I regret to say that I don't have access to the full ASME VIII Design Code and haven't read Appendix S. I do have ASME PCC-1 and have been reviewing that today. As such I have seen the guideline relating to a proof load of 40-70% of yield stress. The torque required to achieve the designed gap...
Thanks for your replies.
The bolt pre-stress required was around 90ksi the flanges were well over-loaded. We have decided to use standard asme torques and target a larger gap in order to protect the non-standard Appx 2 flanges.
I have an application involving a special flange (based on ASME 16.5 1500lb) which has a spacer in the flange pair. There are ring type joints either side of the spacer. The problem I have is that very high bolt torques (and preloads) are required in order to achieve the 3mm offset at each ring...
