U-1 Vs Name Plate
U-1 Vs Name Plate
(OP)
I'm in the process of rerating a PV and just found that materials listed in U-1 forms are different from materials listed in nameplate.
PV was built back in 1972.
Which one should I use?
Thanks,
PV was built back in 1972.
Which one should I use?
Thanks,





RE: U-1 Vs Name Plate
Regards,
Mike
RE: U-1 Vs Name Plate
Do you mean materials listed on nameplate?
RE: U-1 Vs Name Plate
Get a PMI there and use that as your baseline. If it's a material grade issue, you're stuck getting coupons and testing. I certainly wouldn't trust either nameplate or U-1 in that situation.
RE: U-1 Vs Name Plate
Problem is that it's a material grade issue and I just can't cut a hole on the PV to get coupons and testing.
Thanks,
RE: U-1 Vs Name Plate
If any engineering or fab drawings are available, see if the material is listed on them. Hopefully it'll match one of the other two sources. I'm ok with going with two out of three.
I presume that the sucess of this rerate depends on the material grade? If not, take the weaker one and run with it. How 'bout running the calc's with the weaker one and seeing if the design is sufficient for the original design conditions. If it is, chances are the vessel was fabricated of the weaker material. If it is not, then its not unreasonable to presume that the higher grade is the correct one.
Finally, you can cut a hole in the vessel on the run if you need to get coupons for testing. If the tmin on the vessel is less than 3/8", I think you just might happen to need a new 3" nozzle somewhere on the vessel! Hot tap a new nozzle in as a repair since reinforcement calc's are not necessary, and keep the coupon for testing. Its not done frequently, but more often than you might think!
jt
RE: U-1 Vs Name Plate
Regards,
Mike
RE: U-1 Vs Name Plate
Vessel is 4.75" thick!!!!!!! with corrosion allowance of 1/16".
I'll go with materials listed on U-1 forms.
Thanks everyone for your comments and advise.
Corgas.
RE: U-1 Vs Name Plate