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Engineer certification for trench protective-system tables

Summary A construction company asked whether trench support and shield systems designed from a manufacturer's tabulated data needed another engineer's certification. OSHA said no: the tabulated data already must be certified by a registered professional engineer under the cited rule. OSHA says it made non-substantive changes to the posted letter in 2018.
Document
Federal opinion letter
Agency
Occupational Safety and Health Administration (OSHA)
Document number
1992-05-21-2
Date issued
May 21, 1992
Status
Active
OSHA says it made non-substantive changes to the letter on November 8, 2018, and that it reflects current regulations and policies.
Status last verified October 9, 2026

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About this page: The full text below is the official document from Occupational Safety and Health Administration (OSHA). Ezel adds the plain-English summary and tracks the document's status. The official source linked on this page is authoritative for any reliance.

May 21, 1992 [Reviewed November 8, 2018]

Mr. Curtis P. Parrish
Vice President of Finance
Wm. G. Knowles Construction Company
[Recipient address omitted]
Dear Mr. Parrish:

This is in response to your April 16 letter requesting an interpretation of an Occupational Safety and Health Administration standard addressing the design of protective systems used in trenches.

You are correct that 29 CFR 1926.652(c), Option (2) allows support systems, shield systems and other protective systems to be designed using manufacturer's tabulated data without additional certification from a registered professional engineer (RPE). Tabulated Data by definition (§1926.650(b)) is required to be certified by a RPE and additional certification is not necessary.

Thank you for your interest in occupational safety and health. We hope you find this information helpful. OSHA requirements are set by statute, standards, and regulations. Our letters of interpretation do not create new or additional requirements but rather explain these requirements and how they apply to particular circumstances. This letter constitutes OSHA's interpretation of the requirements discussed. From time to time, letters are affected when the Agency updates a standard, a legal decision impacts a standard, or changes in technology affect the interpretation. To assure that you are using the correct information and guidance, please consult OSHA's website at https://www.osha.gov. If you have further questions, please feel free to contact the Directorate of Construction at (202) 693-2020.*

Sincerely,
Patricia K. Clark, Director
Directorate of Compliance Programs

*[This letter has been modified (non-substantive changes) on November 8, 2018, and reflects current OSHA regulations and policies.]

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