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.

June 15, 1993

Mr. Eddie Olsen
Brand Scaffold Services, Inc.
P.O. Box 130
Sulphur, LA 70664

Dear Mr. Olsen:

This is in response to your March 23 letter requesting an interpretation of the Occupational Safety and Health Administration (OSHA) standards addressing the strength of scaffold planking. I apologize for the delay in responding to your inquiry.

With regard to what constitutes full-thickness, undressed lumber, please be advised that full thickness is defined by the current grading rules for the species of wood used. However, anything less than that specified in the applicable 1971 definition (several grading rules have changed since 1971) would need to have the corresponding "loads allowed" reevaluated for the spans involved.

As discussed in your March 1 telephone conversation with Mr. Dale Cavanaugh, OSHA will accept a registered professional engineer certification that planking meets the full thickness undressed lumber strength requirements in Table L-3 of 1926.451(a)(10).

As recognized by the Notice of Proposed Rulemaking for Subpart L--Scaffolds, issued November 25, 1986 (51 FR 42680), design of a scaffold system by a registered professional engineer is acceptable provided the capacity criteria of paragraph .451(a) and the use criteria of .451(d)(14) of the proposal are met. A copy of these provisions is enclosed.

These proposed provisions have not yet been finalized and the rules you are familiar with are still in effect. However, in this matter, a violation of the existing rules will be considered by OSHA to be "de minimis" provided the proposed rules are followed. A "de minimis" violation is one which has no direct or immediate relationship to employee safety health.

If we can be of any further assistance please contact me or Mr. Dale Cavanaugh of my staff at (202) 219-8124.


Roy F. Gurnham, P.E., Esq.
Office of Construction and Maritime
Compliance Assistance


March 23, 1993

U.S. Department of Labor
200 Constitution Ave., N.W.
Washington, D.C. 20210

Attn: Bill Cavanaugh

Dear Mr. Cavanaugh,

This letter is in conjunction with our telephone conversation the week of March 1, 1993.

I called you to get a clarification on O.S.H.A. regulation 1926.451(a)(10), Table L-3.

In essence, my question was "What constitutes full-thickness, undressed lumber?"

Our current inventory of undressed lumber ranges from 1 5/8" to 2" in thickness, and 9 1/2" to 10" in width.

In our conversation, you indicated that the thickness could vary up to 1/4" and still be considered full-thickness lumber. You also indicated that our boards which are 1 5/8" in thickness would be in compliance if we had engineering approval that these boards meet the strength requirements of "full thickness, undressed" lumber as set forth in table L-3.

I would like to take time to thank you and also Mr. Jose Chapa from you Dallas, Texas office for your prompt response by telephone.

I would also like to request your written response to the above mentioned clarification so that I may have this information on file for future reference.

You may mail the response to the following address:

Brand Scaffold Services, Inc.
P.O. Box 130
Sulphur, LA 70664
Attn: Eddie Olsen

If you have any questions, please feel free to call me at (318) 625-3541.

Thank you,

Eddie Olsen
Division Manager