As I'm sure you know, scaffolding is used to provide a stable platform for workers to stand on. It's important to try to prevent workers from falling off, so the sides of the platform are extended up and horizontal members are added around the perimeter of the platform and above the platform surface. One rail needs to be at a height that would catch most people a little above the waist, and a second rail is somewhere between that top rail and the platform. Those are the two courses.
Scaffolding more than 5 feet above a solid surface, or at any distance above the water, must be provided with railing which has: [29 CFR 1915.71(j)(1)]
- a top rail of 42 to 45 inches high.
- a midrail located halfway between the top rail and the platform.
Some useful information about specifying scaffolding may be found by visiting the OSHA site: osha.gov. I tried copying a link, but it wouldn't work. Perhaps legalities prevent such actions. OSHA is the US Government group that establishes worker safety rules and guidelines. The rules may be different where you are, but you might find useful terminology. The above in blue is copied from that site.
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