Section VIII, Division 2, Part 4.5.17

[OnG_Engr]

All,
I am designing a vertical vessel which has nozzles with inner diameters that are more than 25% of the vessel ID. Is there a way to build a vertical vessel with large openings (>25%) without using Part 5?

 

[Soave]

Dear

Have you read ASME VIII Div.1 Mandatory Appendix 1 - item 1.7 LARGE OPENINGS IN CYLINDRICAL AND CONICAL SHELLS?

 

[OnG_Engr]

Apologies. I meant Part 5 of Section VIII, Division 2. I would like to design a vertical Division 2 vessel without using FEA.

 

[TomBarsh]

If you're designing to ASME VIII-2, Part 4, then there is no alternative analysis for openings > the 25% rule. IMO, this is based on the analysis method used for allowable longitudinal compression and combined loads, rather than being directly related to the nozzle opening method.

A lot of designers are using Code Case 2695 to use the Div 2 rules in Div 1, especially for large openings now that Appendices 1-9 and 1-10 have been removed from Div 1. But then their designs fall afoul of the 25% rule. A problem.

 

[TGS4]

There's a reason that you need Part 5. This situation is complicated, mostly because buckling failure is complicated.