recently revised Occupational Safety and Health Administration (OSHA) standard addressing Scaffolds Used in the Construction Industry (subpart L, part 1926).

Your first comment refers to section §1926.451(e)(3), which requires a minimum step width of 16-inches, except for mobile scaffold stairway-type ladders where a minimum step width of 11 1/2 inches is required. You point out that many new scaffold designs have interior stair-ladders which are safer than exterior ladder access, but have only an 11 1/2 inch step width. As you may know, the Agency will be undertaking a rulemaking to address several other issues, and that forum would be appropriate to address this issue also. In the meantime, OSHA staff will issue an interpretation to the field staff, recognizing these interior stair-ladders, with instructions to consider their departure from the requirements of the standard to be "de minimis," that is, having no direct or immediate relationship to safety and health.

Your second comment refer to section §1926.451(a)(2), specially the relationship of rated load to stall load of the hoist being used. I believe that OSHA has responded to your concerns on this issue in the compliance directive (CPL 2-1.23) which I am enclosing for your convenience.

A footnote to your comment on section §1926.451(a)(2) also suggests that OSHA clarify the weight of the scaffold is not included in the calculations for four times the maximum intended load applied or transmitted. OSHA believes that section 1926.451(a)(1) as written along with the definition of "maximum intended load" found in section 1926.450, provides adequate clarification as to OSHAs' intent.

Your next comment is directed to the overhang permitted for planks 10 feet or less in length. You state that OSHA changed the provision from the proposal without receiving any comment on the provision and without prior notice to stakeholders. Please be advised that while no formal comment was received on the provision, the language in the final rule was based on language developed at ANSI meetings and which appeared in draft revisions of the ANSI A10.8 standard for scaffolds. This language was subsequently not adopted by ANSI. However, I would like to point out that under the revised OSHA regulation, planks can have an overhang greater than 12-inches if the platform is designed and installed so that the cantilevered portion of the platform can support loads without tipping, or has guardrails which block employee access to the cantilevered end. In addition, the rule does not require 16-foot planks to be centered when spanning 14-foot spaces. That situation is covered by paragraph 1926.451(b)(5)(ii) .

Your comment directed at section 1926.451(d)(1) is inaccurate in that the paragraph does not apply to the floor or roof. As indicated in the preamble, OSHA is addressing the surfaces that support outrigger beams, cornice hooks or parapet clamps. These are normally bearing blocks which are placed on the parapets.

Your comment directed at section §1926.451(e)(4)(xii) ((sic xiii)) is also inaccurate. OSHA intends that the term "flight" means the stairs between platforms. Each-flight has the 1/4 inch tolerance. There is no restriction between flights: one flight could have 7-inch risers and another could have 8-inch risers. The second sentence of this provision addresses the bottom flight and top flight of the total system where a greater distance is allowed to accommodate the first step onto the system and the last step off the system.

Many of your other concerns have been addressed either in the compliance directive which I am enclosing or through letters of interpretation which have been prepared by my staff. Many of the letters of interpretation will appear on the Internet or in future updates of the OCIS CD-ROM.

Finally, a meeting of the Advisory Committee on Construction Safety and Health (ACCSH) workgroup set up to develop recommendations on the format and content of Non-mandatory Appendix B was held in Washington, D.C. on March 11 and 12, 1997. Both the SIA and the SSFI were in attendance at the meeting. In addition, input from interested parties can also be sent in to the OSHA docket office, in accordance with the instructions provided in the Federal Register document of August 30, 1996.

If you have any further questions, please contact: The Office of Construction Standards and Compliance Assistance, U.S. Department of Labor-OSHA, 200 Constitution Avenue N.W., Room N3621, Washington, D.C. 20210.


Roy F. Gurnham, Manager
Office of Construction Standards
and Compliance Assistance