Hello again Charlie

If the flange has a tongue and groove type gasket, then it can be designed in accordance with ASME VIII, Division 1, Appendix 2. In this case you have to decide if it is an integral (weld neck), or ring type flange.

In PVElite, select a flange component from the icons on the top of the screen, then at the bottom of the screen, check the box that says 'perform flange calculation'. When the flange dialogue screen opens up, choose the most suitable type of flange from the thumbnail sketches at the top of the screen.

For a tongue and groove design, you have to enter the 'nubbin' (the tongue) inside and outside diameters. However, by using the 'F1' key when your cursor is in various fields, you will get help on what the various dimensions are.