SnTMan, sorry for the later reply (email had the alert email in junk folder).
Thanks for looking at the thickness range tolerances per SA-20.
Yes, some corrosion has certainly occurred, at least in pit areas. These vessels we inspect often have tons of dissolved oxygen and can be out-of-whack...
Thanks David for the reply!
Ok good catch, the shell had a average measured thickness of 0.308" (ranged 0.283" - 0.312"), 5/16" is more likely.
Ok, am I reading you right, that the actual material nominal thickness used during construction should/must be listed on the U-1A?
If so the two...
Our NDT Technicians measured via UT the thickness of an in-service vessel shell wall to be around 0.350" thick.
The U-1A lists the Nominal Thickness as 0.250".
I calculated the min required wall thickness per ASME BPVC Section VIII para UG-27 to be 0.158". [ri=17.75", P=150 psi, S=20ksi...
