Non-Circular Nozzles & Mandatory Appendix 13 of ASME BPVC, Sec. VIII, Div.1

[XGI_451]

Has ASME ever provided a Code Case or Interpretation that allows Obround Nozzles to be designed per Appendix 13.

 

[Cobra17]

there is an interpretation, but you won't like it. (question 2)

Standard Designation: BPV Section VIII Div 1
Edition/Addenda:
Para./Fig./Table No:
Subject Description: Section VIII-1, Appendix 13, Obround Pressure Vessels
Date Issued: 10/22/1985
Record Number: BC84-591
Interpretation Number : VIII-1-86-23
Question(s) and Reply(ies):

Question (1): Appendix 13, 13-11(b), states that all reinforcement members have the same moment of inertia. Is it permissible to design a vessel with reinforcement members having differing moments of inertia, provided the minimum moment of inertia is used for all calculations?

Reply (1): No.

Question (2): A short, obround pressure vessel member (nozzle) is reinforced at one end by a welded-on flange which follows the contour of the vessel member, and at the other end by passing through the vessel wall, where it is also welded. May this be designed using the rules of 13-11?

Reply (2): No.

Question (3): 13-11(b) states, "For any other type of reinforced obround cross section vessel, see U-2 ." Does this apply to an obround nozzle?

Reply (3): Yes.

Typically you just use the larger diameter and consider it a circle.