Min. thickness calculation for corroded vessel 2

[farzam]

Dear All,

we have a vessel in service that measured thicknesses of some different locations of vessel show reduction in thickness(corroded).Now we have to calculated Min. thickness that applicable for vessel,I have a question that for nozzle attachment performing WRC is mandatory?or only calculation of Min required thickness of shell and nozzle is enough.

Thanks in Advance

 

[metengr]

Yes, you need to determine if current nozzle reinforcement is adequate, based on code of construction rules.

 

[jte]

farzam-

You do not make it clear whether or not the design corrosion allowance has been exceeded. If not, then clearly a bit of corrosion is not an issue since the vessel should have been designed, including supplemental loadings such as a WRC-107 type analysis, with the corroded (retirement) thickness used for the calc's. So look at the new thickness and subtract the designed for CA from the vessel data sheet and you have your retirement thickness.

If your vessel has corroded beyond the nominal CA then you are in a fitness for service situation. Hire a person who is familiar with and competent in FFS evaluations. This is something you should not be attempting yourself if you have to ask whether all loadings need be considered for a FFS evaluation. If you do perform a FFS evaluation and the equipment fails, would you be comfortable explaining in person to the widow and children that their husband & father died because you didn't know what you were doing but were under management pressure to not expend the resources necessary to get competent help? Hope is not a strategy.

jt

 

[farzam]

Dear jte,

Thank you very much for your comment