I came to know the few difference between U & UM.

In getting the U stamp, the complete vessels has to be inspected by Authorised Inspector (start from Design Cals to Hydro Test, Final Insp and Manufaturig Data Report), whereas in getting UM stamp there is no need for Authorised Inspector, manufacturer's Certified Inspector can sign the MDR (U-3 instead of U-1 or U-1A)

But apart from that, there are some restrictions with reference to Pressure, Temperature and Volumetric Capacities of the vessels.

Can anybody provide me the information regarding that, and also, please inform me that, where can I look for the same in ASME Section VIII Div. 1

Mac,

U-1(j) is the starting point.

For the UM stamp, the company shall have a U Certificate at least, and the duties of the Authorized Inspector are handed over to the Certified Individual, who is employed by the Manufacturer.
The QCManual shall be audited annually by the AIA Supervisor, between the triannial ASME Joint Reviews.

All other Code requirements fully apply.

DK

DK,

Thanks