What are barrel unions?

What are barrel unions?

A PVC Pressure Barrel Union is used to break the line and allow access for maintenance. The locking nut can be unscrewed to allow a section of pipe or a fitting to be removed. Often a barrel union is used in front of a check valve or a pump to isolate it and to have the ability to break the line.

What is Union joint?

a detachable joint, formed by means of a union, that is used to connect the parts of a piping system to various tanks or machines. Besides a union, a union joint consists of a gasket, a locknut, and a reducer, such as an elbow or a coupling (Figure 1).

What is the difference between a coupling and a union?

But there is a difference between a coupling and a union in terms of black and galvanized pipe. A coupling is a solid fitting with female threads on the inside of both ends. A union is used when you are trying to join two pipes together that are fixed, thus unable to be turned.

What is the correct way to install a pipe union?

Thread the male half of the union nut onto the left-side pipe, and tighten it securely. Slip the ring nut portion of the union onto the right-side pipe with the threads facing outward. Thread on the other half of the union nut, and tighten it securely.

Where are pipe unions used?

Pipe unions are used in various municipal and industrial applications like as follows:

• Fire protection.
• Process piping system.
• Water and wastewater etc.

What is the male side of a pipe union?

Male threads are on the outside, like a bolt. Female threads are on the inside, like a nut. The male threads screw into the female threads. This sometimes leads to confusion when dealing with hard brake lines and other rigid tubing. These pipes usually have a male-threaded nut at the end.

Can you use a union in a gas line?

Any union in a gas line must have a valve in front of it. Blue stuff might be Megaloc Teflon Thread Sealant. Companion flanges are code approved when dealing with two points of piping where you cannot gain access to the opposite end of piping.

Do you use Teflon tape on unions?

Don’t use teflon tape on union threads. For copper unions you can grease the threads and mating faces with vaseline or use pipe dope. tests good. The pipes going into the unions need a pipe thread sealer.

How much length does a pipe union add?

The distance between the fittings and the extra reach must be included in the length. If you are using 1/2 inch pipe, add 7/16 inch per end and 1/2 inch per end.