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 30, 2010
Re: (1)Whether #9 wire may be used to secure the toprails and the midrails on tubular scaffolding, and (2) A permissible method for setting transitional wood planks before changing direction on tubular scaffolding utilizing aluminum hook-on planks.
Question #1: Does the OSHA scaffold standard for construction (Part 1926 Subpart L) permit the use of #9 wire to secure the toprails and the midrails on tubular scaffolding?
Title 29 CFR 1926.451 (g)(4) provides the requirements for guardrail systems. Some of the relevant provisions
(vii) Each toprail or equivalent member of a guardrail system shall be capable of withstanding, without
failure, a force applied in any downward or horizontal direction at any point along its top edge of at
least 100 pounds (445 n) for guardrail systems installed on single-point adjustable suspension scaffolds or
two-point adjustable suspension scaffolds, and at least 200 pounds (890 n) for guardrail systems installed
on all other scaffolds.
(viii) When the loads specified in paragraph (g)(4)(vii) of this section are applied in a downward direction,
the top edge shall not drop below the height above the platform surface that is prescribed in paragraph
(g)(4)(ii) of this section.
* * *
(ix) Midrails, screens, mesh, intermediate vertical members, solid panels, and equivalent structural members
of a guardrail system shall be capable of withstanding, without failure, a force applied in any downward or
horizontal direction at any point along the midrail or other member of at least 75 pounds (333 n) for
guardrail systems with a minimum 100 pound toprail capacity, and at least 150 pounds (666 n) for guardrail
systems with a minimum 200 pound toprail capacity.
Employers must ensure that scaffolds are designed, erected and maintained in accordance with the applicable
provisions of Subpart L of Part 1926. Section 1926.45 l(g)(4), which provides requirements for guardrail
systems, does not mandate a particular material to be used for securing the toprails and the midrails on
If the #9 wire results in a guardrail system that meets the capacity and other requirements in Subpart
L, then #9 wire is permissible to secure the toprails and midraiIs on tubular scaffolding. See
paragraph 1(d) of Appendix A to Subpart L for additional guidance.
Question #2: What is a permissible method under Section 1926.451(b)(8) for setting the transitional wood
planks before changing direction on tubular scaffolding utilizing aluminum hook-on planks?
Title 29 CFR 1926.451(b) provides the requirements for scaffold platform construction. Subsection 8
addresses changing the direction of the platform and states:
(8) At all points of a scaffold where the platform changes direction, such as turning a corner, any
platform that rests on a bearer at an angle other than a right angle shall be laid first, and platforms
which rest at right angles over the same bearer shall be laid second, on top of the first platform.
When turning a corner at an angle other than a right angle and using transitional wood planks and aluminum
hook-on planks, section 1926.451(b)(8) requires that the wood planks, which rest on a bearer at an angle
other than a right angle, be laid first and the aluminum hook-on planks, which rest at right angles over
the same bearer, be laid second, on top of the wood planks. This method is not desirable because the hook,
which rests on top of the flat wood plank, creates a tripping hazard.
[Corrected on 09/02/2010]
To avoid creating a tripping hazard, unless the aluminum hook-on plank manufacturer makes hook-on planks at
an angle other than a right angle, a contractor may start the second section flush with the outside of the
first section. This method eliminates the need to use planks at other than a right angle as described in
1926.45l(b)(8), and thus removes the tripping hazard because no layering of planks is necessary to turn
Bill Parsons, Acting Director
Directorate of Construction