ASME Sec 8 Div 1 Code Case 2260 1

[NewfieEng]

I am trying to re-rate a pressure vessel from 550 up to around 600 psig, but the maximum MAOP from the standard code calculation is 551. But if I do the calculations using the Code case 2260 I can get 590 psig. The Maximum pressure is restricted due to the ellipsoidal head on each end, which has no attachments. Code Case 2260 use a coefficient of 3.5 instead of the standard calculation coefficient of 4, this is how I get a higher MAOP.

My question is under what circumstances can I use Code case 2260 for doing my calculations? And what restrictions are there on this code case? I do not have the latest version of ASME Sec8Div1, so I have no information on this case.

NewfieEng

 

[metengr]

NewfieEng;
Are you attempting to re-rate an in-service vessel?

 

[NewfieEng]

Yes it is a vessel that is pressently in service but we would have to remove it to perform the needed hydro test for rerating. It is currently not operating at the higher pressure but may see the higher pressures in the future.

 

[metengr]

NewfieEng;
Re-rating of in-service pressure vessels typically falls under the requirements of the National Board Inspection Code (NBIC). Please obtain a copy of this code book and review the requirements for re-rating. ASME Code Cases typically apply to new construction and would not be used for re-rating in-service vessels.

 

[spayette]

We have done literally hundreds of rerates for our client who has mandated the use of API-510 rather than NBIC. If your facility has adopted the same authority then Section 7 and in particular Figure 7.1 of that document will answer whether or not you can use the new code allowables for the particular vessel that you are considering for a rerate.

 

[NewfieEng]

Thank you for the replies.
I am planning to not rerate the vessels and make do with the vessels that we have in service. We may just build new vessels in the future.