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 http://www.osha.gov.

October 1, 1991 [Reviewed November 8, 2018]

Mr. Michael J. Plank
President
Speed Shore Corporation
7002 Easthaven
Post Office Box 262591
Houston, Texas 77207

Dear Mr. Plank:

This is in response to your July 15 letter in which you request an interpretation from the Occupational Safety and Health Administration (OSHA) concerning the use of Manufacturer's Tabulated Data in the design and application of trench safety systems. We apologize for the delay in responding to your inquiry.

Manufacturer's Tabulated Data that exceeds the limitations of the various tables found in Appendices B thru D of the excavation standard (29 CFR 1926.650 et seq.) may be developed and used in the design and application of trench safety systems provided the development and use are approved by a registered professional engineer. The limitations of OSHA's various tables were formulated on a conservative basis and may be exceeded when the provisions of paragraph 1926.652(c)(2) are met.

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.]