How to model a flanged cross pipe fitting with center of cross to face of flange measurement = 1 foot?
There are 2 methods of creating a Cross piping component in AutoPIPE
1. Model using Cross component
2. Model using back to back Tee components - click here for modeling approach
Creating a flanged cross in AutoPIPE is easy with a cross component.
A. Select a node point in the model
B. Use insert Tee command
Length = 1 ft
Tee Component = Cross
Press OK to continue
C. Insert other end of Cross piping on header by using insert Run command, Length = 1 ft.
D. Note what is the current segment name is (ex. Segment A). Now, select one of the Blue arrows that is pointing away from the last node point (ex. A02) so that it becomes a red arrow.
E. Use insert Run command, specify direction of branch pipe and Length = 1 ft.
Press OK to continue.
F. Select remaining blue arrow so that it turns red.
G. Again, select insert Run command, specify direction of branch pipe and Length = 1 ft.
H. At this time the following warning will be displayed.
This Warning tells that the current General Model Options Piping Code selected does not have an SIF calculations for a Cross component. The user must enter a custom value by re-opening the Cross component dialog. See Type of tee = Other.
Note: Even if you have input the SIFs for the cross, this warning will continue to appear in the Model Consistency check. It is not an error and will not prevent the program from running. It is there to remind people that a user SIF value is required for that point.
Select the Type of tee drop down listing and re-select Other again. New boxes will open for "SIF-In " and "Out". These will have to be updated manually as the default values are wrong. Most piping codes (i.e. ASME B31.1, B31.3, etc..) do not have SIF calculations for cross fittings. Only available options are: A. hand calculate the SIF value using other reference materials B. contact the manufacture to have them supply an SIF value, or C. analyze with an FEA application to provide the calculated value based on the cross's geometry.
Again, Enter in the appropriate values and press OK to continue.
I. Continue to insert additional piping as required.
J. Insert flanges by first select the 4 node points where flanges are to be inserted.
K. Use insert Flange command, specify flanges as needed and press OK to complete the command.
Note that the cross element should have all four legs in one plane. If the four legs do not lie in one plane, AutoPIPE will not be able to determine the in-plane and out-of-plane directions for code stress calculations. To avoid this problem, when the legs are in different planes, it is recommended to insert two adjacent tee points, instead of a cross.
Tee, Cross, or Branch Piping Components - Modeling Approaches