ASME pcc calculation required?

[Ehiman1]

Hello, I checked a girth flange of a heat exchanger in accordance with ASME VIII div1 appendix 2, as per project specification and everything is verified, but if I check the flange with ASME PCC-1 appendix O as well, the verification isn’t ok.
Bolts are not enough to seat the gasket.

In this case ASME PCC calculation isn’t required for the project, but does it mean that this flange will have leakage problems of sure?

There are several projects where PCC is not required and this means to design a flange with lower thickness and bolts with small size with appendix 2 only, but in these cases pcc could be verified or not.

 

[TGS4]

I think that you will need to give some additional details about your situation. I don't know what "bolts are not enough to seat the gasket" means.

 

[Ehiman1]

Step 5 and 6 of paragraph O-4.2 of ASME PCC appendix O isn’t verified.
To solve this we need to increase bolts size to create higher stress on gasket but this involves higher stress on flange and this means to increase flange thickness as well.
At the end, a common calculation with appendix 2 can lead to 3” thickness of the WN flange and 7/8” bolts size.
With ASME pcc appendix O in order to verify step 5 and 6 we need 1” bolts size and 4” flange thickness.
Results are totally different, for this reason I have this question.

 

[GD2]

What is your flange size? Does it fall under ASME 16.47? If yes, How does the App 2 design comes out when you compare with ASME 16.47 dimensions?

App 2 calculation is a bit complex. Even saying that, flange joint design had never been easy. It's still evolving...

GDD
Canada