The latest revision of B31J, which is currently in draft mode, introduces new formulations for stress intensification factors (SIF’s) and flexibility factors (k’s) for various branch components. This paper explores the background of the work that has gone into the latest B31J document, draft revision 12 – 2015. Trends based on different geometric parameters are presented with respect to how conservative or non-conservative the current (2014) B31.3 Code is versus the data which serves as the basis of the new B31J formulations. Eliminating non-conservative evaluations will help eliminate the small subset of piping systems that likely do not provide the Codes’ intended separation between design and failure. More importantly, eliminating overly-conservative evaluations will reduce the material and man-time costs associated with larger diameter piping systems (8"NPS and larger and D/T>15). It is believed that this cost savings, and reduced need for unnecessary rerouting will be the most significant benefit realized by the implementation of B31J. Just as with WRC 329 three decades earlier, B31J also recognized a number of additional deficiencies beyond the current alignment scope caused principally due to changes in manufacturing, quality control and testing. Future revisions of B31J will hopefully continue to support a uniform, practical, and safe design environment for piping systems.
Proposed Updates to Appendix D SIF and K-Factors for Branch Connections
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Becht, C, V, Paulin, A, & Stonehouse, M. "Proposed Updates to Appendix D SIF and K-Factors for Branch Connections." Proceedings of the ASME 2016 Pressure Vessels and Piping Conference. Volume 3: Design and Analysis. Vancouver, British Columbia, Canada. July 17–21, 2016. V003T03A023. ASME. https://doi.org/10.1115/PVP2016-63691
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