Scope
This method supports half-pipe jackets attached to a shell or head with a thickness between 3/16” (19 mm) and 2” (50 mm) inclusive. The half-pipe is limited to NPS 2, NPS 3 and NPS 4. There must be positive pressure in both the vessel and the jacket. The method has some consideration for external loads on the shell or head; but not on the jacket.
Method Basis
The calculations are based on ASME Section VIII, Division 1 Appendix EE and Section VIII, Division 2 4.11.6. These methods are essentially identical. The only difference is that Division 1 provides figures that a user may read to obtain the K value and Division 2 instead provides curve fit equation for these curves to determine the K value. This method uses the curve fit from Division 2 in all cases as it provides better standardization and is therefore easier to explain and justify to third party reviewers.