Types of Pipe Fittings Used in Piping

What are Pipe Fittings?

Pipe Fittings are a Piping component that helps in changing the direction of the flow such as Elbows and Tees. Changes the size of the Pipe such as Reducers and Reducing Tees. Connect different components such as Couplings and stop the flows such as Caps. 

The materials for pipe fittings are often selected alongside the materials for the piping. Selection depends on factors such as Cost, Flexibility, Media, Environmental Conditions and required Pressure Ratings.

Common Metals include:

 Stainless Steel – Relatively strong with excellent Chemical and Corrosion Resistance. Stainless Steel is an Alloy of Steel that contains over 10.5% Chromium providing excellent Corrosion Resistancefor sanitary applications and those dealing with aggressive Fluids and Materials.

Steel – Durable and Strong with a high resistance to Heat. Steel is an Alloy of Iron and Carbon it is commonly alloyed with other Metals to improve its Corrosion Resistance and Durability. It is used in both Commercial and Industrial applications for carrying Water, Flammable Gases and other Fluids. Galvanized Steel is coated with Zinc for Rust and Chemical Corrosion Resistance. Carbon Steel is alloyed with higher levels of Carbon for increased Durability and Strength.

Aluminium – Light Weight and Corrosion Resistant. Aluminium is commonly used for plumbing and is the preferred fitting material for Aluminium Piping. By itself Aluminium has low tensile strength and is used when high Corrosion Resistance is needed. It is alloyed with Zinc, Copper, Silicon, Manganese, and/or other Metals to improve its Strength and Hardness.

Brass – Strong, Durable and Corrosion Resistant with high temperature Ductility and Good Conductivity. Brass is an Alloy of Copper and Zinc and is commonly used for Smaller Compression and Threaded Pipe Fittings in Industry because of its Machinability and its excellent performance properties. Brass Fittings can have various Protective or Decorative Finishes which should match the Finish of the Piping.

Copper – Extremely Corrosion Resistant with excellent conductivity. Copper Fittings are important or many Plumbing and Heating Applications and are commonly used for Residential water supply lines. Copper Fittings are usually used in conjunction with Copper Piping and come in either Soft or Rigid Forms. Soft or Ductile Copper is easily Bent and Manoeuvred and is the only type suitable for Flare Connections. Rigid Copper is not bendable and requires directional Fittings to go around Corners and Obstacles.

Given their diverse uses Pipe Fittings are used in several Sectors Including:

Chemical/Petrochemical: Pipe Fittings in this sector are crucial for transporting various Chemicals and Fluids Safely and Efficiently within Processing Plants and Refineries.

Municipal: Pipe Fittings facilitate the Distribution of Water, Sewage and other Utilities in Municipal Infrastructure Projects ensuring Reliable and Sustainable Public Services.

Food, Beverage and Dairy: In this Industry Hygienic Pipe Fittings are essential for maintaining sanitary conditions during the Processing and Distribution of Food and Beverage products.

Oil and Gas: Pipe Fittings play a vital role in Oil and Gas operations by Connecting Pipelines, Controlling Flow and ensuring the integrity of the Infrastructure in Exploration, Production and Distribution processes.

Power: Pipe Fittings are used in Power Generation facilities to transport Water, Steam and other Fluids essential for Operating Turbines and other Machinery.

Semiconductor: In Semiconductor Manufacturing specialized Pipe Fittings maintain the purity of process Gases and Chemicals critical for producing Electronic Components.

Marine & Dredging: Pipe Fittings are utilized in Marine and Dredging applications for constructing Pipelines, Drainage systems and Underwater Infrastructure.

Irrigation: Pipe Fittings support Irrigation Systems by connecting Pipes controlling Water Flow and distributing Water to Agricultural Fields Gardens and Landscaping Projects.

Ventilation: Pipe Fittings aid in Ventilation Systems by connecting Ducts, controlling Airflow and removing Stale Air or Fumes from enclosed spaces for better Indoor Air Quality.

The Pipes are Installed Repaired and Maintained by Pipefitters. They study the design specifications required to construct suitable Industrial Piping Assemblies, Steam Production, Heating and Cooling Systems. Additionally they might work in a variety of contexts such as Homes, Businesses and Industrial Settings where Pipe Systems need to be installed.

Pipefitter: The general term for Skilled Workers who Install, Repair and maintain Piping Systems across various Construction Projects.

Welder/Pipe Welder: Specializes in joining Pipes using Welding Techniques crucial for High-Pressure Applications.

Process Pipefitter: Works in Industries like Oil & Gas, Chemical Processing and Power Generation Installing and Maintaining Piping Systems for Transporting various Fluids and Materials.

Marine Pipefitter: Specializes in Installing and Maintaining Piping Systems on Ships and Offshore Rigs requiring expertise in Corrosion-Resistant materials and working in challenging Marine Environments.

Fire Protection Pipefitter: Installs and Maintains Sprinkler Systems and Fire Hydrant networks in Buildings.

Steamfitter: Installs and Maintains Piping systems for steam distribution in Buildings and Industrial settings

Plumber: The most common term for a Pipe Fitting professional specializing in Residential and Commercial Water and Drainage Systems.

There are different types of Pipe Fitting used in Piping Work are listed below:

Elbow

Tee

Reducer

Union

Coupling

Adapters

Olet (Weldolet, Sockolet, Elbowlet, Thredolet, Nipolet, Letrolet, Swepolet)

Valve

Cross

Cap

Swage Nipple

Plug

Bush

Expansion Joint

Long Radius Bend

Flanges

Pipe Elbow

The Elbow is used more than any other Pipe Fittings. It provides flexibility to change the Pipe Direction. Elbow is mainly available in two standard types 90° and 45°. However it can be cut to any other degree. Elbows are available in two Radius Types Short Radius (1D) and Long Radius (1.5D).

90 Degree Elbow

90 Degree Elbow is installed between the Pipes to change the direction of the Pipe by 90 Degree. Available in Long and Short Radius Form.

45 Degree Elbow

45 Degree Elbow is installed between the Pipes to change the direction of the Pipe by 45 Degree.

Long Radius Elbow

In a Long Radius Elbow the Centreline Radius is 1.5 times the Nominal Size of the Pipe or you can say 1.5 times the Diameter of the Pipe. Normally Long Radius Elbows are used in Piping as pressure loss is less as compared to Short Radius Elbows. It required more space than a Short Radius Elbow.

Short Radius Elbow

In a Short Radius Elbow the Centreline Radius is the same as the Nominal Size of the Pipe or you can say one times the Diameter of the Pipe. Short Radius Elbows are used under limited space applications. However it has a High-Pressure drop due to a sudden change in the direction of Flow.

Reducing Elbow

The 90 Reducing Elbows is designed to change Direction and Reduce the Pipe Size within a Piping System. The Reducing Elbow eliminates one Pipe Fitting and Reduces the Welding by more than one-third. Also the gradual reduction in diameter throughout the arc of the Reducing Elbow provides lower resistance to Flow and Reduces the effect of Stream Turbulence and Potential Internal Erosion. These features prevent sizeable pressure drops in the line.

Pipe Bend

Long Radius Pipeline Bends are used in Fluid Transportation Lines which require Pigging. Due to their Long Radius and smooth change of Direction the Pipe Bend has very less pressure drop and a smooth flow of Fluid & Pig is possible. 3D and 5D Pipe Bends are commonly available.

Returns – 180 Degree Elbow

Returning Elbows are used to make a 180º change in direction. Available in Short & Long Patterns. Returns are used in the Heating Coil, Heat Exchanger, Tank Vent, etc.

Pipe Tee

A Pipe Tee is used for Distributing or Collecting the Fluid from the Run Pipe. It is a short piece of Pipe with a 90-degree branch at the centre. Two types of Tee are used in Piping Equal / Straight Tee and Reducing / Unequal Tee.

Straight Tee

In Straight Tee the diameter of the branch is the same as the diameter of the Run (Header) Pipe.

Reducing Tee

In Reducing Tee the diameter of the branch size is smaller than the diameter of the Run (Header) Pipe

Barred Tee

A Barred Tee also known as a Scrapper Tee is used in Pigged Pipelines. The Tee Branch has a Restriction Bar Welded internally to prevent the Pig or Scrapper from entering the branch. The bars are Welded in the branch in a way that it will allow restriction-free passage of the Pig from the Run Pipe.

Cross

Cross is also known as four-way Pipe Fitting. A Cross has One Inlet and Three Outlets. Generally Crosses are not used in process Piping to transport Fluid. But Forged Crosses are common in the Firewater Sprinkler Line.

Pipe Reducers

A Pipe Reducer changes the Size of the Pipe. There are two types of Reducers used in Piping Concentric & Eccentric.

Concentric Pipe Reducer or Conical Reducer

In a Concentric Reducer also known as a Conical Reducer the centre of both ends is on the same axis. It maintains the centreline elevation of the Pipeline. When the centre lines of the Larger and Smaller Pipe are to be maintained the same Concentric Reducers are used.

Eccentric Reducer

In the Eccentric Reducer the centre of both ends is on a different axis. It maintains the BOP (Bottom Of Pipe) Elevation of the Pipeline. When one of the outside surfaces of the Pipeline is to be maintained the same Eccentric Reducers are required.

Swage Reducer

The Swage is like Reducers but small in Size and used to connect Pipes to Smaller Screwed or Socket Welded Pipes. Like Reducers they are also available in Concentric & Eccentric Types. Swages are available in different end types. Such as both plain ends or one plain and one threaded end.

Pipe Caps

The Cap covers the end of a Pipe. Pipe Caps are used at the dead end of the Piping System. It is also used in Piping Headers for future connections.

Stub Ends

Stub Ends are used with a Lap Joint Flange. In this type of Flange the Stub is Butt Welded to the Pipe whereas the Flange is freely moved over the Stub End. It is basically a Flange part but covered under ASME B16.9 which is why it is considered Pipe Fittings.

Piping Union

Unions are used as an alternative to Flanges Connection in low-pressure small bore Piping where the dismantling of the Pipe is required more often. Unions can be Threaded Ends or Socket Weld Ends. There are Three Pieces in a Union a Nut, a Female End and a Male End. When the Female and Male Ends are joined the Nuts provide the necessary pressure to seal the joint.

Pipe Coupling

There are Three Types of Coupling available:

Full Coupling

Full Coupling is used for Connecting Small Bore Pipes. It is used to connect Pipe to Pipe or Pipe to Swage or Nipple. It can be Threaded or Socket Ends types.

Half Coupling

Half Coupling is used for small bore branching from a Vessel or Large Pipe. It can be Threaded or Socket type. It has a Socket or Thread End on only One Side.

Reducing Coupling

Reducing coupling is used to connect two different sizes of pipe. It is like a concentric reducer that maintains a centreline of the pipe but is small in size.

Pipe Nipple

The Nipple is a Short Pipe Stub with a Male Pipe Thread at each End or at one End. It is used for connecting two other Fittings. Nipples are used for connecting Pipes, Hoses and Valves. Pipe Nipples are used in Low-Pressure Piping.

Socket Weld and Threaded Pipe Fittings

Socket Weld and Threaded Pipe Fittings are Forged products and classified based on their pressure-temperature rating. They are available from NPS 1/8” to 4”. These Fittings are available in four pressure-temperature rating classes.

3000 & 6000 Class Fittings are available in both Threaded and Socket Weld types.

9000 Class Fittings are available in only the Socket Weld Type.