Home technical Fundamental’s of pipes and fittings

Fundamental’s of pipes and fittings



Pipes and fittings Selection needs careful attention. Piping is the conduit that transports any fluid whether it’s water, oil, gas, beverage, crude oil, sewage water, steam, and lots of more utilities from one place to another. Piping is laid down above ground, underground. It is also laid down under the ocean to move crude petroleum between the two countries. It transports the fluid under pressure and temperature. Depending on the pressure, temperature, and nature of the fluid different materials of construction (MOC). of piping’s are used. Pipes and fittings Selection is very important for our industrial and domestic sectors. Pipes and fittings Selection may affect our plant reliability and productivity.

Piping must be selected, installed, and tested carefully to avoid pre-mature failure. Also, the periodic check-up of the piping to be administered to prevent any failure from happening. Failure in the piping may hamper the production in our factories. It also hampers the availability of utilities for the community. Apart from piping, fittings are also a crucial component of the piping network. Piping usually goes in one direction however, the fittings are used to change their direction and facilitate them to connect with one another. They also create the pliability to change damaged piping in parts when required. Piping and Fittings both together form a Piping network.

Depending on manufacturing methods, piping is categorized as follows:

(1) Electric Resistance Welded pipes (ERW)

(2) Electric Fusion Welded pipes (EFW)

(3) Seamless pipes (SMLS)


ERW pipe is manufactured from a coiled metal sheet. The metal sheet is made into a cylindrical shape by cold forming. Then the current is passed through the butt edges of the cylindrical sheet. The warmth produced by the resistance of current flowing through the coiled sheet is used in the welding of the joint by application of pressure. No filler metal is used in the production of ERW Pipes. ERW pipes are utilized in low-temperature applications. They’re mainly used for water, fencing, agricultural, and scaffolding services. ERW pipe production is explained in the following fig.

Pipes and fittings Selection deals ERW
Pipes and fittings Selection deals ERW


These pipes having longitudinal welding. Coalescence is produced in the formed metal tube by manual or automatic arc welding. The welding could also be single or double and should be with or without filler metal


Seamless pipe is manufactured by piercing a hot billet with mandrel followed by rolling or drawing process or both. Seamless piping is used for high-pressure and high-temperature applications. Various piping materials are available for various services in domestic as well as in industrial sectors are as follows


(1) Galvanized Iron (GI), for water

(2) Cast Iron (CI), for raw water

(3) Polyvinyl Chloride (PVC) for water and plumbing

(4) Chlorinated polyvinyl chloride (C PVC) water and plumbing

(5) Chrome brass for plumbing

(6) Chrome copper for plumbing


(1)Carbon Steel

(2)Alloy Steel

(3)Stainless Steel

ASME and ANSI (American Society of Mechanical Engineers and American National Standard Institute) have formed the dimensional standard to follow while manufacturing piping from the above material:

ASME/ANSI B 36.10, for Welded and Seamless Wrought steel pipes

ASME/ANSI B36.19, for stainless steel

These standard includes: Inside diameter(mm), outside diameter(mm), wall thickness(mm), schedule no, pipe weight(kg/m) and water weight(kg/m)
These standards are meant for high and low and Temperature and pressure.

ASME has developed code B 31 for pressure piping and fittings for various services. They include design procedures, MOC( Material Of Construction), fabrication methods, testing procedures, inspection stages, operation, and maintenance. of piping. Under B31 different sections are there for various services as follows:

(1)B31.1 for Power Piping

(2)B 31.3 for Process Piping

(3)B 31.4 for transportation of liquid hydrocarbons and liquids

(4)B31.5 for Refrigeration Piping

(5)B31.8 for Gas transportation and distribution

(6)B31.9 for Building service Piping

(7)B31.11 for Slurry transportation Piping System

(8)B16.11 for Socket Weld Fittings

(9)B16.9 for Butt Weld Fittings


Pipe fittings are the mechanical components to connect the two piping with each other. Pipe and fittings together form the piping system. Elbows are used to change the direction of piping. 90 degrees and 45 degrees elbows are in use. Fittings are manufactured from various materials like steel, iron,  and brass. They are produced by the forging or casting process. The popular material used for fittings manufacture is steel. Fittings are available both in welded and threaded construction. Some fittings provide the straightforward removal of piping for future disassembly.


SW and threaded type fittings are in use as follows:

(1)90-degree Elbow (Equal, SW, and Threaded)

(2)45-degree Elbow (SW type)

(3)Tee (Equal and UN equal, SW and threaded)

(4)Cross(All branches equal)

(5)Couplings(SW and threaded)

(6)Reducer coupling(SW and threaded)

(7)Unions (SW and threaded)

(8)End Caps(SW and threaded)

(9)Plugs (Threaded)


IN ASME B16.11 document threaded and socket fittings are classified for ratings 2000, 3000, and 6000. Further fittings are classified for ratings 3000, 6000, and 9000. These ratings are holding good for NPS(Nominal Pipe Size) 1/8 inch to 4 inches (ca. 10 cm). For large-size fittings ASME standard B16.9 to be followed.

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