Thick vessel criteria

[khati]

Hello,

Can anyone tell me how do we define thick vessel, means above what thickness do we tell the vessel is thick. (please give reference of the ASME code).

regards

 

[Fizza453]

Khati,

ASME Section VIII-1 takes the cylinders into two categories.

1- When thickness does not exceed one half of the inside radius or pressure does not exceed 38.5% of the shell allowable working stress times the joint efficiency, for such cylinders UG-27 formulas are applicable.
2- When thickness does exceed one half of the inside radius or pressure does exceed 38.5% of the shell allowable working stress times the joint efficiency, for such cylinders formuals of Appendix 1 are applicable, see 1-2 (page 373, edition 2010).These formulas may also be used for category 1 cylinders.


In ASME Section VIII Division 2, there is not such a boundary.
Hope it helps.


Nasir
Welding Engineer
DESCON ENGINEERING LIMITED
PAKISTAN