Division 2 Rules for Heavy Barrel Nozzles
Using heavy barrel nozzles? Then it may be a great time to consider using the Division 2 rules for your vessel design.
The large shell section removed makes heavy barrel nozzles tough to pass Division 1 Area-of-Replacement rules. Part of the issue is because too much of the heavy barrel ends up outside of the limits of reinforcement. A frustrating result for designers expecting a big advantage from the extra nozzle thickness!
The Division 2 nozzle rules use the Bildy method instead of Area-of-Replacement. This method calculates the nozzle stresses in a completely different manner, which is advantageous for heavy barrel nozzle design. Notice that the exact same nozzle easily passes at the exact same design pressure and temperature.
With the new 2025 ASME Code changes there has never been a better time to begin learning and using the Division 2 rules. Not sure where to start? Let Metalmark Engineering help your understanding of the differences between the Division 1 and Division 2 rules.
Appendix 46 for Large, Non-Radial Nozzles
Don’t let large, non-radial nozzle designs ruin your design schedule. Pass nozzle reinforcement calculations and stay ASME Code compliant by using Appendix 46.
A recent client had a big problem with a large nozzle. The 10’ (3m) vessel diameter and 42” (1m) nozzle diameter pushed the Division 1 nozzle calculations into Mandatory Appendix 1-7. The nozzle design would have easily passed the Appendix 1-7 calculation at the design pressure of 50 psi if it were radial. But it wasn’t. The 2” inch offset was non-negotiable and pushed it outside of Appendix 1-7 due to failing Appendix 1-7(b)(1).
This represented a perfect case for using the Appendix 46 nozzle rules. Appendix 46 combines Division 2 nozzle design rules with Division 1 allowable stresses. The more accurate numerical method combined with the high safety factor gives an ASME Code compliant solution that satisfies most regulators. Ask your regulator about using Appendix 46 as direct-replacement nozzle rules and solve problems like large, non-radial nozzles within minutes without employing FEA.
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