ASME code U or UM?

[AngelM]

Hello guys,

Which is the difference between the ASME code U and code UM certification for pressure vessels?
Regarding a vessel manufacturer of reservoirs for mechanical seal, they both would offer the same guarantee? or it would depend on the consitions?

The difference is only the dimension or the max. pressure applicable?

Please, give me a light on this topic.

Thanks

 

[flexibox]

See if this helps you.

http://www.eng-tips.com/viewthread.cfm?qid=110122

And

http://www.sureflowequipment.com/What_is_ASME.cfm

Regards