Applies To Product(s): AutoPIPE, Version(s): 2004, XM, & V8i Environment: N/A Area: Subarea: Original Author: Bentley Technical Support Group Comments, Questions, and Answers about ASME B31.1 Piping Code Calculation Issues Item #1: After changing the piping code edition from 2010 to 2012, the results are different, why? Answer: 1. B31.1 2010 library has different modulus values as compared to B31.1 2012 library, for example compare the pipe material library data from both library files ( B311-10 & B311-12) for CS. This will account for some of the differences observed by the user. 2. Review the Temp / Press/ PipeID tab to be sure that the expansion and modulus values in the model are correct. 3. The ASME B31.1 -2012 code has different material values than listed in the 2010 edition. These changes would effect multiple pipe properties, ex. long, hoop and shear modulus, in the program. 4. In some rare cases (where no consistent steps have been documented in order to repeat), the model data was found to be different when compared to the program's library files. This would cause a significant change in the code compliance calculations. One way to be sure the model has the correct library values is to essentially reset the Library data by using the following procedure: Under Tool model Options General change the ambient temp from the original setting to a different one, press OK button a few times, and then go back to the same location to change it back to the original value. This action will cause the program to reload all the material library data used in the model or refresh the data. Warning: after resetting the library data as described above be sure to validate the Tools Model Options Edit and Results settings are correct. Item #2: Which equation the program uses for thermal stress. There are two equations that address the thermal stress in the power piping code and the process piping code. Both equations are listed in ASME B31.1 Power piping code and B31.3. Process piping code. One is very conservative eq. 1A. The second eq. 1.B. Is much more liberal. The reason i am asking this question is that if your system fails eq. 1A does not mean that the system actually fails until it fails eq 1b. Answer: To the CAE development team, ASME Eq 1b is know as Sustain Load Margin. AutoPIPE has a feature under Tools Model Options Results Sustain Margin that always includes, only includes when needed, or to never be considered in a model analysis. See online help for more details on this feature. If you do not know about these settings, suggest that you take some time and review each one as they are very important to your analysis results. See Also Bentley AutoPIPE External Links Bentley Technical Support KnowledgeBase Bentley LEARN Server Comments or Corrections? Bentley's Technical Support Group requests that you please submit any comments you have on this Wiki article to the "Comments" area below. THANK YOU!
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