Steel flanges provide an easy access for cleaning, inspection or modification. They usually come in round shapes but they can also come in square and rectangular forms. The flanges are joined to each other by bolting and joined to the piping system by welding or threading and are designed to the specific pressure ratings; 150lb, 300lb, 400lb, 600lb, 900lb, 1500lb and 2500lb.

A flange can be a plate for covering or closing the end of a pipe. This is called a blind flange. Thus, flanges are considered to be internal components which are used to support mechanical parts.