Pressure vessel nozzle sch/thk
Pressure vessel nozzle sch/thk
(OP)
If the shell and head thickness increases, do we have to also increase the nozzle schedule/ thickess eventhough the desing pressure and design temperature is the same throughout?
The vendor agrue that the nozzle sch/ thk has to be increase because the hydrotest pressure increase from 8.9barg to 21.9 barg. of course initially the vendor take the MAWP as the design pressure but in the second rev , the vendor calculated the MAWP and the MAWP increases from 6.9barg design pressure to 16.8 barg .
1. So what I wanted to know is why is there a need to increase the nozzle sch /thk ? Is it really neccessary?
Can someone please explain to me?
Thanks alot . Cheers.
The vendor agrue that the nozzle sch/ thk has to be increase because the hydrotest pressure increase from 8.9barg to 21.9 barg. of course initially the vendor take the MAWP as the design pressure but in the second rev , the vendor calculated the MAWP and the MAWP increases from 6.9barg design pressure to 16.8 barg .
1. So what I wanted to know is why is there a need to increase the nozzle sch /thk ? Is it really neccessary?
Can someone please explain to me?
Thanks alot . Cheers.





RE: Pressure vessel nozzle sch/thk
RE: Pressure vessel nozzle sch/thk
RE: Pressure vessel nozzle sch/thk
The answer is probably yes, but you'd need to provide more details to check. I suggest you review UG-45 of VIII-1 (assuming ASME is the CoC).
RE: Pressure vessel nozzle sch/thk
Regards,
Mike
RE: Pressure vessel nozzle sch/thk
RE: Pressure vessel nozzle sch/thk
Cheers,
gr2vessels
RE: Pressure vessel nozzle sch/thk
Another possible cause (given the OP's reference to CA) would be a confusion between MAWP and MAP. For a relatively thin wall vessel, a 3mm CA could cause a substantial difference between MAWP and MAP. And if this vessel is designed to my company's spec's (or several others') then the hydrotest shall be MAP based (for VIII Div. 1 that would be UG-99(c)).
Lots of unknowns here. Darrenyee - can you provide some more detail, if only to close the loop with the forum?
RE: Pressure vessel nozzle sch/thk
What I understand is that initially MAWP was limited equal to design pressure and nozzle was designed for MAWP.
Now, you have calculated the MAWP and by default, software is calculating nozzle parameters for MAWP considering it as a design pressure. If you are using COMPRESS, this may be the case.
If I have not understood your query, please elaborate it.
RE: Pressure vessel nozzle sch/thk