B16.5 Flange Torque 3

[MalcolmA]

I am trying to calculate a torque for bolts on a B16.5 flange. When I use the section VIII appendix 2 calculation for flange stress, I can only put a small stress on the bolts (about 25% of yield). Beyond this load the flange is overstressed due to gasket seating stresses.

We routinely torque bolts to 60% of yield with no leakage or distortion problems.
Are appendix 2 calculations applicable to B16.5 flanges? Has anyone ever run into this problem?

I would greatly appreciate any insight or advice.

 

[TGS4]

Check out ASME PCC-1. It will provide the guidance that you seek.

 

[jte]

Malcolm-

In addition to TGS's advice on PCC-1, I'd suggest you read VIII-1 Appendix S. In this appendix they make it clear that the allowable stresses for bolting are for design purposes and ...it is evident that an initial bolt stress higher than the design value may and, in some cases, must be developed in the tightening operation, and it is the intent of this Division that such a practice is permissible...

jt