Top 15 Pipe Fitting Types and Their App

Top 15 Pipe Fitting Types and Their Applications

To make good piping systems, you need to understand the variety of pipe fittings. Let’s survey the top 15 fittings that are commonly used in different industries.

1. Elbow Fittings

Elbow Fittings

Elbow fittings are L-shaped connectors that, usually at 45° or 90° angles, change the direction of pipe flow. They come in different radii with long-radius elbows providing less flow resistance than short-radius ones.

Materials

You will find elbow fittings made from materials like stainless carbon steel, PVC, steel, copper, and brass. The material choice depends on aspects such as corrosion resistance, temperature requirements and pressure ratings.

Applications

In the oil and gas industry, refineries use elbow pipe fittings to move fluid in complex piping networks. Chemical processing plants use them in reactor feed systems. HVAC systems use elbows for plumbing and ductwork. Power plants and water treatment facilities use these fittings in their steam distribution systems.

2. Tee Pipe Fittings

Tee Pipe Fittings

They have a T-shaped design with one inlet and two outlets that allow for the combining or branching of fluid flows. Tee pipe fittings have equal or reducing outlets known as reducing tees or straight tees.

Materials

Common materials for tee fittings include stainless steel, copper, PVC, CPVC, carbon steel and cast iron. The application requirements such as chemical compatibility and pressure ratings determine material selection.

Applications

You will encounter tee fittings in different industries. The petrochemical industry uses them in distillation columns for fluid distribution while water treatment plants put tees in filtration systems. Fire sprinkler systems depend on these types of pipe fittings for branch line connections.

In the food and beverage industry, tees are important in process piping for ingredient mixing. HVAC systems also benefit from tees in refrigerant distribution for multi-zone air conditioning units.

3. Pipe Couplings

Pipe Couplings

Among the different pipe fitting types, the pipe coupler is important for joining two pipes of the same diameter. These fittings come in styles like compression, slip and grooved couplings. Each pipe coupling is suited for particular situations.

Materials

Pipe couplings are usually made from materials like carbon steel, PVC, stainless steel, copper, and malleable iron. The choice depends on factors like temperature resistance, pressure rating and chemical compatibility.

Applications

The oil and gas industry depends on pipe couplings to connect long pipeline stretches. In chemical processing plants, these fittings join pipes in corrosive environments. Municipal water systems use couplings for quick repairs and extensions. You will find these versatile fittings in practically every industry that depends on piping systems.

4. Pipe Union

Pipe Union

Pipe unions stand out among fitting types due to their unique design for easy disassembly and reassembly. A union nut and two end pieces are the three main parts of a union pipe fitting. This setup permits for appropriate modifications and maintenance without cutting pipes.

Materials:

You will find pipe unions made from different materials like brass, PVC, stainless steel, and malleable iron. The choice depends on factors like pressure requirements, corrosion resistance and thermal expansion properties.

Applications:

Refineries use pipe unions to remove equipment for replacement or cleaning. In HVAC systems, they connect cooling and heating units. The pharmaceutical industry uses unions in sanitary piping systems. These fittings facilitate easy fixture replacement and system upgrades even in your home.

5. Pipe Adapter Fittings

Pipe Adapter Fittings

Adapter fittings connect the gap between pipes of different materials, sizes or thread types. They come in many arrangements such as female-to-female, male-to-female and reducing adapters. This flexibility assures compatibility between diverse piping parts.

Materials:

Common materials for adapters include brass, PVC, stainless steel and cast iron. The specific choice depends on the pressure rating, corrosion resistance and temperature requirements of the situation.

Applications:

You will spot pipe adapters fitting in petrochemical plants that connect pipes of different sizes in complex processing units. Water treatment facilities use them to join pipes of different materials. HVAC technicians depend on adapters to connect copper refrigerant lines to steel compressor fittings. Many industrial machines require adapters to interface with standardized piping systems.

6. Reducer Pipe Fitting

Reducer Pipe Fitting

Reducer fittings are important in decreasing pipe diameter which allows for transitions between different pipe sizes. They come in two main types, first one is concentric reducers which maintain a centered flow, and the second one is eccentric reducers which keep one side of the pipe aligned.

Materials:

Manufacturers usually produce reducer pipe fittings from carbon steel, PVC, stainless steel and copper. The material selection depends on the pressure requirements of the system, temperature range and chemical compatibility.

Applications:

Oil refineries use pipe reducer fittings to manage flow rates between processing units of varying capacities. In chemical plants, they control pressure in reactor feed lines. Municipal water systems use reducers to transition from main lines to smaller distribution pipes. HVAC engineers optimize airflow in ductwork systems with these fittings.

7. Pipe Caps

Pipe Caps

Pipe caps serve as important fittings to seal the end of a pipe or fitting. They provide a tight, pressure-resistant closure and come in different styles including threaded, weld-on and slip-on caps.

Materials:

You will find pipe caps made from carbon steel, PVC, stainless steel and brass. The material choice depends on pressure rating, corrosion resistance and temperature requirements of the situation.

Applications:

In oil and gas pipelines, caps seal off unused branches or provide temporary closures during maintenance. Chemical processing plants use them to isolate sections of piping systems. Water treatment facilities depend on pipe caps to protect pipe ends from impurities. During servicing or installation, HVAC technicians use caps to seal refrigerant lines.

8. Pipe Plugs

Pipe Plugs

Pipe plugs are small fittings that are built to seal openings in valves, pipes or other fittings. They come in different types which include expansion, threaded, and mechanical plugs. Each type is suited for particular situations.

Materials:

Manufacturers usually make plugs from materials like brass, stainless steel, and rubber. The choice depends on chemical compatibility, pressure rating and if the seal is temporary or permanent.

Applications

In refineries, pipe plugs are used for pressure testing newly installed piping systems. In automotive industries, they are used to seal transmission housings and engine blocks. Plumbers use pipe plugs for temporary closures and leak testing in the plumbing system. Likewise, hydraulic systems depend on pipe plugs to seal unused ports in valves and manifolds.

9. Pipe Bushings

Pipe Bushings

Pipe bushings perform an important role in connecting pipes of different diameters. These pipe fittings have male threads outside and female threads inside which permits smooth transitions between pipe sizes.

Materials

You’ll find pipe bushings made from many different materials like carbon steel, PVC, brass and stainless steel. The choice depends on factors such as pressure rating, corrosion resistance and chemical compatibility with the fluid that is being transported.

Applications

In oil refineries, pipe bushings connect instruments to process lines of varying sizes. You’ll find them in chemical plants and use them to adapt small sampling lines to bigger process pipes. HVAC technology depends on bushings to join different refrigerant line sizes. In hydraulic systems, these fittings adapt parts to ports on pumps and valves.

10. Pipe Nipples

Pipe Nipples

Pipe nipples are short pipe pieces of pipe with threads on both ends. They come in different lengths and thread configurations like long, short and close nipples.

Materials

The main materials that are used to manufacture pipe nipples are carbon steel, stainless steel, PVC and brass. The choice depends on the needs for temperature range, pressure and corrosion resistance.

Applications

You’ll see pipe nipples in different industries. Petrochemical industries use them to connect instruments and valves to process lines.  In plumbing systems, nipples connect fixtures to supply lines and create offsets for proper alignment. You can also find them in water treatment facilities for the joining of pumps to piping systems. HVAC engineers use them to extend pipe runs in tight spaces.

11. Pipe Flange

Pipe Flange

Pipe flange is one of the important types of pipe fitting. It makes strong, leak-proof links between valves, pipes and other equipment. They come in different types which include slip-on, weld neck and blind flanges. Each type fits for different uses.

Materials:

It is mainly manufactured from materials like carbon steel, alloy steel, stainless steel and cast iron. The choice depends on the required uses of temperature resistance, pressure rating and corrosion protection.

Applications

Oil refineries use pipe flanges to connect large pipes that carry refined products and crude oil. In chemical processing plants, this type of pipe fittings joins reactor vessels to piping systems. Power plants depend on flanges to connect high-pressure steam lines. Water treatment facilities use them to join valves, pumps and filtration machinery to main pipelines.

12. Valves

Valves

Valves regulate the pressure, flow and direction of fluids in piping systems. They come in different types such as globe, butterfly, gate and ball valves. Each type gives distinctive flow control features.

Materials:

You’ll find valves made from materials like carbon steel, brass, stainless steel and PVC. The selection depends on pressure rating, corrosion resistance and compatibility with the controlled fluid.

Applications

The oil and gas industry uses valves to regulate flow in pipelines and processing units. Chemical plants use them to manage product distribution and regulate reactant flow. HVAC systems depend on valves to control refrigerant and water flow. Municipal water systems use these pipe fittings to isolate sections for the management and maintenance of water distribution.

13. Cross Fittings

Cross Fittings

Cross fittings have four openings arranged in a cross shape that lets you connect four pipes at right angles. This flexible type of pipe fitting permits combination or distribution of fluid flows in multiple directions.

Materials:

Main materials for cross pipe fittings manufacturing include carbon steel, stainless steel, copper and PVC. The selection of this type of pipe fitting is based on corrosion resistance, pressure rating and compatibility with the fluid that is being transported.

Applications

Fire protection systems use cross fittings to distribute water to multiple sprinkler lines. In chemical processing plants, they distribute or combine reactants and products. Oil refineries also use them in manifold systems for proficient fluid distribution. HVAC systems create multiple branch lines from one main supply.

14. Y-Fittings

Y-Fittings

Y-fittings focus on pipe components that split or merge fluid flows at a 45-degree angle. These fittings offer smoother flow characteristics than T-fittings which helps reduce pressure drop and turbulence in piping systems.

Materials:

You will find Y pipe fittings made from different materials including ductile iron, PVC, stainless steel and HDPE. The choice of material depends on pressure requirements, chemical compatibility and particular application needs.

Applications:

In wastewater treatment plants, Y-fittings combine multiple inlet streams into a single process line. Brewing industries use them to split product flows for different packaging lines. HVAC systems use Y-fittings to merge return air ducts. Hydraulic systems use these fittings to create bypass loops or combine multiple pump outputs.

15. Pipe Olet

Pipe Olet

Pipe olets are particular fittings designed for branch connections on larger diameter pipes. They come in different styles such as threadolets, weldolets and sockolets. Each style is suited for particular joining methods and uses.

Materials:

Common materials for pipe olets include stainless steel, carbon steel and alloy steel. The selection depends on factors like temperature resistance, pressure rating and corrosion resistance required for the specific situation.

Applications:

Oil refineries use pipe olets to create branch connections for instrumentation and sampling points on large process lines. In power plants, these fittings connect small-bore pipes to main steam lines. Chemical processing facilities add injection points for additives or catalysts using olets. Natural gas pipelines contain olets to install pressure relief valves and monitoring equipment on high-pressure mains.

The 18 Types Of Pipe Fittings Explained

By  Kathy Adams Dec 29, 2021 9:39 am EST

Reviewed by Gary Sprague

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Whether you're attempting a plumbing project yourself or hiring a professional plumber to do the job, it's good to know the terminology for the various pipe fittings that might be needed. Some pipe fittings look similar or have similar applications, but using the wrong one might cause plumbing problems, or it may not meet local plumbing codes. These 18 fittings are the types most commonly used for water supply, drainage, and venting for the plumbing system in any home.

1. Tees and Sanitary Tees

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1. Tees and Sanitary Tees

A tee fitting is one of the easiest to recognize. It looks a lot like a capital T, allowing for flow in a straight line and at a 90-degree angle from the main flow. These come in handy wherever a water outlet is needed, such as adding water lines to each floor in a house off the main supply line. They're also used to combine two pipes into one outlet in some cases. A septic tank also has tees; if these are not preinstalled, you'll have to add them to help prevent tank failure.

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A sanitary tee is used for drain connections with the top part of the capital "T" positioned sideways so the top of the letter T is vertical, allowing air to flow through for venting purposes. The part of the pipe that's horizontal is for wastewater coming from a horizontal pipe, traveling into the vertical drainpipe for effective drainage. These are often required by code and installed in this manner. The drainage plumbing beneath a bathtub is one common location for a sanitary tee.

2. Wyes

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2. Wyes

A wye fitting resembles the lowercase letter "y," with the longer side as a straight run and the shorter side branching off from it at a 45-degree angle. Wyes are often used for drainage, such as two inlets going into one outlet. In a sanitary wye application, the letter "Y" lies on its side with the shorter angled part angling upward to connect to a vertical drainpipe; it may be connected to an elbow to make the vertical connection. The wastewater enters the wye from above and also from the side, joining to a horizontal drainpipe. Using a wye here instead of a sanitary tee is important because a tee shape could allow wastewater to flow back upstream, which could create plumbing issues.

3. Cross Fittings

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3. Cross Fittings

A cross fitting is a lot like a tee, but the piece instead looks like a cross or plus sign. It has four equally sized openings designed to connect four pipes, each at 90-degree intervals from the next along the same plane. They're set up for one water inlet and three outlets or three inlets and one outlet. They're not as common indoors as many other pipe fittings, but they're often used for sprinkler and irrigation systems.

4. Elbows

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4. Elbows

Elbows are one of the most common connectors used in plumbing, as they allow for "bends" that would be difficult to accomplish if not impossible in a single piece of pipe. They're usually angled at 90 or 45 degrees and sometimes at 22.5 or 60 degrees. Elbows connect runs of pipe wherever such angles are needed. They usually fit the same pipe size on each end; if one end is smaller, it's called a reducing elbow. Elbows might be socketed to fit over the end of a pipe, or they may have either male or female threads at either end.

Street elbows have female threads at one end and male threads at the other in many cases, but they may have a hub at one end and no hub on the other. If they're not threaded, they require solder or glue depending on their composition.

5. Couplings

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5. Couplings

A coupling usually joins two pieces of the same pipe material that are also the same size. It's a solid piece that either has female threads on the inside of both ends or no threads. The nonthreaded version requires gluing if it's any form of PVC or soldering if it's copper. Couplings come in handy when a piece of pipe is too short, allowing you to add another pipe to extend it. They're also useful for repairing a leaky pipe. Reducing couplings or bell reducers have a different size at each end, allowing you to switch sizes along the pipe run. They're designed to be somewhat permanent once installed and may need to be cut out if there's a problem with one of the connected pipes later.

6. Unions

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6. Unions

A union comes in handy in places where a coupling won't work to connect two threaded pipes, as the union has a nut as its own tightening mechanism. This means you won't need to twist the pipes into it; instead, you twist the union fitting onto one pipe end and then slide the nut over the other pipe and tighten the nut to complete the connection. Unions are available in the usual metal and PVC pipe materials and often have male and female ends. They're also easy to remove in the event of repairs somewhere along the line.

7. Caps

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7. Caps

Sometimes, it's necessary to close off an end of a pipe, and a cap is a good way to do so. A cap fits over the top of a pipe to seal it. Some are threaded, but many are not and are instead kept in place with glue or solder, making the seal somewhat permanent. Caps may be made of a thermoplastic called ABS as well as PVC, CPVC, copper, stainless steel, or a chrome-plated brass.

8. Plug Fittings

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8. Plug Fittings

Like a cap, a plug fitting seals off the end of an otherwise open pipe. The difference between a cap and plug is that a cap goes over the end of a pipe, while a plug partially fits into the pipe end with another part sticking out, somewhat like a stopper for a wine or champagne bottle. Plugs are often threaded to twist into the open end of a pipe, which also makes them easy to remove if necessary.

9. Flanges

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9. Flanges

A flange is a piece that has a flat ring with holes for bolts on one end and a protruding part that accepts a pipe. In some cases, the fitting is threaded, but it may require welding. They're often used to mount the toilet over the waste pipe and for household pump systems. Some people use them when making industrial-style furniture as a means to secure pipes to slabs of wood, with the pipes serving as legs and the flanges as the leg-mounting hardware. They're often made of brass, copper, or PVC.

10. Nipples

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10. Nipples

Unlike some of the other pipe fittings, nipples don't resemble their name in any way. Instead, they're short pieces of plumbing pipe with threads at each end on the outside of the nipple. These are often used to connect other pipe fittings rather than two pipes in a straight line. Some nipples, called closed nipples, are threaded over their entire exterior. Nipples may be made of any common plumbing metal or PVC.

11. Reducers

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11. Reducers

A reducer is narrower at one end than the other, reducing the flow of liquid passing through it as it narrows. A concentric reducer looks like a symmetrical cone with the narrower opening centered on the narrow end, while an eccentric reducer has the narrow opening offset from the center a bit. The eccentric style helps reduce air bubbles in the pipe, especially when the pipes are horizontal. Reducers might have threads but not always.

12. Adapters

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12. Adapters

Adapters are often used to change the type of end on a pipe, such as from male to female or from nonthreaded to threaded. They often have male threads on the narrow end, which goes into a pipe, and female or inside threads in the larger area that looks like a nut. They're usually used for PVC or copper pipes, and if they aren't threaded, they could be soldered, glued, or, in some cases, welded.

13. Barbed Fitting Connections

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13. Barbed Fitting Connections

Plumbing fittings connect in various ways depending on the material and the application. Barbed fittings connect pipes to flexible plastic materials, such as PEX and polyethylene, or they may be barbed all over to accept flexible tubing at each end. The barbed fitting may be threaded on one end and then have concentric rings or barbs on the other end, which connects to a hose. Clamps and/or special crimping tools are often used with these to ensure the tubing doesn't slip off the barbs. The barbed piece is brass for a hot water connection and some form of plastic for cold water applications. Plastic barbed fittings also work on hot water lines as long as they're at least 18 inches from a heat source.

Barbed connections are available on all sorts of fittings, such as elbows, reducers, couplings, and tees. Glue usually isn't used with barbed fittings because most adhesives aren't compatible with both brass and plastic.

14. Sweat or Solder Connections

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14. Sweat or Solder Connections

Sweating, or soldering, is required for many metal pipe scenarios where the pipe isn't threaded, such as when connecting plain copper elbows to unthreaded copper pipe. Due to the high heat required, this type of soldering requires a torch rather than a soldering iron. When done properly, this connection stays leak-free for years. It's used for both brass and copper pipes and requires extra care and a heat shield for the surrounding area while working to prevent burning joists and the like.

15. Solvent and Glue Connections

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15. Solvent and Glue Connections

Solvent welding creates a permanent adhesive bond between two similar plastic plumbing pieces. Unlike a traditional adhesive, a solvent adhesive contains materials that soften the plastic as well as resin that helps it harden again, all within one product. The plastic pieces must be cut cleanly and deburred, as any debris may cause a faulty connection.

Use a solvent adhesive by first test-fitting the pipe and whichever connector you're using. Once you're sure of the fit, take the pieces apart and brush the solvent adhesive over the outside of the pipe and the inside of the connector. Push and hold the pieces together for at least 30 seconds and they'll permanently bond together. Be sure to read the adhesive label before use to ensure it works on the type of plastic you're connecting.

16. Threaded Pipe Connections

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16. Threaded Pipe Connections

Threaded pipe connections are among the easiest to work with, as there's usually no gluing or soldering required. These come in handy for any PVC pipe connections as well as metal. If the project pipe has threads, any connections you make to it should also be threaded using the same materials. Threaded pipe fittings are generally the easiest to remove and replace since it's simply a matter of loosening the fitting with wrenches to remove it.

17. Compression Pipe Connections

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17. Compression Pipe Connections

A compression fitting, often made of brass, copper, or plastic, has several pieces that work together to compress the connection for a tight seal. They're often used for water shutoff valves to toilets and sinks. Each compression fitting has a compression ring or "olive," a compression seat, and a compression nut. Tightening the nut tightens the other parts together, creating a good seal.

18. Push-Fit Connections

Lowe's

18. Push-Fit Connections

Push-fit connections are easy to use, as they simply slide over the pipe and push into place. The inner workings of a push-fit connector have stainless teeth on the inside and O-rings that help prevent leaks. The setup generally works well as long as the pipe inside the fitting has been cut properly and has no burrs or debris that might prevent a good seal. Push-fit connectors are often used for water-supply lines, but it's important to check local plumbing codes first, as they may not be allowed in areas that are difficult to access, such as deep inside a wall without an access panel.

Pipe fittings come in various shapes and sizes. The following is a list of pipe fittings that are commonly used in piping projects.

·Elbow

·Reducer

·Tee

·Coupling

·Adapters

·Union

·Valve

·Cross

·Olet

·Cap

·Plug

·Swage Nipple

·Expansion Joint

·Bush

·Long Radius Bend

·Steam Traps

·Flanges

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