Features of Flanges: Designs and Considerations

Flanges are optimum solutions for linking a wide range of pipe systems with the numerous valves, equipment, and other machineries of almost any processing system, flanges are the second most used joining method after welding. Flanges improve flexibility when sustaining piping systems by permitting for easier disassembly and improved access to system components. A typical flanged connection consists of three parts namely pipe flanges, gasket, and bolting. In most cases, there is exact gasket and bolting materials made from the same, or sanctioned materials as the piping components to connect. Flanges are not a one-type-fits-all sort of solution. Sizing aside, matching the ideal flange design to your piping system and planned usage will help to guarantee dependable operation and a long service life.

The most common flange types available: WELDING NECK FLANGES (WNRF), BLIND FLANGES (BLRF), SLIP ON FLANGES (SORF), SOCKET WELD FLANGES (SWRF), LAP JOINT FLANGES, SCREWED/ THREADED FLANGES, SPECTACLE BLIND FLANGES, SPADES AND RING SPACERS, SQUARE FLANGES, ORIFICE FLANGES, RING TYPE JOINT FLANGES (RTJ), PLATE FLANGES, REDUCING FLANGES, ANSI/ ASME B16.5 FLANGES, BS 10 FLANGES, DIN FLANGES, EN 1092-1 FLANGES, AND JIS FLANGES.

Making The Connection: Flange Facing Types

Face types are another distinctive point crucial in final performance and service life of your flanges. Facing types determine both the gaskets needed to install the flange and characteristics related to the seal created. Common face types include: Choosing between the options is important as they will determine the optimal gasket for a reliable seal.

  • Flat Face (FF)
  • Ring Joint Face (RTJ)
  • Male & Female (M&F)
  • Tongue and Groove (T&G)

Common considerations include

  • Thickness: A measure of the thickness of the outer attaching rim.
  • Bolt circle diameter: The distance between opposing bolt holes when measured from centre to centre.
  • Outside diameter: The distance between two opposing edges of the flange face.
  • Nominal bore size: A measurement of the flange connectors’ inner diameter.
  • Pipe size: A designation of the pipe size with which the flange corresponds.

Flange Classification & Service Ratings

Flanges are regularly classified based on their ability to endure temperatures and pressures. This is designated using a number and either the “#”, “lb.”, or “class” suffix. Common classifications include: 150# / 300# / 600# / 900# / 1500# / 2500#

Point to be noted here is exact pressure and temperature tolerances will vary by materials used, flange design, and flange size. In all cases, pressure ratings decrease as temperatures rise.

Flange Dimensions

Flange dimensions are the important factor to influence flange choices apart from the functional design of a flange, when designing, maintaining, or updating a piping system. You must think through how the flange interfaces with the pipe and the gaskets in use to ensure proper sizing.

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