Around the time that OSHA came out in the early 70's, somebody spent a lot of time and mental energy in developing a prescriptive design table for Tube-and-Clamp, that if followed in accordance with all the requirements of OSHA, allowed a contractor to erect a scaffold 125 feet high without requiring the services of an engineer. Subsequently, someone had the idea that if you can build a scaffold 125 feet high in Tube-and-Clamp, there's no reason why you couldn't do the same with Frames. I don't agree. There are no restrictions on Frames as there are in the Tube-and-Clamp prescriptive design. John Rosenthal, P.Eng. FEC