This posting (November 2019) is an update to an October 2013 post which reflects changes to the ASME B31.3 Code relative to severe cyclic service that have occurred since the original post. There has been a fair amount of confusion as to when the rules for severe cyclic conditions in ASME B31.3 should be used, […]
The analysis procedures in the Code essentially assume that the strain range in the system can be determined from an elastic analysis. That is, strains are proportional to elastically calculated stresses. The stress range is limited to less than two times the yield stress, in part to achieve this. However, in some systems, strain concentration […]
FCC’s are complex units – and the design of their transfer lines has some unique considerations. While many of the lines are refractory lined to permit construction with carbon steel piping, some sections are hot walled, at temperatures well into the creep range, for the purpose of balancing thermal expansion or, in the case of piping […]
Changes in steelmaking practice are reported to be causing some carbon steel piping components that are assumed by ASME Codes to behave in a ductile manner at ambient temperatures, to behave instead in a brittle manner. Barry Messer from Fluor made a presentation on this subject at the Spring 2016 meeting of the ASME B31.3, […]
If the behavior of discontinuity stresses due to pressure is not properly understood in elevated temperature design, unconservative designs can result. One particular issue with pressure stresses is the behavior of the discontinuity bending stresses. An example of discontinuity stresses would be with a pipe welded to a flange. When pressured, the pipe will radially […]
Appendix P was written to introduce piping flexibility analysis rules that are more suitable for computer piping flexibility analysis, in contrast to the rules in the base Code which were written when piping analysis was done by hand calculations. Most of the elements of Appendix P have been, or are proposed to be, added to […]
Pressure thrust is present in all pressurized piping systems. It is simply the gage pressure times the inside area of the pipe. It acts at changes in direction, such as elbows, and at changes in pipe cross section, such as reducers. Pressure thrust is normally carried as an axial load by the pipe. However, inclusion […]
Bellows vendors will often quote two different cycle lives for their bellows. One is in accordance with ASME B31.3, Appendix X. The other is in accordance with the Standards of The Expansion Joint Manufacturers Association. The latter provides a significantly higher cycle life. The EJMA bellows fatigue curve is a best fit curve based on […]
The simple answer to this question is they should be used when the owner selects the use of these rules for a particular piping system. Note that the definition of High-Pressure Fluid Service simply requires that the owner specify use of Chapter IX. However, it is probably useful to understand why such a selection may […]
I was asked to participate in an engineering career development panel session at the 2013 ASME Pressure Vessel and Piping Conference which was held in Paris, France. I elected to talk about what engineers can do to improve their leadership skills. I am including some of the introductory material in this blog; the full presentation […]
