Pressure Vessels Design

For example, external pressure applies when the inside of the vessel is in partial vacuum while the outside is at atmospheric pressure (such as some refrigerant vessels), or the vessel is submerged with external water pressure (such as a submarine). In general, whenever P_ext > P_int.

Thank you Tornado for your comment.

My problem is a vessel storage for oil. I ask? can i consider external pressure for my Pv-Elite Design if Pint = Pext = Atmospheric pressure?

ASME VIII Div1 explain this condition or not?

Thanks for All.

KBBR.

If P_ext = P_int, why would it be classed as a pressure vessel? It sounds more like an atmospheric tank, which must resist the pressure of the liquid therein.