Engineer approval for an added soil classification

October 1, 1991 [Reviewed November 8, 2018]

Mr. Regis M. Hallisey
General Manager
The Plank Company
[Recipient address omitted]

Dear Mr. Hallisey:

This is in response to your July 24 letter in which you request an interpretation from the Occupational Safety and Health Administration (OSHA) concerning the use of Manufacturer's Tabulated Data as it applies to the C-60 soil classification. We apologize for the delay in responding to your inquiry.

In response to your question whether the C-60 soil classification is an acceptable addition to the classifications set forth in the excavation standards (29 CFR 1926.650 et seq.), please be advised as follows: Option (2) - Designs Using Manufacturer's Tabulated Data, set forth in 1926.652(c)(2), allows the use of tables other than those given in the OSHA standards. However, by definition, "tabulated data" means "tables and charts approved by a registered professional engineer and used to design and construct a protective system" (emphasis added). (See 29 CFR 1926.650 definitions.)* Therefore, the C-60 soil classification you submitted may be used in the design of protective systems if the classification and subsequent designs have been approved by a registered professional engineer.

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.]