ASME VIII Design Temp for boot 1

[pipesvessels1]

All,

I have a Flare Knock Out Drum with DT of 150oC but I have some steam coils coming into the boot of the vessel at 245oC. The temp of the fluid in the boot is not allowed to exceed 90oC before shut-off however the nozzle attached to the steam coil could theoretically reach 245oC.
What is the DT of the vessel?
Does ASME VIII have any mechanism for defining different DT's for a single vessel?

Regards,

 

[jte]

pipesvessels-

Yes, it is not uncommon for ASME vessels to have different design conditions in different areas. Refinery fractionation columns often have different design temps at the top and bottom.

For a code reference and assuming you're working to Div. 1 (you didn't state whether you're working Div. 1, Div. 2, or Div. 3) see VIII Div. 1 UG-20. In particular, note in (a) that it states "...for the part considered" not "for the entire vessel." Then see (d) which makes it very explicit that multiple desing temperatures are ok.

jt