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Custom Flange Calculation

The Custom flange calculation page allows you to input the critical dimensions of a Weld neck flange and will provide a minimum required bolt load to seal the flange based on the wm1 and wm2 values from the ASME Boiler and Pressure Vessel code VIII, Div 2, App 3.

Boltup® Custom Flange Calculation

First, confirm the Units you wish to use either mm or inches, then confirm the geometry of flange by entering values for :

  • Flange OD (OD = Outside Diameter)
  • PCD (bolt pitch circle diameter)
  • Hub Diameter
  • Pipe OD
  • Gasket OD. This needs to be the outside diameter of the sealing area of the gasket.
  • Gasket ID. This needs to be the inside diameter of the sealing area of the gasket.
  • Flange Thickness.
  • Flange Height. This is the length between the underside of the flange face to the weld joint with the pipe.
  • Bolt Size. Select your bolt diameter from the drop down box .
  • Bolt Qty. This is the number of bolts in the flange joint.
  • Bolt Material. You may select from the listed bolting materials that appear from the drop down menu. The program will take account of stress relaxation factors due to temperature (when appropriate) as well as strength limitations due to bolt size.
  • Gasket Type. Select the gasket type and the material from the drop down menu.
  • Raised face OD. Enter the diameter of the raised face of the flange (if appropriate), if a RTJ type gasket I selected then this option is not available.
  • Operating and Test pressures. Enter the operating pressure in either Bar or psi. as appropriate. At the same time the test pressure will be calculated based on a factor of 1.5 times the entered pressure. This can be altered if required to suit the particular test conditions.

Click on the ‘Calculate’ button and the ‘outputs’ box will be populated with the minimum required sealing loads and stresses.