We focused on the toprail requirements of a supported scaffold in the last Spotting Safety article, so let’s look at where the scaffold meets the ground to see why this photo, of wood blocks shimmed underneath a scaffold leg, doesn’t meet OSHA regulations.
- “Unstable objects shall not be used to support scaffolds or platform units.” 1926.451(c)(2)(ii)
OSHA defines unstable objects as items whose strength, configuration, or lack of stability may allow them to become dislocated and shift. Examples include: barrels, boxes, loose brick, and concrete blocks.
It’s too easy to imagine the scaffold moving just enough to cause the pole to slide off the top block. Or one of the blocks could just as easily get kicked out of the pile.
An adjustable screw jack on the bottom of this pole would provide a solid base with the concrete and allow a worker to dial in exactly the right height to ensure a level scaffold.
Speaking of which, the other bare pole can present its own problems.
- “Supported scaffold poles, legs, posts, frames, and uprights shall bear on base plates and mud sills or other adequate firm foundation.” 1926.451(c)(2)
Attaching a metal base plate footing to the bottom of all scaffold frames is an easy way to ensure a sound foundation. In truth, base plates are not always necessary as long as the foundation is firm enough, and concrete is the one material that OSHA says doesn’t need to be evaluated by a competent person.
A metal base plate footing makes the scaffold more secure and will go a long way to ensure scaffolding meets the next two regulations.
- “Footings shall be level, sound, rigid, and capable of supporting the loaded scaffold without settling or displacement.” 1926.451(c)(2)(i)
Although not an issue in this photo, this means that if the scaffold settles into the ground even with footings, then additional measures, such as mudsills may be necessary. It is up to the competent person, appointed by the business to make these decisions.
- “Supported scaffold poles, legs, posts, frames, and uprights shall be plumb and braced to prevent swaying and displacement.” 1926.451(c)(3)
This regulation speaks to the competent person identifying all necessary ties, guys, braces, and outriggers to make sure a scaffold doesn’t tip, but also requires attention to the scaffold’s poles, legs, post frames, and uprights to ensure they will stay braced and plumb so they don’t sway or move.
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