Minimum design metal temperature (MDMT)
The lowest temperature at which a significant load can be applied to a pressure vessel as defined in the applicable construction code (e.g. ASME Code, Section VIII: Division I, Paragraph UG-20(b)).
Source: API 510, Pressure Vessel Inspection Code: In-Service Inspection, Rating, Repair, and Alteration Downstream Segment, Ninth Edition, June 2006. Global Standards
Minimum design metal temperature
Lowest metal temperature likely to be reached in operation, normally taken as the lowest fluid temperature to which the riser will be exposed in service.
Source: API RP 17G, Recommended Practice for Completion/Workover Risers, Second Edition, July 2006 (Reaffirmed April 2011). Global Standards