ABSTRACT
Special sections in pipes are valves, tees, wyes, elbows, caps or plugs, transitions such as cones for changes in diameter (i.e. change in flow velocity), and transitions between conduits of differing shapes or sizes such as transitions from a rectangular conduit to a circular pipe. Experience and expertise are available from manufacturers of common standard specials. However pipeline engineers often need an uncommon section. Following are some basic rules and procedures for preliminary design of specials. As an example, consider a wye.
