| Applies To | |||
| Product(s): | AutoPIPE, | ||
| Version(s): | ALL | ||
| Area: | Flange analysis | ||
| Original Author: | Bentley Technical Support Group |
Dec 2014, AutoPIPE V8i 09.06.01.10
Problem:
Even with "zero loads and moments"; still AutoPIPE's Flange analysis results says the connection fails, if this were true it would not be possible to create a connection with these characteristics, which contradicts the reality because it is based on a specification of their client which has been widely used for different services and for many years. Why is the results failing?
Solution:
Open the Flange report (*.FLR can be opened by any text editor, i.e. NotePad, Ultra Edit,etc..) and scroll down to the location where the flange is failing, asterisk next to values,
Scenario #1:
The flange is not failing but it is the Gasket seating condition that is failing.
In all cases it's the stresses at the gasket that are failing during the Longitudinal Hub Stress calculation. The allowable is only 30.000 ksi and the gasket stress were calculated by code equations to be 33.700 ksi.
AutoPIPE is performing the code calculations mentioned in ASME III Appendix XI - 2010 correctly. In conclusion, this flange with these settings does not pass and requires changes in order to satisfy the code Gasket Seating Condition for Longitudinal Hub Stress.
Scenario #2:
In this scenario, more information is available under section "6.0 Errors or Warnings",
Therefore the flange is failing on Bolt tensile stress which is ultimately attributed to the calculated Bolt spacing.
AutoPIPE is performing the code calculations mentioned in ASME III Appendix XI - 2010 correctly. In conclusion, this flange with these settings does not pass and requires changes in order to satisfy the code Bolt Spacing and Bolt Spacing correction factor.