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.



August 1, 2000

Mark Troxell, Director of Safety
The Graham Company
107 Ponderosa Drive
Blandon, PA 19510

Re: 29 CFR 1926.501(b)(10) Roofing work and other trades working on low slope roofs

Dear Mr. Troxell:

This responds to your July 19, 1999 letter to the Occupational Safety and Health Administration (OSHA) requesting clarification on the use of fall protection for employees, other than roofers, working on low slope roofs. We apologize for the long delay in providing this response.

In your letter you state that other trades (for example, electricians and mechanical trades), when working on roofs, tie-off only when they go outside the warning line system. You specifically ask if that type of procedure is acceptable to OSHA.

OSHA's fall protection standard for construction, 29 CFR 1926 Subpart M (beginning at §1926.500), generally requires fall protection when there is a fall distance of 6 feet or more. In a few, very specific situations (low-slope roof work, some leading edge work, precast concrete erection and residential construction), because of feasibility limitations, the standard permits the use of a warning line, in combination with other measures, instead of conventional fall protection (guardrail systems, personal fall arrest systems or safety net systems) to keep employees away from an edge.

Section 1926.501(b)(10) allows roofers working on low-sloped roofs to have several fall protection options. Under that section an employer may use a combination of warning lines 6 feet (and in some cases 10 feet) back from the edge in combination with monitors in place of personal fall protection equipment or guardrails. OSHA recognized that guardrail systems, safety net systems and personal fall arrest systems could pose feasibility problems during roofing work; therefore, the rule allows other choices of fall protection methods.

Under paragraph 1926.501(b)(2), 1926.501(b)(12), and 1926.501(b)(13), employers engaged in other specified work, such as leading edge work, precast concrete erection, and residential construction may develop and implement a site specific fall protection plan that uses alternative fall protection methods if they can demonstrate infeasibility of conventional fall protection. In some cases warning lines may be used under these provisions.

The terms of the standard do not otherwise provide that warning lines may be used in place of conventional fall protection. However, we have now had six years of experience with the application of Subpart M since it was published in 1994. As we explained in a letter to Mr. Barry Cole last year, we have determined that in the areas further back from the distances specified for the warning lines permitted under the standard, there is a point that is sufficiently far from the edge to warrant the application of a de minimis policy regarding non-conforming guardrails.

Your letter states that the warning line system is "around the perimeter of the roof." At 15 feet from the edge, a warning line, combined with effective work rules, can be expected to prevent workers from going past the line and approaching the edge. Also, at that distance, the failure of a barrier to restrain a worker from unintentionally crossing it would not place the worker in immediate risk of falling off the edge. Therefore, we will apply a de minimis policy for non-conforming guardrails 15 or more feet from the edge under certain circumstances. Specifically, we will consider the use of certain physical barriers that fail to meet the criteria for a guardrail a de minimis violation of the guardrail criteria in §1926.502(b) where all of the following are met:



  1. A warning line is used 15 feet or more from the edge;
  2. The warning line meets or exceeds the requirements in §1926.502(f)(2);
  3. No work or work-related activity is to take place in the area between the warning line and the edge; and
  4. The employer effectively implements a work rule prohibiting the employees from going past the warning line.



In sum, the use of warning lines closer than 15 feet from the edge is not permitted as a substitute for conventional fall protection for these other trades. Furthermore, when these other trades use a warning line system in accordance with the policy described above, the workers must use conventional fall protection when they are outside the protection of the warning line system.

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 Guidance, fax # 202-693-1689. You can also contact us by mail at the above office, Room N3468, 200 Constitution Avenue, N.W., Washington, D.C. 20210, although there will be a delay in our receiving correspondence by mail.


Russell B. Swanson, Director
Directorate of Construction

[Corrected 6/2/2005]