What are the different types of Pipe Fittings?

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Fittings are necessary for piping systems to change direction and connect to all of the tools, equipment and devices needed for operation. The fitting take-out is the term used to describe the standard dimensions in which these fittings are made.

A fitting is essentially any pipe component that fastens permanently to a pipe. Fittings need to be made for all pipe types and connection types, including threaded, flanged, and welded. Although socket-welded and threaded fittings come in diameters up to 4, they are not frequently utilised in diameters greater than 2.

List of different types of Pipe Fittings

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Fittings can be categorised based on their purpose or the material they are made of.

MOC is typically used to categorise the different standard fitting criteria. However, we shall look at the fittings according to their purpose and function. Because there are so many different combinations of materials and purposes, the range of fittings is astounding.

List of Pipe Fittings

• Flanges ASME B16.5 and ASME B16.47
• Elbow
• Tees
• Reducers concentric and Reducers eccentric
• Reducers concentric and Reducers eccentric
• Unions
• Caps and Plugs
• Nipples and couplings

Flanges

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• In industrial, commercial, and institutional applications, the most commonly used flanges conform to the requirements of ASME B16.5 and ASME B16.47.
• The purpose of the flange is to remove easily as one side is bolted.
• Pressure classes of cast iron flanges are established in ASME B16.1.
• These flanges are available in a variety of styles and pressure classes.
• Flanges are not recommended for use in underground service.
• If it is required to use a flange, the connection is exposed in a valve pit for maintenance access.
• Pipeside is always welded or threaded, and the other side is bolted.
• The number of bolts used to join any standard flange pair is always divisible by four.
• Flanges may be joined with either hex head bolts or studs nutted on each end.

Elbows

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• They provide piping systems flexibility and are utilized to get past obstructions.
• They are the most commonly used fittings.
• Similar to flanges, elbows and other steel fittings can be purchased with ends that are appropriate for threading, socket welding, or butt welding.
• Flanged ends are also available for cast and ductile iron elbows.
• There are two types based on angle 
  1. 90° Elbows
  2. 45° Elbows

Short radius (SR)

• Elbows are generally only used where space constraints prevent the use of long radius elbows.
• They are only available in 90° bend.
• Short radius elbows have a takeout dimension equal to 1D where D is the nominal diameter of the pipe.

Long radius (LR)

• Elbows have a takeout equal to 1½ D.
• Long radius elbows are available in 90° or 45°.

Tees

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• Tees are used to form a branch connection in the existing lines.
• They are divided into two types based on the connection pipe size
  • Equal TEE: 
  • Reducing TEE: If the size of the branch is the same size or one or two sizes smaller than the run pipe, then a tee or reducing tee.
• Installing a butt-weld tee made as per ANSI B16.9 ensures that the joint can handle the same pressure as the connected pipe, with no need for extra pressure calculations.

Reducers

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• In piping systems, a reducer is a pipe fitting that joins two pipes of differing sizes.
• Whether the pipe size is increased or decreased, it permits a seamless change in flow.
• Reducers lessen pressure loss, avoid turbulence, and maintain appropriate flow conditions.
• In process sectors where flow rate, pressure, and equipment connections change, such oil and gas, power plants, and chemical plants, reducers are frequently utilised.
• They come in a variety of materials, including alloy steel, carbon steel, and stainless steel, and are produced in compliance with ASME B16.9 for butt-weld fittings.
• For system safety and efficiency, the kind and orientation of the reducer must be chosen carefully.

Two primary categories of reducers exist:

• Concentric reducers, which are utilised in vertical pipe systems, have the same centerline at both ends.
• Eccentric reducers are offset endpoints that stop fluid or air buildup.

Unions

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• A pipeline union is a type of fitting used to connect two sections of pipe, allowing easy assembly and disassembly without causing deformation.
• Unlike welded or flanged joints, unions can be installed or removed quickly, making them ideal for systems that require regular maintenance or replacement.
• Typically, a union consists of three parts: a male end, a female end, and a central nut that holds the ends together.
• They are commonly used in low-pressure piping systems and are available in materials like carbon steel, stainless steel, and brass. U
• Unions ensure leak-tight connections and ease of access in confined spaces.

Caps

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• Cap fittings are used in piping systems to seal the end of a pipe, preventing the flow of fluids or gases.
• They are typically installed at the end of pipelines or unused outlets to ensure safety, prevent leaks, and allow for future extensions if needed.
• Pipe caps are available in various shapes, such as hemispherical or elliptical, and are made from materials like carbon steel, stainless steel, or plastic, depending on the application.
• These fittings are manufactured to standards like ASME B16.9 for butt-weld caps or ASME B16.11 for threaded types.
• They are essential in both high- and low-pressure systems.

Nipples and couplings

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• Nipples and couplings are essential pipe fittings used to connect straight pipe sections, adapt to different sizes, or facilitate changes in direction and flow.
• A nipple is a short length of pipe, usually threaded at both ends, used to connect two other fittings or valves.
• It comes in various types such as close nipple, hex nipple, and long nipple, depending on length and application.
• Nipples are commonly used in piping and low-pressure piping systems.
• A coupling, on the other hand, is a fitting that joins two pipes together in a straight line.
  • It can be full (joining same-size pipes), half (joining pipe to a fitting), or reducing (connecting different diameters).
  • Couplings are available in threaded or socket weld forms, and are made from materials like carbon steel, stainless steel, brass, or PVC.

Both fittings are widely used in domestic, industrial, and chemical piping for their simplicity and reliability in joining components.