Standard Interpretations - Table of Contents
• Standard Number: 1926.502; 1926.452(x)(9); 1926.450(b); 1926.502(d)(21)

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

October 31, 2003

Mr. Melvin C. DeClue, CSP
1201 East Calvert Hill Road
Columbia, MO 65202-7485

Re: Whether U-bolt-type cable clamps are permitted to be used in horizontal lifelines

Dear Mr. DeClue:

This is in response to your letter dated February 4, 2003, to the Occupational Safety and Health Administration (OSHA). You ask for an interpretation of our fall protection standard §1926.502 (fall protection systems criteria and practices) regarding the use of U-bolt-type clamps. We apologize for the delay in providing this response.

We have paraphrased your question as follows:

Question: Scenario: a horizontal lifeline system is used above six feet while performing construction work on a billboard. U-bolts are used at each end of the horizontal lifeline to secure the lifeline to various billboard structures.

I note that in Subpart L (the scaffold standard), §1926.452(x)(9) prohibits the use of U-bolts in fall protection systems on "repair bracket scaffolds." We do not use repair bracket scaffolds. Subpart M, §1926.502, does not seem to have a similar prohibition.

Under Subpart M, is it permissible to use U-bolt-type clamps in the design of a wire rope horizontal lifeline attached to a billboard, with the saddle on the live side of the cable?


Section 1926.450(b) of the scaffold standard defines a repair bracket scaffold as:
a supported scaffold consisting of a platform supported by brackets which are secured in place around the circumference or perimeter of a chimney stack, tank or other supporting structure by one or more wire ropes placed around the supporting structure.
One of the provisions that applies to repair bracket scaffolds is §1926.452(x)(9), which states:
U-bolt wire rope clips shall not be used on any wire rope used to secure brackets or to serve as an anchor for personal fall arrest systems.
The preamble to §1926.452(x)(9) in the August 30, 1996, Federal Register states:
…Where wire rope is used to secure brackets, U-bolt clips shall not be used because a segment of damaged dead end could later become part of the live end due to an increase in the circumference of the structure. By contrast, the standard allows U-bolts in other applications, such as where the U-Bolt is used at the end (dead end) of the wire rope and that part of the wire rope is never moved into the live section… [Emphasis added.]
As explained in the preamble to the scaffold standard, the reason this prohibition was included in the scaffold standard for repair bracket scaffolds was that the U-bolt clips often pinch and decrease the strength of the rope. Since repair bracket scaffolds must be expanded as the work progresses, the pinched (and weakened) part of the wire rope would eventually wind up in the "live end." This, then, was a concern that was specific to repair bracket scaffolds, and therefore the prohibition was included only for that type of scaffold.

As you indicated in your letter, there is no similar restriction on the use of U-bolt clips in Subpart M. As long as the strength and other criteria requirements in §1926.502 for horizontal lifelines are met, the U-bolt clips may be used. When rigged with the saddle side of the clip on the live (loaded) portion of the line, the pinching/damage will typically be limited to the dead end of the rope, and thus not decrease safety.

Note, though, that if you were to reconfigure the system after the clips had damaged part of the wire rope so that the damaged section became part of the "live end" of a horizontal lifeline, it is unlikely that you would be able to meet the strength requirements in §1926.502. Also, under §1926.502(d)(21):
Personal fall arrest systems shall be inspected prior to each use for wear, damage and other deterioration, and defective components shall be removed from service.
If you need additional information, please contact us by fax at: U.S. Department of Labor, OSHA, Directorate of Construction, [Office of Construction Standards and Compliance Guidance], fax # 202-693