The flange is the 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 is 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 application of all these elements to attain a joint, which has acceptable leak tightness.

However, it is not advisable to used flange connection in underground piping when it supposed to be buried.        The flange is also the most common source of leak and fire in a process plant. There are variety of flanges available to suit the requirements. Flanged can be classified in several alternate ways as follows:

Based on Types of Connection

Based on Flange facing Types

Based on Pressure Temperature Ratings

Based on Material Types