On Design Verification of Piping Supports Under Combined Stresses

In this paper design verification rules for piping supports under combined stresses according to ASME NF and its appendices are reviewed and examined in detail. A comprehensive study on these rules for piping supports constructed using austenitic steel will be conducted for service limit levels A, B, C and D. Ongoing projects in Sweden will be used to address the application of these rules and to discuss the design philosophy embedded in ASME III, and its rationality in practical design. We show that the rules specified for service limit level D enforce a stronger design requirement than those specified for service limit level C, which is irrational and inconsistent with the general principle upon which ASME III is built. Our suggestions for improving these rules will be given.