Question
How does AutoPIPE Vessel performs the flange calculations as per UG-44?
Answer
ASME Section VIII, Division 1, UG-44 covers the requirements for flanges and pipe fittings in pressure vessels.
Section UG-44 (b) focuses on the evaluation of external loads on welding neck flanges, particularly those connected to nozzles. It provides a method to determine if the flange can withstand the combined effects of internal pressure and external loads (like bending moments and shear forces) without failure or leakage.
Here,
If the Moment Factor checkbox is unchecked, When using ASME design code, values defined by Table UG-44-1 (Div.1) / Table 4.16.12 (Div.2) are used.
Otherwise it is set to zero, a conservative value.
To view the details according to UG-44, navigate to Report > Summary > Summary of Forged Items > Standard Flanges > Evaluation of External Loads.
For Example 1:
When we enter a user defined value of FM = 0 in Nozzle N1, the flange rating will be displayed as 600#.
Similarly when we enter user defined value of FM = 1.2 in Nozzle N1 we will get the flange rating of 300#.
Below are the calculation details. We can understand the calculation through the following three cases.
- Case 1 : The flange rating for Nozzle N1 is 300# with a Moment Factor (FM) of 0, which does not meet the criteria specified in UG-44 (b).
- Case 2 : The software adjusts the rating to 600# with an FM of 0, satisfying the criteria in UG-44 (b).
- Case 3 : Adding a Moment Factor value of 1.2 to the 300# rating also meets the criteria outlined in UG-44 (b).
See Also