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 resistance for
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.
Galvanised 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 their machinability and their 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 flares.
Connections. Rigid copper is not bendable and requires directional Fittings to go around corners and
Obstacles.
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.
