UG-27 Thickness of shells under internal pressure 1

[takio]

Hello,

Could anyone help me with this question?
I appreciate it in advance!

What calculation has to be considered?
There are two types of stresses
1) Circumferential stress (longitudinal joints)
2) Longitudinal stress (Circumferential joints)

The way I understood this is that I have to choose one of them depending on how the shell is welded between longitudinal joints and Circumferential joints. or when Circumferential joint efficiency is less than one half of longitudinal joint efficiency.
What if the shell is not welded? Should I go for Circumferential stress?
and what if P > 0.385SE for circumferential stress, and P < 1.25SE, but the joint is welded longitudinally?

Thank you!

 

[XL83NL]

Need them both. Not all loads come from pressure. Think of long, tall and small towers with wind loads. Or long vessels with ears on which they hang. They add stresses to the long. stress component, which normally is about half the circ stress, but all of a sudden increases.
For the second question, one goes to appendix 1 calculations.

 

[DriveMeNuts]

Both hoop and longitudinal directions need to be considered separately, because each has different NDT requirements.

 

[FormerAIS]

Both required, as stated above.

The shell will still need calculations (both of them) without a weld seam because the stress is still present. The Code makes considerations for this scenario.

Quality is not an act, it is a habit - Aristotle