Why do Pressure Vessels require a greater material thickness than Piping?
Why do Pressure Vessels require a greater material thickness than Piping?
(OP)
When I look at the minimum thickness calculation in ASME VIII, I notice the calculation requires a greater metal thickness than say B31.3. Even if you account for the same material this is still the case.
This a common issue with chemical plants when they design a small vessel using the Piping code only to learn later that if it was designed to the Pressure vessel standards the minimum required thickness would be greater.
What is the reason for this? Is this because pressure vessels have a greater stored energy compared to piping hence the need for a thicker material?
This a common issue with chemical plants when they design a small vessel using the Piping code only to learn later that if it was designed to the Pressure vessel standards the minimum required thickness would be greater.
What is the reason for this? Is this because pressure vessels have a greater stored energy compared to piping hence the need for a thicker material?
RE: Why do Pressure Vessels require a greater material thickness than Piping?
RE: Why do Pressure Vessels require a greater material thickness than Piping?
It could easily be that "most" PV's are relatively large with lots of openings, dished ends etc, whereas pipe under pressure is rarely > 48" and in most plants is more likely in 1" to 24".
The two codes don't work well at their extremes.
"This a common issue with chemical plants when they design a small vessel using the Piping code " Is it?? There have been many debates here on whether you can just make something out of pipe to say B31.3 or other code as opposed to ASME VIII and the usual answer is no. PV definition is a legal and safety issue so I don't recognise your phrase as being correct IME.
It annoys me when pig traps on pipelines get designed as a Pressure vessel, because that really is an extension of the pipeline and is universally recognised as such in the pipeline design codes, but for a process plant??
Remember - More details = better answers
Also: If you get a response it's polite to respond to it.
RE: Why do Pressure Vessels require a greater material thickness than Piping?
I know that's not what the code says though.
I agree with you
@LittleInch
RE: Why do Pressure Vessels require a greater material thickness than Piping?
2) The different allowable stresses between PV and piping are not the cause, they are a consequence.
3) PVs have more complex detail fabrications, so higher risks and more inspections and NDEs are required.
4) Most PVs have longitudinally welded shells, some with two of them.
5) Most PVs are made in the shop. Lifting, transport and erection are other risks.
The above mentioned (and others) are the cause of greater thickness than the piping.
Regards
RE: Why do Pressure Vessels require a greater material thickness than Piping?
And so forth
Huub
- You never get what you expect, you only get what you inspect.
RE: Why do Pressure Vessels require a greater material thickness than Piping?
why is a pressure vessel with a diameter less than 6" exempt from the code?
I wish these codes contain more background information on have reached their requirements.
RE: Why do Pressure Vessels require a greater material thickness than Piping?
Huub
- You never get what you expect, you only get what you inspect.
RE: Why do Pressure Vessels require a greater material thickness than Piping?
RE: Why do Pressure Vessels require a greater material thickness than Piping?
Huub
- You never get what you expect, you only get what you inspect.
RE: Why do Pressure Vessels require a greater material thickness than Piping?
RE: Why do Pressure Vessels require a greater material thickness than Piping?