The flange is second most used joining method after welding. Flanges are used when joints need dismantling. It provides flexibility for maintenance. Flange connects the pipe with various equipment and valves. Breakup flanges are added in the pipeline system if regular maintenance in required during plant operation.
A flanged joint is composed of three separate and independent although interrelated components; the flanges, the gaskets, and the bolting; which are assembled by yet another influence, the fitter. Special controls are required in the selection and applicationof all these elements to attain a joint, which has acceptable leak tightness.