Finned Tube MDMT Criteria 1

[caper656]

Hey everyone. I have an old 80's heat exchanger I am reviewing and it was ASME nameplated for -60F MDMT. This is alittle colder than I have dealt with so I am seeking advice. The box's plate/nozzle pipe/flanges have been impact tested per UG-84 to -60F MDMT but I am curious about the Ring/Groove finned tube mechanical connection and the finned tube's material selection of SA-214. Typically, we would update the tube material to something more known for low temp application. Either way, I haven't found anything in ASME that considers MDMT of the tubes or the ring/groove connection to the tubesheet. What is everyone's thoughts?

 

[SnTMan]

You won't find anything on the connection to the tubesheet, as MDMT is generally applied to materials, rather than fabrication details. Disregard it.

The tubes are presumably thin enough that they can be exempted totally, or if not, perhaps the assigned MDMT can be reduced based on low stress.

See UCS-66(d), UCS-66(b).

Regards,

Mike

The problem with sloppy work is that the supply FAR EXCEEDS the demand