Minimum Design Metal Temperature MDMT
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For pressure vessels designed in accordance with ASME standards, how should the minimum design metal temperature (MDMT) be determined? Should it be based on the extreme lowest temperature in the location of construction, or on the average temperature during the coldest month of winter? Where in the ASME standards is it mentioned?
The minimum design metal temperature, MDMT, is determined based on the lowest value of the average monthly minimum temperatures over the years in the location where the construction takes place; this data can be obtained from the statistical records of the local meteorological service.
It is calculated; the calculation method is provided in ASME Section 8-1.
In general ASME equipment design, the MDMT of the vessel is a value specified by the customer; when designing the vessel, the designer calculates (or determines) the MDMT of each component and compares it with that of the vessel. If it is higher than the vessel’s MDMT, an impact test must be conducted. Impact-free test for MDMT below the container limit. See the example in the attachment
View the charts from ASME VIII-1 UCS-66