types of flange

Pipes are one of the components that we often encounter in industry, especially in process industry. The use of pipes in industry is very much in number so it is necessary to have a pipe connector. One of the equipment used to connect pipes is a flange.

Flange installation is the most widely used joining method after welding method. Flange is a reliable tool for connecting one pipe to another or connecting it to various equipment, valves and other components of almost any processing system. The use of flanges adds flexibility when maintaining a piping system with easier assembly and better access to system components.

The flange connection consists of three components namely: flange, gasket, and bolt and is installed together. Special controls are required to select and apply all flange elements to obtain an acceptable leak-tight connection.

Flange components. Source: https://www.pipelinedubai.com/what-is-a-flange.html

The Most Common Types and Characteristics of Flange

Common types of flange. Source: https://www.unifiedalloys.com/blog/flanges-101/

Threaded Flanges. Also known as threaded flanges. This model has a thread in the flange hole that fits into a male thread that fits into the pipe or fitting. Threaded connections can reduce welding in joints. Just match the thread to the pipe you want to connect.

Slip-on Flanges. Silp-on are very common and are available in a variety of sizes to accommodate systems with high flow rates. Simply match the flange to the outside diameter of the pipe you wish to connect. The installation is a bit more technical as you will need fillet welds on both sides to secure the flange to the pipe.

Lap Joint Flanges. Featuring a two-part design, Lap joints require welding from the end of the stub to the pipe or mounting using supports to create flanged joints. This design makes this type popular for use in systems with limited physical space or systems that require frequent disassembly and maintenance.

Weld Neck Flanges. Like lap joints, weld necks require welding for installation. Its performance in systems with multiple repeated bends and its reliability in high pressure and high temperature systems make it the top choice in process piping systems.

Blind Flanges. Used to terminate or isolate piping systems. The blind flange is basically a blank disc that can be bolted on. When properly installed and combined with the correct gaskets, flanges can provide a strong seal but are easily removed when needed.

In addition to the type of flange design, the type of face is another characteristic that will have a major impact on the performance and life of the flange. The type of face can determine the type of gasket and the characteristics of the seal used.

Common types of face

Examples of face types on flange. Sources: https://hardhatengineer.com/types-flanges-used-piping/
  • Flat Face (FF)
  • Raised Face (RF)
  • Ring Joint Face (RTJ)
  • Tongue and Groove (T&G)
  • Male & Female (M&F)

The Classification of Flange Types Based On The Ability To Withstand Temperature And Pressure

It is specified using a number and a “#”, “lb”, or “class” suffix. These suffixes are interchangeable but will vary by region or vendor. The classification is as follows:

  • 150#
  • 300#
  • 600#
  • 900#
  • 1500#
  • 2500#

Exact pressure and temperature tolerances will vary according to the material used, flange design, and flange size. The only thing that is constant is that in all cases the pressure value decreases as the temperature increases.

The flange is below the global standard set by the American Society of Mechanical Engineers (ASME) – ASME B16.5 & B16.47. If you are trying to replace or verify an existing part, the flange must include a marker.

Standard offers a solid foundation on the basics of flange design and how to select the ideal flange for your piping system. However, with the wide variety of stainless steel flanges and other flange materials available, it is impossible to list every configuration, detail, or consideration.

Contributor: Daris Arsyada

By Caesar Wiratama


https://www.unifiedalloys.com/blog/flanges-101/ (accesed in May 15 2021)

https://blog.projectmaterials.com/flanges/flange-types-piping/#:~:text=The%20key%20types%20of%20flanges,reducer%20flange%2C%20and%20orifice%20flanges.  (accesed in May 15 2021)

https://hardhatengineer.com/types-flanges-used-piping/  (accesed in May 15 2021)

https://www.pipelinedubai.com/what-is-a-flange.html  (accesed in May 15 2021)

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