scope:

Appendix I1 of ASME Section VIII, Division 1,1977 Edition contains rules for the design of flanges where the gasket is located inside the bolt circle and there is no contact between the flanges comprising an assembly outside the bolt circle. Further, the hub or nozzle is located at the bore of the flange. Hereafter in this paper such flanges will be denoted as "conventional" flanges. Rules are being added to Appendix I1 to cover the design of reverse flanges where the shell is attached to the outside diameter and there is no contact between the flanges of an assembly outside the bolt circle. Fig. 1 illustrates a typical reverse flange. The design procedure for reverse flanges was developed using the basic rules and procedures applicable to conventional flanges modified as necessary to account for the difference in behavior of such flanges.