Minimum design metal temperature.
Source: API 510, Pressure Vessel Inspection Code: In-service Inspection, Rating, Repair, and Alteration, Tenth Edition, May 2014, with Addendum May 2017. Global Standards
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