A flange is a method of connecting pipes, valves, pumps and other equipment to form a piping system. It also provides easy access for cleaning, inspection or modification. Flanges are usually welded or screwed. Flanged joints are made by bolting together two flanges with a gasket between them to provide a seal.
Types of Flange:
Welding Neck Flange, Slip On Flange, Socket Weld Flange, Lap Joint Flange, Threaded Flange, Blind Flange.
A pipe fitting is defined as a part used in a piping system, for changing direction, branching or for change of pipe diameter, and which is mechanically joined to the system. There are many different types of fittings and they are the same in all sizes and schedules as the pipe.
Fittings are divided into three groups:
Butt-weld (BW) fittings whose dimensions, dimensional tolerances et cetera are defined in the ASME B16.9 standards. Light-weight corrosion resistant fittings are made to MSS SP43.
Socket Weld (SW) fittings Class 3000, 6000, 9000 are defined in the
ASME B16.11 standards.
Threaded (THD), screwed fittings Class 2000, 3000, 6000 are defined
in the ASME B16.11 standards.