Very Interesting Ideas Here
Here is my personal experience with ASME Code Section VIII, DIV 1 vessels that have been in "fire" damage areas both offshore and onshore:
1) First if possible get a copy of the UIA, you may need it later.
2) Identify the material via the UIA or if not, logic assumptions can be made via the nameplate information, MFG Date, hydrotest pressure, RT-X and etc.
3) I use a vessel design program and plug the information to get the expected material thickness for the head and shell with an assume liguid level.
4) Do in-depth visual inspection of the discoloration areas. Look for the paint in particular, assuming CS, because different paints degrade at different temperatures. Example Inorganic Zinc, above 900 F starts to deterorate quickly. Point is, do we have a vessel that now went over 1100F for P1 material or not.
5) Hardness reading can be useful for P1, but materials like SA-516-70 you will find the hardness goes down. The reason is if at some temperature above 800F the heat for extended periods removes the cold work from rolling the plate and therefore reduces hardness, i.e. BHN.
6) Best advise given above, get a professional that has documented experience working with AI agency to review and make determinations. At the end of the day, re-hydro test and if necessary, request a R-1. I am sure you will find something to fix.
7) No fast assumptions here when you get into these. Best example is like calling a doctor on the phone and saying "I hurt, what is wrong with me?"; lol. To do this properly you must see the patient and know the service the vessel was in and what the fire media was made up of, like burning by-product in a paper mill can have some nasty stuff in it.
Only my opinion and certainly does not apply to all cases.
Regards,
Allen
Sindel & Associates