| Applies To | |||
| Product(s): | AutoPIPE, | ||
| Version(s): | All | ||
| Area: | Settings | ||
| Original Author: | Bentley Technical Support Group |
Comments, Questions, and Answers related to Tools>Model Options> Results> "Use nominal thickness" setting in AutoPIPE:
Item #1:
Why does mill tolerance not effect sustained stresses in AutoPIPE calcs for ASME B31.3?
Answer:
Select Tools> model options> Results> and press the "Help" button in the lower right corner of the dialog. From this point, select the hyperlink for "Use nominal thickness ". On this page is a chart that shows what wall thickness is used for which code calculations. For ASME B31.3, per Stress Category = Sustained, when this feature is checked On; Tnom is used, when this feature is checked Off; Tcor is used. If you go to the Definition of Terms page in AutoPIPE to look up these definitions:
tnom = Nominal wall thickness of the pipe.
tcor = Corroded wall thickness of the pipe (= tnom - c).
As you can see the mill tolerance does not come into play for the calculation of Sustain stress code calculation.
Furthermore, take a moment to search the actual code for "Mill Tolerance" to see exactly where it is being used.
Item #2:
For Stoomwezen this setting is off by default and for EN13480 it is on by default. Is this difference in default settings a code requirements or not?
Answer:
Each piping code has requirements for what wall thickness would be used in a specific calculation. The CAE development team automatically adjust many default setting based the piping code selected. In this case, please see the following AutoPIPE help section: Help > Contents> Contents Tab> Reference Information> Code Compliance Calculations> En1380 and Stoomwezen,
Stoomwezen:
Stresses Due to Sustained Loads (STOOMWEZEN)
Noticed that the value tred or corroded thickness is used. Another words "Use nominal wall thickness" by default should be OFF .
En13480:
Stresses due to Sustained Loads (En13480 - 2012)
Notice that the value en or nominal wall thickness is used. Another words "Use nominal wall thickness" by default should be ON
Again default setting are usually based on code requirements.