Pipe fittings are accessories which are used to connect pipes, including with elbows, tees, reducers, caps, flanges, etc. The function of pipe fittings are connection, control, turning, shunt, sealing, supports etc.  

There are two international systems for the pipe fittings, one is DIN standard representing the European pipe fittings systems, and another is ANSI representing the American pipe fitting systems. ANSI mainly including ANSI 16.5 and ANSI B16.47.