Minimum design pressure

[mgiani84]

Hi, I´m designing a vessel using ASME VIII and a I want to know if there is a minimum design pressure that I have to consider.

The design pressure of the process is 22 PSI. Can I use 30 PSI or I have to use a bigger value?

Thanks,

MG

 

[stanweld]

If your design pressure is 22 psi, that is the minimum. You may also choose a higher pressure. That's up to you.

 

[gr2vessels]

mgiani84,
For the minimum design pressure, refer to ASME VIII Div 1, Clause U-1(c);- it has specified 15 psi.
The lowest design pressure allowed by the process conditions, including any pressure surges, temperature excursions and other conditions, is the most economical design condition and is good engineering practice to use the process specified design pressure plus a small margin, say 5-10% or even less, to allow for unexpected conditions. The proposed 50% increase in design pressure has to have a good justification, otherwise it contradicts the good engineering practice. If nothing prevents you selecting say, 25 psi design pressure, why would you design for 30 psi or more, increasing the vessel components thickness, weight and costs unnecessary.
cheers,
gr2vessels