Pipe Union Vs Pipe Coupling – Meaning, Difference, & Which Is Best

Bathrooms & Utility Rooms, Blog, Plumbing

If you are a plumper or one who frequently engages in DIY plumbing projects, you must have heard of pipe union and pipe coupling. They are both pipe fittings, but they are different and serve specific purposes.

Understanding the difference between the two is very important before commencing any plumbing project. You may even be surprised that one would be a good fit for your project and the other isn’t.

To help you out, I will write about these two pipe fittings, how they differ from each other, and which of them is the right fit for your plumbing project.

What is a pipe union?

union coupling

A pipe union is a pipe fitting used to connect two pipes together without the need of soldering or welding them to one another. It consists of 3 main components; a male end, a female end, and a nut. The two pipes to be connected are inserted into both ends of the union. Afterward, both pipes are secured by tightening the nut with a wrench.

This type of pipe fitting is best for projects that aren’t permanent as it can be dismantled and reassembled easily without damaging any of the pipes.

What is a pipe coupling?

pipe coupling

A pipe coupling, on the other hand, is a short piece of pipe connecting two separate pipe sections. This is done using a variety of methods, which include; soldering, welding, compression, and screwing.

Unlike pipe union, pipe coupling is used for projects that require a more permanent connection. This is mainly because it cannot be removed easily, at least not without the use of special chemicals, which can, in turn, damage the pipe itself.

Pipe union vs pipe coupling – What are the differences between the two?

Although they are both pipe fittings, there are some basic differences between the two. They are;

1. Type of connection

As I have mentioned earlier, both of the two fittings offer a specific connection between two pipe fittings. Pipe coupling offers a permanent bond; once it is used, it is as if both pipes are one.

Pipe union, on the other hand, offers both a permanent and temporary bond between two pipe fittings. If a union pipe is used, you can always disassemble both pipes by losing the nut and reassembling them afterward.

2. Usage

Pipe coupling has restrictions; it is primarily used to connect one pipe to another with a specific diameter. Union coupling, on the other hand, is more versatile. You can connect pipe-to-pipe, as well as pipe-to-other components (e.g., a steam trap, control valve, etc.).

3. Cost

Another difference between these two pipe fittings is cost. Pipe union coupling generally costs more due to its ability to be disassembled and reassembled. Whereas pipe coupling is cheaper because it is more of a one-time usage pipe fitting.

How to choose the right fitting for your project

Now you have a better idea of these two pipe fittings; it’s time to determine which is best for your project. Choosing the right pipe fitting depends on certain factors which I will be highlighting.

1. Location

If you are going to be installing this pipe fitting in a location where you will likely access it again to change or repair it, it is best to go with union coupling.  If it is going to be in a location that will not be easily accessible (like the walls or ceiling), it would be best to go for a more permanent choice, that is, pipe coupling.

2. Budget

You also have to consider your budget for this project. Since pipe coupling is cheaper, it could be the right choice for your project if you have financial constraints. However, you should note that if any repair needs to be done in the future, it might cost you more.


Why is union coupling preferred over pipe coupling?

The main reason for this is that if a repair is needed, it would be easier to dismantle and reassemble the union coupling. With pipe coupling, you will need special chemicals or you will have to cut the pipe and replace it entirely, incurring more cost.

When is pipe coupling used over union coupling?

When the project requires a more permanent fix and is located in a place that cannot be easily accessed.

How do you stop a union coupling from leaking?

There are many ways to fix a union coupling leak. One of the most efficient methods is to wrap the threaded pipe a few times with Teflon tape.

Conclusion – Pipe union vs pipe coupling: Which is a better choice?

Pipe coupling is an inexpensive option for people seeking a more permanent solution. However, you will be limited since they cannot be taken apart once assembled. It is generally believed that a pipe union is a better choice mainly because it is easy to install and can easily be dismantled and reassembled as needed.

That said, the nature of your project may require pipe coupling instead of union. Take into account the nature of your project and your budget when choosing a pipe fitting.

Thank you for reading this article. I hope it was helpful. Before you leave, visit Samkins Construction Lnc for more articles you might find helpful.

About Samkins

Samkins Construction Inc specializes in custom home building, general contracting, design-build, architectural design, construction management, and real estate services.


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