MDMT Criteria for Pressure Vessel

[Iyer S]

For the LP..
Fuel Gas Drum, MDMT (design)is -2 Deg C (27 Deg F)…..with Shell / Head Materials in SA516-60N + S5 + HIC..with Shell thickness (20 mm Top …24 mm Middle…20 mm Bottom and 24 mm thick Heads)

As we understand, SA 516 -60 material can sustain temperature upto (-29 Deg C)

Would like to know, the following
1. Whether the lower design temperature of vessel can be considered as (-29 Deg C )?...if not , why?
2. What is the minimum temperature (with the existing construction), the vessel can be subjected to?

 

[SJones]

A516 can "sustain" lower temperatures dependent upon thickness. It's not unusual to demand Charpy test temperatures lower than -29 deg C for the stated plate thicknesses. What test temperature has been specified for the S5 testing?

1. No. Because it has been set at -2 deg C as stated, and that's what will be stamped. Are you inquiring as to whether the MDMT can be changed to -29 deg C? If so, why would this be necessary?

2. The minimum allowable temperature can be determined using ASME VIII, Div 1, UCS-A-3, or API 579-1/ASME FFS-1, Part 3.

https://www.eng-tips.com/search.cfm?q=MDMT++516&action=search

Steve Jones
Corrosion Management Consultant

http://www.linkedin.com/pub/8/83b/b04

All answers are personal opinions only and are in no way connected with any employer.

 

[Iyer S]

Jones...that's a brilliant reply...thanks a lot..