Pipe Union Fitting | 7 Types of Union and Installation

Pipe union fittings is a plumbing system. It makes plumbing easy for connecting and disconnecting pipes without using complicated tools or extensive pipe cutting.

Pipes are generally made up of metals like brass, stainless steel, or galvanized iron. In some cases, plastics like ABS or PVC are also used to make pipes for union fittings.

These union fittings come in a wide range of sizes to accommodate various pipe diameters. Two different styles of pipe union fittings are available, that is threaded and slip-on. Threaded fittings need to be tightened with a wrench while Slip-on fittings are installed by hand.

Union fitting is used for Plumbing, HVAC, irrigation, fire sprinkler systems, industrial applications, etc.

How to Choose Pipe union fitting?

a) Material: The materials used in the pipe fitting must be appropriate for the type of pipe that is being used.

b) Size: The diameter of the pipes must match the size of the pipe union fitting to be joined.

The type of union fitting should be selected on the ease of installation and the desired level of security, whether that is threaded or slip-on.

Tips for installing pipe union fittings

Pipe fitting is a flexible and dependable method. They provide a reliable, leak-free connection and are simple to install. For best results, while selecting union fittings the material, size, type, and application should be observed carefully.

  • The pipe must be clean and free of debris before installing this union fitting.
  • Apply thread sealant: Thread sealant should be applied to the threads of the pipe union fitting for preventing leakage.
  • Fitting, tighten it. The pipe union fitting should be tightened firmly and not too tightly.
  • To check joints for leaks, running water through the system should be used.

Types of Pipe union fitting

  1. Black pipe union fitting
  2. CPVC pipe fitting
  3. Galvanized pipe union fitting
  4. Hydraulic union pipe fitting
  5. Male union pipe fitting
  6. Stainless union pipe fitting
  7. ABS union pipe fitting

1) Black Pipe Union Fittings

Pipe Union Fitting | 7 Types of Union and Installation

Black malleable iron is used to make black pipe union fittings. They are often used in gas supply lines. Due to their high durability and resistance to corrosion, they are excellent for outdoor applications.

The halves of these fittings are simply screwed together or opened with the help of a wrench. The threaded design gives guarantee a tight, leak-free connection.

2) CPVC Pipe Union Fittings

Pipe Union Fitting | 7 Types of Union and Installation

The most general applications for CPVC pipes are for hot and cold water supply that are union fittings for chlorinated polyvinyl chloride (CPVC) pipes.

To make a strong and reliable connection, the slip-on design of these fittings is solvent cemented. Union fittings made up of CPVC are easy to install and provide a solid joint that can tolerate high pressure and temperature.

3) Galvanized Pipe Union Fittings

Pipe Union Fitting | 7 Types of Union and Installation

Galvanized union fittings are manufactured from galvanized steel which is used for water supply lines. To provide Excel corrosion resistance a zinc layer is coated over a fitting during the galvanization process.

A wrench and threaded connection should be needed to install these types of fittings. Galvanized pipe union fittings are used in older plumbing systems, but it is being pleased out due to concerns that zinc can leach into the water supply.

4) Hydraulic Unions Pipe Fittings

Pipe Union Fitting | 7 Types of Union and Installation

For operation at high pressure, and for hydraulic systems, hydraulic union fittings are specially made. These are made up of steel or brass, and they are well known for their strength and leak resistance.

For creating a secure joint to hold and fulfill the demand of a hydraulic system, threaded or compression connections are used.

5) Male Union Pipe Fittings

External threads on both ends are the male union pipe fitting is an example of a union fitting. To connect with other fittings or parts with matching female threads, this design makes it easy for connecting.

In situations where a momentary or detachable connection is required, male union fittings are often used.

6) Stainless Steel Unions Pipe Fittings

Pipe Union Fitting | 7 Types of Union and Installation

Because of their exceptional durability and resistance to corrosion, Union pipe fittings are well-liked. These are made up of stainless steel.

In fields such as food processing and pharmaceutical, Marine Applications, etc. these types of fittings are used. This type of fitting comes in a range of sizes and configuration that suits a variety of needs and this fitting also provides a reliable and leak-free connection.

7) ABS Union Pipe Fittings

Pipe Union Fitting | 7 Types of Union and Installation

The pipe that is often used in drain, waste, and vent systems, is compatible with ABS (Acrylonitrile Butadiene Styrene) union pipe fittings.

A slip-on design, a strong, long-lasting connection is created using ABS solvent cement. ABS Union Fittings provide a simple solution for connecting and disconnecting pipes in drainage systems.

Proper assembling by using taper Union

Some FAQ

Q) What is a Pipe Union Fitting?

The PUF is a type of fitting that makes it easy to connect and disconnect pipes from each other or two different pipes. It has got two parts that can be screwed or unscrewed together and gives a quick and secure way to join pipes.

They are available in a range of materials, sizes, and designs to meet a variety of applications.

Q) How Does a Pipe Union Fitting Work?

The pipe union fitting is two separate parts that can be connected or disconnected as needed as needed to both the outer and inner ends of each half are threaded. The two halves are screwed together to form a tight seal after a union fitting is inserted between the two pipes.

If disconnection is required, the union fitting can be unscrewed to separate the pipe. It is a beneficial point for union fittings in situations requiring maintenance or repair.

Q) How to Install pipe union fitting

A pipe union fitting can be easily installed by doing the following:

  • Pipes should be cut at a desired length, with a sharp and clean cut.
  • The meal threads of the pipe union fitting should be sealed with thread sealant or Teflon tape.
  • Tighten the union fitting until it is fastened to the pipe.
  • To make sure the connection is secure and leak-free, tighten the union fitting even more with the wrench. Overtightening should be avoided to damage the threads.
  • The joints can be checked for leakage by letting water flow through the system.


Pipe union fittings are those adaptable parts that facilitate simple pipe connection and disconnection.

Depending upon your specific needs, there is a union fitting for working with black pipe, CPVC pipe, galvanized pipe, hydraulic systems, stainless steel pipe, or ABS pipe.

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"Structural Engineer" with over 5 years of experience in estimation, structural design, and surveying. I am passionate about using my skills to create safe and sustainable structures. I am also a keen writer, and I enjoy sharing my knowledge and experiences with others.