Full and Half Couplings

Full coupling is used for making branch connections. How this is possible ?
A lot of time and energy is spent grinding one end to fit against the header pipe and then the edge (of the same end) must be ground to form a bevel required for the full penetration weld. This is very costly and is better done with a "Sock-O-Let" or a "Thread-O-Let"

Also tell about half coupling & its usages in piping.
In all my years (45+) I do not remember using a half coupling. I recommend that you forget that they exist.

The suggested above is correct; secondly half coupling we use for air headers i.e distribution headers where only one threaded end was required and projection height required are minimal; the other end is welded to the main pipe. This was done when low pressure and partiuclar mateiral requirement was there.

hello, half couplings are used instead of Soc o lets or thread o lets on lower pressure pipe lines. The work very well on Sch. 10 stainless steel pipe because they will pull or warp the branch allot less than welding an o let. I would not recommend using a half coupling on piping that is over 150 psi or on a steam line though. Full couplings are used to join 2 pieces of pipe and they can be cut in half to make 2 half couplings very easy. I usually do this because it saves money and serves the same purpose. Half couplings are used intensively on fire protections systems, air and water lines and many different lower pressure process lines.

I used to manufacture various tanks for some of the systems I produced. I would use half couplings on the walls of the tank where a pipe is to be installed. The flat end of the half coupling would be welded to the flat tank wall and the pipe would then be threaded into the threaded end of the half coupling.

If one were doing a lot of these type of installations, the full coupling, as stated by others, could be cut in half and the result would be two half couplings that could be used. The weld-o-let type fittings are usually curved at the weld-on end such that they closely fit the OD of the pipe to which they are welded. For that reason, they would not lend themselves well to being welded on a flat tank surface.

There were times when it was required that a pipe enter the tank and then connect to other piping within the interior of the tank. In those instances, I would cut the hole in the tank to match the OD of the full couping and put the full coupling through the hole and weld around it so there would be a threded connection both inside the tank and outside.

I would take this one step further and introduce a cautionary note regarding standard required markings, and material traceability in situations where it is required (such as the ASME vessel construction standards, or piping standards). The ANSI / ASME B16.11 required markings are normally not found on both ends of a full coupling.

Dan W.

The half coupling and/or full coupling can be welded as a branch to the main run and welded as "put in" or "put on". Only in case of full coupling, there is some protrude inside the pipe/vessel as it is allowed.

Stainless Steel Threaded Half Coupling & Stainless Steel Half Socket Coupling

Half Coupling (Socket Weld Pipe Fitting, Precision Pipe Fitting)

Class 9000 Socketweld Half Coupling