Boltex Reference Manual
About Flanges
The dictionary defines flange as a projecting rim or collar on a wheel, pipe, rail, etc. For the products described in this catalog, a flange is a forged ring of steel designed to join two sections of a piping system or start a piping system from a pressure vessel, valve or any other integrally flanged assembly. It may be joined to the piping system by threading or welding. Flanges are joined to each other by bolting.
For example, every pressure vessel has at least one outlet which is flanged to allow connection of a piping system. In the flange is a predetermined bolt circle and number of holes. Certain flanges are designed with the same bolt circle and bolt holes so the two can be mated together. From the mating flange, the piping system can be started.
Flanges are designed according to pressure and temperature requirements as established by ASME Code or in accordance with specific customer requirements. Flange diameter and thickness will normally increase as the pressure rating increases.
