A MS union is a type of pipe fitting that creates a secure and semi-permanent connection between two pipes. The pipes can easily be separated without causing any piping deformation. Pipe union connections are mostly used for small bore pipe connections. Whenever an easy assembly and disassembly along with a positive sealing is required, pipe union fittings are used. Common pipe unions are usually manufactured in a size range from 1/8 inches to 4 inches.

Parts of a Pipe Union Fitting

A pipe union has three parts; a male end, a female end, and a nut. The male and female ends of the piping union are sealed together in the nut. The female end has threads on the inside surface whereas the male end has threads on the outside surface. The nut provides the required sealing pressure to the union joint. The threaded pipe union is threaded to be NPT per ASME B1.20.1 whereas the nut is straight thread as per ASME B1.1. The seating surfaces of the joint shall be integral metal-to-metal, ball-to-cone design. Socket welding (SW) is used for welding pipes and fittings including reducers, tees and elbows. Socket weld pipe fittings are used to permanently join pipes that are inserted into a recess in the fitting, flange or valve. Once correctly inserted, fillet type sealing welds are applied to join the pipe to the fitting. These fittings are commonly known as SW pipe fittings, with SW couplings, SW elbows and SW tees being examples of different types. Socket welds can be used to change the direction of travel for pipe networks as well as join pipes at different angles and of different diameters. The high leakage integrity and structural strength of socket welds allow them to be used for a range of piping network applications. For other types of IBR Certified Fittings, click here.