20 Types of Plumbing Fittings Explained: With Photos

Modern plumbing systems are designed to be as easy to assemble as possible. However, unless you are a trained plumber, you might not know which plumbing fittings are the best fit for the job.

There are countless plumbing fittings types, sizes, and materials to consider before you go to work. It’s easy to get intimidated but fittings aren’t as complicated as they might initially appear.

In this article, we will explain 20 types of plumbing fittings that you might encounter when undertaking DIY tasks. We will also describe the different materials you can find the fittings in and which jobs they should be used for.

Types of Plumbing Fittings

1. Adapter

An adapter has “male” and “female” ends. The male end has threads on the outside and the female has them on the inside so they can fit together.

They are used to connect pipes of different sizes and can even turn a male pipe into a female, or vice versa.

There are three types of adapters: male, female, and straight-threaded. If an end of the adapter has no threading, it needs to be welded or soldered onto the pipe.

Adapters are essential when extending or terminating pipe runs. Leak-free adapters can withstand high pressure and are commonly used in gas or water pipes. They also provide a smooth transition from piping to tubing systems.

You can find adapters in a variety of materials, including:

• Steel
• Aluminum
• Rubber
• Brass
• Copper
• Cast iron
• Polymers

2. Nipple

A pipe nipple is one of the most popular types of fittings. It is also very important and connects pipes to appliances such as water heaters. It can connect two straight pipe runs.

The nipple fitting has two male ends and is available in various materials and finishes, including:

• Brass
• Aluminum
• Copper
• PVC
• Carbon steel
• Stainless steel

There are five main types of pipe nipples. They are:

• Weld nipple: Used to connect tube fittings. They are strong and can withstand extreme pressure surges, vibrations, and changes.
• Hexagon nipple: This has two threaded ends and a hexagonal center. Available in a variety of materials, lengths, and threads.
• Swage nipple: Used to transfer fluids from one pipe size to a different size.
• Barrel nipple: A short tubular nipple with an external taper thread at both ends, and is un-threaded between them.
• Close nipple: Threaded from end to end. Also referred to as a “running nipple”.

Before buying a pipe nipple, it is important to consider the material, thickness, and diameter to ensure you choose the correct fitting.

3. Union

Union fittings have three parts: a nut, a female end, and a male end. They are designed to connect two pipes in such a way that they can be detached without causing damage to them. They are used in maintenance and in situations where future replacements are likely.

Pipe unions are available in a wide range of durable materials such as:

• Cast iron
• Nickel
• Brass
• Bronze
• Plastic
• Rubber

One of the main advantages of union fittings is that they are easy to install.

They are used for various industrial and municipal settings such as process piping and wastewater systems. When buying a union fitting, consider which type and size you need.

4. Barb

Barb fittings usually have a male thread at one end and a tapered, ridged cone at the other. They are designed to grip the inside of a tube and seal the connection.

When the barb fitting is inserted, the hose or tube will expand and then relax. As the tube or hose returns to its original size, the connection is sealed and becomes difficult to undo. Barbed fittings are often used for gas, air, and fluid control applications in low pressure.

Plastic barbs are used for cold water connections. Brass barbs are used for hot water. Before buying a barb fitting, consider the following:

• Material compatibility
• Single or multi-barb
• Hardness of the tube or hose
• Inner diameter of the hose or tube

5. Coupling

Couplings are very similar to unions. However, they can’t be detached without damaging the pipes.

Couplings can be used to connect two pipes of the same size and diameter. They are also commonly used to move from one pipe size to another; a bell reducer is often used to do this as it connects a larger pipe to a smaller one.

You will find couplings with female threads or unthreaded. Unthreaded couplings are used with either copper soldering or plastic solvent welding.

There are two other common types of couplings:

• Compression: Connects two pipes using gaskets or rubber seals at both ends. The seals prevent leaking.
• Slip: Usually used to repair a specific length of damaged pipe.

Coupling fittings are available in a range of materials; including:

• ABS
• Chrome-plated brass
• Brass
• CPVC (chlorinated polyvinyl chloride)
• PVC
• Stainless steel

6. Cross

Crosses are four-way fittings, a combination of two tees (see below). They consist of one inlet and three outlets, and often have a solvent-welded socket or female-threaded ends.

Cross fittings are less popular than tees because they can stress pipes during temperature changes due to the four open ends.

Crosses are mostly used in plumbing systems where thermal expansion isn’t an issue, such as fire sprinkler systems.

Cross fittings are available in the following materials:

• Brass
• Steel
• Stainless steel
• Malleable
• PVC

7. Tees

Tees are three-way fittings. They look like couplings with an extra outlet in the middle. They are essentially short pipes with a 90-degree “branch” at the center.

There are two main types of tees:

• Straight tee: Used in setups where the main pipe is the same width as the tee branch.
• Reducing tee: Used when the tee branch is smaller than the main pipe.

Tees are available in a range of materials:

• ABS
• Chrome-plated brass
• Brass
• Copper
• CPVC
• PVC
• Stainless steel

8. Saddle Tee

Saddle tees are shaped similarly to a real saddle. They are only available in PVC and are used to add a tee to an existing pipe without needing to cut or re-solder it.

These are often used in irrigation systems when you need to add a new sprinkler line. Saddle tees are “snapped” onto the pipe using glue. Once the glue has set, a new hole is drilled.

9. Wyes

Wyes look like the letter “Y”. They are generally used in drainage fittings and have a 45-degree branch.

The angling of the branch is designed to reduce turbulence and friction. Wyes connect vertical drain pipes to horizontal ones.

Wye fittings are available in:

• ABS
• PVC
• Brass

10. Flanges

A flange is a round fitting used to connect pipes. The pipes are either threaded or welded to the middle of the flange, and then sealed together. The holes on the outside are for bolts.

Flanges are mainly used for industrial applications due to their ability to withstand high pressure. You can also find flanges in residential pump systems.

In homes, PVC flanges are used when mounting toilets onto the floor. These are also referred to as “closet” flanges.

They are available in several materials, including:

• Copper
• Malleable
• PVC
• Brass

11. Elbows

Elbow fittings are curved and used to change flow direction. They are mostly made with 45-degree or 90-degree angles and can be sweated or threaded.

The ends of the elbow fitting can be designed for butt welding, threading, or socketing. A reducing elbow has two ends of different sizes to connect pipes with varying widths.

Elbows are made from these materials:

• Brass
• Chrome-plated brass
• CPVC
• Copper
• ABS
• PVC
• Stainless steel

12. Caps

Caps are used to seal the end of an open pipe and will contain liquid and gas. The cap can be attached to the pipe end with interior threading (female), or a solvent-welded socket.

The outside of a cap can be square, round, rectangular, I-shaped, or U-shaped; some will even have a handgrip.

Caps are available in a range of materials:

• ABS
• Copper
• CPVC
• Brass
• Chrome-plated brass
• PVC
• Malleable
• Stainless steel

13. Plugs

Plugs are used similarly to caps, but rather than being fitted over the end of a pipe, they are fitted inside. They are usually threaded to allow the plug to be removed in case the pipe is needed in the future.

They are available in many of the same materials as caps:

• ABS
• Copper
• Brass
• Stainless steel

14. Bushings

Bushings look like small screws. They are mainly used to connect pipes of different sizes, reducing a large fitting to a small pipe. They can be threaded on the inside and outside, but this isn’t always the case.

Bushing fittings are smaller than unions and couplings and are often used in similar situations.

This type of fitting is available in:

• Brass
• Chrome-plated brass
• CPVC
• Copper
• ABS
• PVC
• Malleable

15. Mechanical Sleeve

A mechanical sleeve joins two pipes using a screw or piece and is easy to install.

The sleeve is usually made of rubber and is inserted into a stainless steel clamp. The clamp compresses the rubber, which creates a tight seal.

This type of fitting is slightly flexible and can be used to fix misalignments in awkward places.

16. Valve

A valve is used to regulate or stop the flow of gas or liquid. Valves are usually categorized by their application, such as:

• Isolation: Used to disconnect a part of a piping system temporarily. Can be left open or closed, and can remain in place for years before needing replacement.
• Throttling: Used to control the pressure of a liquid. Designed to withstand stress, but they will eventually wear out. Usually installed alongside an isolation valve as an extra safety measure.
• Non-return: Also called check valves, these allow fluid to flow freely in one direction, but prevent reverse flow. Often used in sewage and drainage systems.

Valves are mainly made of metals such as:

• Bronze
• Cast iron
• Cast steel
• Stainless steel
• Carbon steel is used for high pressure or high temperatures

17. Reducer

A reducer is designed to reduce flow. It comes in two types:

• Concentric reducer: Looks similar to a cone. Designed to join two pipe sections on the same axis. Usually used when there is a change in pipe diameter.
• Eccentric reducer: Used in piping systems where the upstream pipe is larger than the downstream pipe.

Reducers are available in a range of materials such as:

• Carbon steel
• Alloy
• Stainless steel

18. Clean-Outs

A clean-out fitting has removable parts that enable access to drains without needing to remove the entire fitting. Clean-outs will allow an auger (a type of drill) to enter and clean a clogged drain.

It is important that clean-outs are placed in accessible locations to ensure you can reach them with an auger. Larger plumbing systems usually feature several clean-outs spread throughout the system.

Clean-outs are mostly made out of PVC.

19. Combo Tee

Combination tees have a gently curved central branch. They are used in drains to provide a smooth, slightly curving path and reduce the risk of clogging. The gentle curve also makes it easier for a plumber to push a snake tool through.

These fittings are available in PVC material.

20. Diverter Tee

A diverter tee is mainly used in pressurized hydronic heating systems. It diverts portions of the flow from the primary line into a side branch that is connected to a heat exchanger.

It is designed to allow a regular flow through the main line, even if the branch is shut off.

Installing a diverter tee can be challenging. It features directional marking that must be followed. If it’s installed backward, it won’t function properly.

Diverter tees are available in similar materials to standard tees:

• Stainless steel
• ABS
• Brass
• Chrome-plated brass
• Copper
• PVC

Plumbing Fittings Material Guide

Choosing the right material can be the difference between a watertight system and one that leaks. The most popular materials include:

• Cast-iron fittings: Can be used in DWV systems and are usually black.
• PVC schedule 40: Used in DWV systems, irrigation, and outdoor applications such as pools and sprinklers. The material can also be used in pressurized systems. It can’t be used with compressed gasses or air.
• PVC schedule 80: Can be used in pressurized systems. It is suitable for pressurized liquids, but not gasses or air.
• Copper: Used for hot and cold water distribution in pressurized systems.
• Acrylonitrile butadiene styrene (ABS): Commonly used in DWV systems in western parts of the United States.
• Brass: A mixture of metal alloys such as copper and zinc, brass is a common material for fittings. It is used in pressurized systems, mostly for hot water applications ⁽¹⁾.
• CPVC (chlorinated polyvinyl chloride): Commonly used for drinking water at higher temperatures (up to 200 degrees). It can withstand higher temperatures than standard PVC ⁽²⁾.

Types of Pipes

Newer homes across the United States (built since the mid-1970s) usually have plastic pipes and fittings. The materials used are rated by the American Society for Testing and Materials.

Older homes (pre-1960) used cast iron or galvanized steel pipes for their drain, waste, and vent systems (DWV). DWV systems are designed to remove wastewater while preventing sewer gasses from entering homes.

Today, homes are fitted with PVC (polyvinyl chloride) and copper pipes. These materials are sturdy, durable, and easy to install ⁽³⁾. They also feature a range of plumbing connection types for ease of installation.

FAQs

Where Can You Buy Plumbing Fittings?

Plumbing fittings can be found at your local hardware and supply stores. You can also find a huge range of fittings available online at sites such as Amazon, Home Depot, Lowe’s, and eBay.

How Do You Find the Correct Pipe Fitting?

The first question to ask yourself is what you need the fitting for specifically. Fittings serve as pipe connectors and connect the appliances in our homes to the wider plumbing system. Some are designed to redirect, others to extend.

Size is another important factor. Fittings are usually measured by the inside diameter (ID) and outside diameter (OD) of the corresponding connection. In most cases, this is measured in inches or millimeters.

The inside diameter refers to the hollow part of the fitting. The outside diameter includes the thickness of the casing ⁽⁴⁾.

How Do I Identify a Pipe Fitting?

To maintain consistency and dependability in your piping system, it is necessary to identify which pipe fitting is optimal for the application you are working on.

Compression fittings are an excellent choice for connections made from metal to metal. Pipes can be joined together with these fittings by applying pressure to a compression ring, gasket, or ferrule.

In most cases, the compression is achieved by firmly tightening a nut into the fitting over the ferrule and the piping.

This both secures the piping and causes it to be compressed. Assembly of standard compression fittings does not need the use of any tools. Because of this, they are convenient, as well as quick and easy to put in place.

Pipe connections require very particular surfaces, which end fittings provide.

Flange fittings are ribs, collars, rims, or edges with flat surfaces perpendicular to the connected pipe. Flange fittings can also be called flanges. Threading, welding, and clamping are some of the other ways that these surfaces are kept together.

Threaded fittings are constructed with screw threads on their inner and outer surfaces. They are designed to be used with a pipe with threads that are a perfect match.

Straight threads are threads that are used to produce a simple connection that does not have a seal.

Tapered threads, on the other hand, are a type of thread that can produce a leak-proof seal for pressurized liquids and gases. By applying a seal tape or coating, it is possible to increase the reliability of the seal.

The diameter of the pipe is used to measure and determine the size of the threads. National Pipe Thread, sometimes known as NPT, and British Standard Pipe are two examples of common thread size standards (BSP).

Despite this, there are a variety of other standards that are utilized differently depending on the sector and the country.

What Is a Valve Fitting?

A valve is a specific fitting that enables the control, regulation, and direction of fluids moving through a pipe.

You can find valve fittings in plumbing systems. The flow of water, the ability to access water, the prevention of backflow, and the adjustment of water pressure are all common uses for valves within a system.

What Is a Flange Pipe Fitting?

A pipe “flange” is a metal ring welded onto a pipe’s end. It has holes drilled in it that run parallel to the center line of the pipe so it can accept numerous bolts.

Before tightening the bolts, pressure-tight flange joints are created by inserting a gasket in the shape of a donut between the flange pairs and then retightening the bolts.

The material used to make gaskets is typically softer than the material used to make flanges. The gasket will be “crushed” between the two flanges when sandwiched between them, ensuring that any potential leak pathways are sealed.

What Is a Tee in Plumbing?

A pipe tee fitting is a type shaped like the letter T. It includes one primary connecting line and two outlets angled at 90 degrees each.

It is a pipe with outlets near one another and is used to join pipes at an angle of 90 degrees. Pipe tee fittings are utilized in various contexts, including commercial and industrial settings.

What Is NPT Thread Size?

Pipe threads that conform to ANSI/ASME B1.20.1 are NPT, which stands for National Pipe Tapered threads. Tapered threads on pipes and fittings are measured using this standard developed in the United States.

Pipes transporting hydraulic fluids can benefit from an effective seal when threading them. The NPT threads and the NPS threads, also known as the National Pipe Straight threads, are not interchangeable, although the NPT threads are sometimes referred to as MPT (male pipe threads).

Instead of a bolt’s straight threads, a taper thread will pull tighter and create a better seal than the straight threads. To create a completely watertight seal, you must use either a sealant compound or PTFE (polytetrafluoroethylene) tape.

What Does FIP Mean in Plumbing?

FIP is short for Female Iron Pipe. Any threaded female plumbing connection can be fitted with a MIP fitting, which you can screw into another type of fitting or piece of equipment.

MIP fittings are quite popular in residential residences. You can usually find them on the ends of valves designed for use with copper tubing. MIP fittings are available in both metric and imperial sizes.