A pipe support or pipe hanger is a designed element that transfers the load from the Pipe to the supporting structures. The load includes the weight of pipe proper, the content the pipe carries, all the pipe fittings attached to pipe & the pipe covering such as insulation.
A Dummy Pipe Support is an extension piece welded to an elbow in order to support a pipe line, and rests or anchors on some steel member.
Pipe size, length and wall thickness of the pipe-extension depends on several factors such as the total load, the parent pipe line size etc