MDMT
MDMT
(OP)
On occasion, the MDMT is specified by the end user as an arbitrary
value.The vessel fabricator is then responsible to
verify that the actual MDMT of every component used in
that pressure vessel is lower than the arbitrary value
requested for the nameplate stamping. Why lower?
value.The vessel fabricator is then responsible to
verify that the actual MDMT of every component used in
that pressure vessel is lower than the arbitrary value
requested for the nameplate stamping. Why lower?





RE: MDMT
Second, at or below MDMT.
RE: MDMT
When you perform calculations for MDMT, rated MDMT can be equal or colder than required MDMT.
Regards.
RE: MDMT
ASME even utilizes this concept in VIII-1 Figure UCS-66.2.
RE: MDMT
For example, if you have a low-pressure CS vessel designed to ASME VIII-1 using Compress, it will often tell you the rated MDMT can be as low as -55°F. This however only takes into consideration the base metal, and ignores the impact on welding. With CS, you hit a breakpoint at -20°F when impact tested weld procedures and production impact tests become required. This can add additional cost to a vessel, and is why you often see CS vessels rated to -20°F.
RE: MDMT
RE: MDMT