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.

April 11, 2005

Mr. Douglas A. Holman
1816 River Bend Road
Sevierville, TN 37876

Re: Whether 2"-x-6" No. 2 pine boards may be used as a scaffold platform; whether §1926.451(a) and §1926.451(f)(16) are applicable when erecting and dismantling scaffolds.

Dear Mr. Holman:

You have submitted nine letters to the Occupational Safety and Health Administration (OSHA) containing a number of questions on the construction scaffold standard (29 CFR Part 1926 Subpart L).
1 We are responding in a series of separate letters in response; this is the third in that series.

We have paraphrased your questions regarding use of 2"-x-6" No. 2 pine boards as a scaffold platform and the applicability of §1926.451(a) and §1926.451(f)(16) when erecting and dismantling scaffolds as follows:

Question 1a: Scenario: A scaffold has a 5'-x-7' frame that is decked with a 4-foot wide (5/8-inch thick) plywood sheet supported by three 2"-x-6" boards. Viewed from beneath the platform, the configuration looks like this:


Depiction of scaffold platform frame decked with plywood sheet and three support boards; illustration shows scaffold dimensions

The contractor has determined that based upon the anticipated load, the scaffold will meet the 4:1 capacity requirement in Subpart L. Section 1926.451(b)(1) limits the permissible gap between the platform and the uprights to 9½ inches or less. In this case, the gap is 12 inches.

My first question relates to whether it is permissible to use 2"-x-6" No. 2 pine planking to fill this gap. I note that none of the technical resources referred to in Non-Mandatory Appendix A lists 2"-x-6" No.2 pine as scaffold grade planking.

Answer: Section 1926.451(a) (Capacity) requires that:



* * * * *
(6) Scaffolds shall be designed by a qualified person and shall be constructed and loaded in accordance with that design. Non-mandatory Appendix A to this subpart contains examples of criteria that will enable an employer to comply with paragraph (a). [Emphasis added.]
* * * * *

Section 1926.451(b)(1) addresses the size of scaffold platforms:

Each platform on all working levels of scaffolds shall be fully planked or decked between the front uprights and the guardrail supports as follows:
(i) Each platform unit (e.g., scaffold plank, fabricated plank, fabricated deck, or fabricated platform) shall be installed so that the space between adjacent units and the space between the platform and the uprights is not more than 1 inch (2.5 cm) wide, except where the employer can demonstrate that a wider space is necessary (for example, to fit around uprights when side brackets are used to extend the width of the platform).
(ii)Where the employer makes the demonstration provided for in paragraph (b)(1)(i) of this section, the platform shall be planked or decked as fully as possible and the remaining open space between the platform and the uprights shall not exceed 9½ inches (24.1 cm).
* * * * *

"Platform" is defined in §1926.450(a) as:

... a work surface elevated above lower levels. Platforms can be constructed using individual wood planks, fabricated planks, fabricated decks, and fabricated platforms. [Emphasis added.]

Employers must ensure that scaffolds are designed, erected, and maintained in accordance with the applicable provisions of Subpart L.2

Although Subpart L does prescribe specific dimensions for platforms in limited instances,3 generally the specific dimensions (thickness and width) of the planks or the other material used to build a platform are left to the discretion of the qualified person so long as the design requirements of Subpart L are satisfied.

Further, the lack of reference to 2"-x-6" No. 2 pine planking in the Non-Mandatory Appendix A does not preclude its use, in that the appendix is only intended "to assist employers in complying" with Subpart L. As stated in that appendix:

... components for which no specific guidelines or tables are given in this appendix (e.g., joints, ties ... components made with other materials, and components with other dimensions, etc.) must be designed and constructed in accordance with the capacity requirements of §1926.451(a) ... [Emphasis added.]

In addition, with respect to your reference to the term "scaffold grade," note that we have previously explained that Subpart L does not require that planking be marked as "scaffold grade." See our February 16, 2001, letter to Mr. Robert Harrell and our March 12, 2002, letter to Wood Advisory Services, Inc.4

Thus, in this scenario, 2"-x-6" No. 2 pine planks (or other materials) are permitted to be used as long as they conform to the requirements in the standard. As indicated above, the qualified person's design must comply with the applicable provisions of Subpart L.

Question 1b: In the previously described scenario, I am concerned about scaffold erectors standing on a 2"-x-6" plank in the process of assembling the scaffold platform. Do the capacity and deflection criteria set forth in §1926.451(a) and §1926.451(f)(16), respectively, apply during the erection process?

Answer: Section 1926.451(a) requires:

... each scaffold component shall be capable of supporting, without failure, its own weight and at least 4 times the maximum intended load applied or transmitted to it.

As stated above in §1926.451(a)(6), the scaffold must be designed by a qualified person and constructed in accordance with that design.

Section 1926.451(f)(16) provides:

Platforms shall not deflect more than 1/60 of the span when loaded.

Finally, §1926.451(f)(7), which specifically applies to the erection/dismantling process, provides:

Scaffolds shall be erected, moved, dismantled, or altered only under the supervision and direction of a competent person qualified in scaffold erection, moving, dismantling or alteration. Such activities shall be performed only by experienced and trained employees selected for such work by the competent person.

In the preamble to the final rule, in discussing §1926.451(f)(7), OSHA stated:

The Agency has also clarified that the actual work be performed by experienced and trained employees, selected by the competent person. This change is based on an ACCSH recommendation (Tr. 88-92, 6-9-87). In particular, a member of the Advisory Committee stated "it needs to be employees that are properly trained and experienced being the only ones allowed to do this kind of work." OSHA agrees with this recommendation because, unlike other individuals on a finished scaffold, erectors and disassemblers are exposed to the hazards of working on a partially completed structure, and a competent person is needed to select the proper individuals to do this work. [Emphasis added.]

This demonstrates that the Agency contemplated that the erectors and dismantlers would be on the scaffold when doing this work. Since the scaffold necessarily will be incomplete during this process, it was anticipated that full compliance with all design requirements would not be always be feasible. The Agency in effect acknowledged that this would be the case by requiring that the work "be performed only by experienced and trained employees selected for such work by the competent person" and that the work be supervised and directed by "a competent person qualified in scaffold erection, moving, dismantling or alteration."

Implicit in the §1926.451(f)(7) provision is a requirement that the competent person direct the erecting and dismantling work in a manner that ensures the safety of the workers to the extent that is feasible.
5 Therefore, the employer is required to have the competent person direct the work so that, to the extent feasible, the design requirements are met during the erecting and dismantling process.

Consequently, we cannot say as a general matter that, in all cases and at all times throughout the erecting and dismantling process, the capacity and deflection requirements must be met. Rather, under the direction and supervision of the competent person, they must be met to the extent feasible.

If you need additional information, please contact us by fax at: U.S. Department of Labor, OSHA, Directorate of Construction, Office of Construction Standards and Guidance, fax # 202-693-1689. You can also contact us by mail at the above office, Room N3468, 200 Constitution Avenue, N.W., Washington, D.C. 20210, although there will be a delay in our receiving correspondence by mail.


Russell B. Swanson, Director
Directorate of Construction

1 When we originally received these questions from you in April 2003, it was unclear to us if you were requesting a response to each or if they were submitted only to call our attention to these issues in the event that OSHA were to do further rulemaking on the standard. We attempted to resolve that with you but we were unable to obtain a response; consequently, our office closed the file. After your communications with my staff on January 13, 2005, we understand now that you are requesting a response to each question. We apologize for the misunderstanding and resulting delay in providing this response. [ back to text ]

2 One of these requirements is §(b)(1), which limits the permissible gap between the platform and the uprights to 9½ inches or less. [ back to text ]

3 See, for example, §1926.451(b)(2). [ back to text ]

4 You state that, in the scenario you describe, a worker standing on a 2x6-inch No. 2 pine plank would "certainly cause [it] to deflect more than 1/60 of its span" and therefore be in violation of §1926.451(f)(16). We do not have the resources to ascertain the deflection characteristics of such a board and therefore decline to comment on that assertion. [ back to text ]

5 Furthermore, part of the standard's definition of competent person (in §1926.450(b)) is that he/she have "authorization to take prompt corrective measures to eliminate [hazards]." [ back to text ]