In addition, the platform is supported by, and attached to, a grid of horizontal (and vertical) cables. 4 However, in under-slung bridge scaffolds of the type you have described, the platform is made of long sections of interlocking decking material. 451(f)(16) applicable to this type of scaffold system if the platform is made of a flexible material?Īs discussed in Question 1, §1926.451(f)(16) was promulgated based on the use of rigid-type platforms used in traditional scaffolding designs. However, for reasons described to the answer below to Question 2, the failure to meet the §1926.451(f)(16) requirement for non-wood platforms used in this type of scaffold system would be, in certain circumstances, a de minimis violation. ![]() ![]() In light of the purpose of 1926.451(f)(16), "span" in this context refers to the distance between the horizontal cables. In the case of the Platform System, the horizontal cables slung beneath the steel platform material are the equivalent of horizontal bearers in a supported scaffold. In a two-point suspension scaffold, the span would be the distance between the points at which the cables attach to the platform structure. 2 In a supported scaffold, the span would be the distance between the scaffold framing members that hold up the platform (or, where there is a cantilever, the distance from the last point of support). In construction scaffolds, the word span typically refers to the length of a rigid-type scaffold platform, measured between the structural supports. In addition, when the deflection exceeds the provision's requirement, there is a greater likelihood of a platform's ends pulling away from the supports. Section 1926.451(f)(16) is intended to serve as a visual benchmark of the safe structural limits of the platform. is intended to limit the amount platform units can deflect under load without becoming overstressed and without their ends being pulled from their supports. The preamble for Subpart L states that: Final rule paragraph (f)(16) provides that platform units shall not deflect more than 1/60 of the span when loaded. This provision was drafted to address specific hazards present in traditional scaffold platforms, which typically are made of wood planks or are fabricated, rigid units. ![]() Section 1926.450 does not define the term "span," nor does it specify a method for calculating the span. 451(f)(16) states: Platforms shall not deflect more than 1/60 of the span when loaded. We have illustrated the scenario you describe, as we understand it, as follows: In the context of this type of system, what does "the span" refer to? 451(f)(16) Subpart L "Scaffolds" requires that a scaffold platform not deflect more than 1/60 of the span when loaded. The rigid platform deck, which is made of steel, is supported by cables slung beneath it. ![]() The Platform System is suspended from the underside of the bridge by cables. Question (1): We manufacture the Safespan Multi-Span Bridge Platform System ("Platform System"), which is used to form a temporary work surface for work beneath a bridge. We have paraphrased your questions as follows: We apologize for the delay in responding. This is in response to your letter dated July 14, 2003, to the Occupational Safety and Health Administration (OSHA), asking for clarification on OSHA's construction industry standards as applied to under-bridge type scaffold platform systems. Re: Composition, span, and deflection of underslung bridge scaffold platform systems §1926.451(f)(16)
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