Rehydrotesting of a shop certified ASME SEC. VIII Div.2 vessel in the field

[qualitypro]

I would like to know if a ASME VIII Div.2 vessel shop hydrotested at about 5000 psig and approved by the AI outside the US can be subjected to a rehydrotest in the field as part of the associated piping system circuit. The field piping joints are directly buttwelded onto the vessel nozzles and the customer is not inclined to have flanged joints or golden welds as we are dealing with high pressure critical toxic systems. Are there specific code requirements to be followed and are Code cases available that support this case? If so, what are the precautions to be taken per design code.

 

[GD2]

OP,
What is the piping code? Usually, the piping Code will give you guidance on how to hydrotest a piping system with vessel with it.
If your vessel is vertical, make sure that the hydrotest pressure can be different than what was in the shop test, that is generally done with the vessel in horizontal position on the ground.
Obviously, you need to follow the allowable stress limit for test condition per 4.1.6.2 of the Division.

GDD
Canada