Indicates one of the following:
For all except lap joints
The inner diameter of the flange face. The software uses the maximum of the flange face ID and the gasket ID to calculate the inner contact point of the gasket. This value is required for calculating the contact gasket width and the effective gasket diameter, G.
For lap joints
The lap joint contact inner diameter. This is usually the flange inner diameter. For additional details, see ASME Section VIII, Division 1, Appendix 2, Figure 2-4, Sketches 1 and 1A.