Conical tank bottom thickness evaluation 1

[rc1962]

API 653 does not address conical bottoms but as we know, they are built with them. I was told to go to ASME Sec VIII and use the formula there. My question is, what do you use for pressure? Do you use static head of the height of liquid of atmospheric? Thanks in advance for any help.

 

[JStephen]

What was the original design standard? API-620 includes suspended bottoms.