LPZ74
Mechanical
- Jan 21, 2003
- 11
Fellow Engineers,
Firstly, I apologize if this becomes a long question...
I currently have the task of reviewing a Vendors Code calculations for an ASME Div VIII pressure vessel operating at 515 kPa (75psi) and 160 degrees Celcius. The Vendor previously had selected a shell thickness of 15mm and has ordered the plate. Unfortunatley, they did not perform all the required nozzle calculations (i.e. WRC 107), and since performing these calculations, they have realized that the nozzle is not adequatly reinforced.
Their solution is to add an additional re-pad to the existing one. So, what they currently have is a 34" nozzle inserted into a shell of 15 mm thickness with a repad of 15mm thickness (sketch b-1, Fig UG-40) PLUS a 6mm repad on top of the existing repad. Is this allowed? I have looked UG-37 and through Figures UG-40, but do not see a similar nozzle configuration to what they are proposing. Can anyone out there tell me if this is an acceptable solution?
Also, is there a limit to the maximum thickness that a repad can be (dimension te) in relationship to the thickness of the vessel. Previously I had always thought that the thickness of a repad should be less than or equal to the thickness of the vessel. Is this just good practice or is it a code limit?
Thanks and Regards,
lpz74
Firstly, I apologize if this becomes a long question...
I currently have the task of reviewing a Vendors Code calculations for an ASME Div VIII pressure vessel operating at 515 kPa (75psi) and 160 degrees Celcius. The Vendor previously had selected a shell thickness of 15mm and has ordered the plate. Unfortunatley, they did not perform all the required nozzle calculations (i.e. WRC 107), and since performing these calculations, they have realized that the nozzle is not adequatly reinforced.
Their solution is to add an additional re-pad to the existing one. So, what they currently have is a 34" nozzle inserted into a shell of 15 mm thickness with a repad of 15mm thickness (sketch b-1, Fig UG-40) PLUS a 6mm repad on top of the existing repad. Is this allowed? I have looked UG-37 and through Figures UG-40, but do not see a similar nozzle configuration to what they are proposing. Can anyone out there tell me if this is an acceptable solution?
Also, is there a limit to the maximum thickness that a repad can be (dimension te) in relationship to the thickness of the vessel. Previously I had always thought that the thickness of a repad should be less than or equal to the thickness of the vessel. Is this just good practice or is it a code limit?
Thanks and Regards,
lpz74