@doct9960
With regards to calculating rotation of flange, the rigidity factor formula in ASME VIII Table 2-14 can be modified to do just this. By simply removing the K factor the result will be rotation in degrees.
So in essence, ASME VIII rigidity limits rotation on integral flanges to 0.3 degrees and rotation on loose-type flanges to 0.2 degrees. This is obviously based on allowable bolt stress however and in the real world the rotation will be higher than this.
For PCC-1 Appendix O, we typically limit flange rotation to 1 degree for spiral wound (and similar materials).