Atmospheric pressure vessel in PVElite
Atmospheric pressure vessel in PVElite
(OP)
Hello, my coleague and i have a dis agrement about how to design a atmospheric pressure vessel in PVElite ( I know that PVElite is not intended for this kind of job but the firm we are working for has no other software)
- my view is that we should introduce something like 0.01 barg as an internal pressure ( PVElite gives an error if there is no internal pressure)( my logic is that API 650 does not take into consideration pressure but height of liquid )
- his view is that we should put 1 barg as internal pressure ( his logic is that because it's atmospheric , we should put 1 atm ( pressure exerted by the weight of air in the atmosphere of Earth ) = 1barg.
Which one of us is right ? And if there is a more correct way of calculating an atmospheric pressure vessel in PVElite pls do tell us.
Also another question : I am under the impression that PVElite understands by internal pressure , gauge pressure.
Am i right ?
Thank you all for response.
- my view is that we should introduce something like 0.01 barg as an internal pressure ( PVElite gives an error if there is no internal pressure)( my logic is that API 650 does not take into consideration pressure but height of liquid )
- his view is that we should put 1 barg as internal pressure ( his logic is that because it's atmospheric , we should put 1 atm ( pressure exerted by the weight of air in the atmosphere of Earth ) = 1barg.
Which one of us is right ? And if there is a more correct way of calculating an atmospheric pressure vessel in PVElite pls do tell us.
Also another question : I am under the impression that PVElite understands by internal pressure , gauge pressure.
Am i right ?
Thank you all for response.





RE: Atmospheric pressure vessel in PVElite
But you mention API 650. If your vessel contains liquid, I believe PVE will account for static head, which could serve as your design pressure.
Regards,
Mike
The problem with sloppy work is that the supply FAR EXCEEDS the demand
RE: Atmospheric pressure vessel in PVElite
My interest was in the pressure that is put as internal pressure.
I gave the example with API 650 because it deals with atmospheric storage tanks and that is why it doesn;t acount for internal pressure.
Thank you for your response SnTMan.
RE: Atmospheric pressure vessel in PVElite
Regards,
Mike
The problem with sloppy work is that the supply FAR EXCEEDS the demand
RE: Atmospheric pressure vessel in PVElite
As for API 650, I suspect we are saying the same thing in different ways but just to be clear: API 650 absolutely does include the hydrostatic pressure due to the liquid which is contained, but does not account for substantial vapor pressure above the liquid (which is where the design pressure / MAWP of a vessel is measured). That would be the reason why lower shell courses are frequently thicker than upper shell courses. And that's without getting into the bending situation at the bottom shell to bottom plate / ring.
RE: Atmospheric pressure vessel in PVElite
Also, if you put 0.1 in as your pressure and you add a liquid level, the software should develop a pressure for each shell section and the bottom head that includes the static head at the various levels...i know compress does this, not sure about PVE
The procedure for calculation of API thickness tells you that the calculation already includes 2.5psi of vapor pressure API 650 5.2.1(c). Also, you need to consider appendix f for roof design if you have pressure.
Sorry for the units and scratch the "may be law" thing! with the SI units, you are probably not in the US!
RE: Atmospheric pressure vessel in PVElite
API-650 does include allowances for up to 2.5 psi pressure in the vapor space- see Appendix F.
API-620 is similar but includes provisions for pressure up to 15 psi. It can also be used for suspended bottoms, but doesn't really give any guidance on the design or attachment of leg supports. It tends to be overly conservative in the design of the knuckle portions of F&D heads.
Meanwhile, I don't think ASME contains any provisions for a soil-supported flat bottom.
If no particular design code is specified, I would use the one most appropriate for the tank configuration.