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.

January 10, 1994

Mr. Norton S. Beckerman
Utilities Products, Inc.
Three Skyline Place, Suite 1604
5201 Leesburg Pike
Falls Church, VA 22041

Dear Mr. Beckerman:

This is in response to your July 17 letter requesting an interpretation of the Occupational Safety and Health Administration (OSHA) standards addressing soil classification. I apologize for the delay in responding to your inquiry.

Subpart P of 29 CFR 1926 allows an employer four options when selecting or designing a system to protect employees working in excavations. To use option 1, the soil type (A, B, or C) at each excavation must be determined as outlined in Appendix A of Subpart P. The type A, B and C soil classification system is applicable only when designing a system under option 1 (use of the tables contained in appendices C and D.) An employer is not bound by the A, B, and C soil classification if the employer elects to provide a protective system under options 2, 3, or 4.

With regard to your question whether the soil at each excavation must be tested for both type and weight, please be advised that if the employer elects to use option 1, the soil must be assumed to be type C or be tested at every excavation in accordance with Appendix A. If a protective system is designed under options 2, 3, or 4, the employer has the responsibility to make whatever tests are necessary to ascertain all criteria and limitations that a manufacturer or designer (as approved by a registered professional engineer) specifies or recommends regarding the use of the protective system and to assure that the system is used accordingly. This would include a determination that the limitations of the system are not exceeded by the soil at each excavation.

With regard to your question whether C60 soil can be considered a worse case scenario, please be advised that OSHA does not regard the C60 classification as including the "worst" type of soil. If, therefore, a manufacturer's tabulated data covers soil only through the C60 classification, then the data does not cover all possible soil types. An employer who elects for convenience sake to treat the soil in an excavation as C60 would still have a duty to ascertain that the soil is not in fact worse than C60.

If we can of any further assistance, please contact me or Mr. Dale R. Cavanaugh of my staff at (202) 219-8136.


Roy F. Gurnham, P.E., J.D.
Directorate of Compliance Programs

July 17, 1993

Mr. Roy Gurnham, Director
Office of Construction Compliance
Room N3610
Occupational Safety and Health Administration
United States Department of Labor
200 Constitution Avenue
Washington, D.C. 20210

Re: 29 CFR Part 1926 Excavation Standards

Dear Mr. Gurnham:

We are bidding on protective shields and shoring for job in a number of States under the Federal OSHA Program or which have their own OSHA-approved program. So that we may accurately comply with your requirements we need clarification on issues regarding soil classification.

We understand the requirements for testing soil to establish their classification as Type A, B or C as defined in 29 CFR 1926 Subpart P. The confusion comes in with the soil designation C60. As we understand it Type C60 soil is a classification that falls between Type B and Type C soils, as defined in Subpart P, and weighs 60 lbs. per vertical foot. This is 20 lbs. less than Type C soil as defined in Subpart P.

The question is this, "If the Manufacturers Tabulated Data for our shoring system shows a Certification for depths based on C60 soil, do we have to test the soil for both type and weight at each excavation or can we assume that C60 is a worst case scenario?"

Since our bidding responses have time deadlines, your prompt attention and immediate reply to this question would be greatly appreciated.


Norton S. Beckerman