Reducing
flanges are designed for use in changing diameters in a piping system. A
reducing flange comprises a flange with one specified diameter having a
bore of a different and smaller, diameter. Except for the bore and hub
dimensions, the reducing flange will have dimensions of the larger pipe
size. These flanges are used at the outlet side of the expansion joint
to increase the size of the flange. This is considered to be an
economical method to make a transition in size.