ASME Section VIII, Div.1 Appendix 1-4

[johnnymist2003]

Hi all,

for an ellipsoidal head designed to UG-32(d), Appendix 1-4 (f) must be considered when t/L<0.002. 1-4(f)(1)(h)(2) sets limits of 0.0005<=t/L<=0.002. What does one do in the case where one has a large diameter, low pressure dished end, where t/L<=0.0005? Is ASME VIII, Div.1 implying that if t is so calculated that t/L<=0.0005, then some other design code should be used?
Your comments, please.
Thanks in advance.
John

 

[codeeng]

Where t/L < 0.0005 you'll need to perform an analysis of the head (refer U-2 (g)). On very thin, large diameter heads there is a build up of compressive stresses in the knuckle-crown region. I recall seeing some paper about this many years ago. Perhaps someone has a copy ?

 

[Bobfromoh]

It sounds like you are rerating an existing vessel? If this is true, you should go back to the original code of construction. The vessel may not work with calculations from the latest code.
If it's a new vessel then you just need to calculate the thickness needed and specify it in the purchase documents.