And if I do not know what MDMT is?
As chemical process engineers, you need to understand some definition to keep our process in a safe condition.
MDMT is an acronym to Metal Design Minimum Temperature and mean the lowest permissible metal temperature for a given material at a specified thickness based on its resistance to brittle fracture.
As important as MAWP, MDMT is stamped in the nameplate of all ASME vessels. But must be known to piping system material also.
In cryogenic design for air separation units (ASU), for instance, and process operating below 32F (0C) condition we are familiar with MDMT, however, special attention to the depressurization system. Even though they normally not operate at low temperatures, a depressurization can lead to a temporary high-temperature decrease and reach material MDMT if not well designed. Understanding fluid thermodynamics will predict this kind of situation and will help you select the right material for your process.
Brittle fracture can lead to system rupture and loss of content.
