Archive Notice - OSHA Archive

NOTICE: This is an OSHA Archive Document, and may no longer represent OSHA Policy. It is presented here as historical content, for research and review purposes only.

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

July 3, 2001



Director,Region VIII
Director, Directorate of Construction
SUBJECT: STD 3-0.1A Height Limitations for Walking the Top While Installing Trusses and Rafters


This memorandum responds to your June 14 e-mail to Noah Connell in which you ask for a clarification of the height restrictions found in STD 3-0.1A, the plain language rewrite of OSHA Instruction STD 3.1, titled Interim Fall Protection Compliance Guidelines for Residential Construction. You describe a situation in which an employer is framing a 3-story stick built apartment building where the roof's peak is 46 feet and the ground-to-eave height is 30 feet. You question whether employees installing roof trusses or rafters are permitted to walk the top plate at heights greater than 25 feet without conventional fall protection.

According to the information you submitted, the activity on the structure you describe would be covered by STD 3-0.1A.

As you know, STD 3-0.1A did not change any pre-existing policies; however, the rewrite better organizes the alternative fall protection procedures into four groups of activities, which are now conveniently located in one document. Installing roof trusses is a Group I activity, as taken from Appendix E of the fall protection standard, §1926.500.

Group I states in part:



NOTE: Height Limitation: The Appendix E plan may only be used on structures up to three and a half stories or 48 feet (including basement, two finished levels, attic). The 48' measure is from the base of the building, at the lowest ground level (including any excavation), to the point of greatest height.

This note helps to define the scope of structures covered by STD 3-0.1A. An employer has to determine if the structure being built is within the scope of STD 3-0.1A before using the alternative fall protection methods it prescribes for specific residential construction activities. The first sentence of the note makes it clear that the height limitation is based on the height of the structure: "The Appendix E plan may only be used on structures up to three and a half stories or 48 feet . . . ." Therefore, the "point of greatest height" referred to in the second sentence refers to the height of the structure. This provision is a criterion for all structures that fall within the definition of residential construction.

The 25-foot eave-to-ground height limitation you refer to in your e-mail is a requirement in Group IV, roofing work. This height limitation was established for roofing work in the original STD 3.1. The height limitations for Group IV activities are recognizably more stringent but do not apply to Group I activities. The two sets of requirements were established at different times, in two entirely different documents, for only the activities they specifically identify and were only brought together in STD 3-0.1A for better organization.

In addition, OSHA clarified its policy on STD 3-0.1A with regard to apartment buildings in an April 24, 1998, interpretation letter to Susan R. Noyes and a May 25, 2000, memorandum to John B. Miles. In these interpretations, OSHA explains that apartment complexes built with the same materials and methods as traditionally used in wood framed single family houses and townhouses would be considered residential.

Please feel free to contact us if you need further clarification on this issue.