Tugboat1984
Specifier/Regulator
- Jan 24, 2015
- 7
I have a pressure vessel that has a U-1 form (as well as the nameplate) that has two different sets of MAWPs and MDMTs.
One MAWP is 250 psi @ -20F to 300F and the other MAWP is 85 psi @ -20F to -50F.
This vessel is operated on a 24/7 basis between -30F and -40F.
The vessel contains anhydrous ammonia and is operated at around 9"hg.
Questions:
Which MAWP do I set my RV's to? 250 psi or 85 psi or something else?
Can I operate the vessel at the conditions of -40F (with an MAWP assigned of 85 psi) with 250 psi RV?
If yes, where in ASME UG-125 does it permit this design?
I understand that manufacturers can provide additional MAWP and MDMTs, but how does an owner/operator comply? I have upload the U-1 form.
One MAWP is 250 psi @ -20F to 300F and the other MAWP is 85 psi @ -20F to -50F.
This vessel is operated on a 24/7 basis between -30F and -40F.
The vessel contains anhydrous ammonia and is operated at around 9"hg.
Questions:
Which MAWP do I set my RV's to? 250 psi or 85 psi or something else?
Can I operate the vessel at the conditions of -40F (with an MAWP assigned of 85 psi) with 250 psi RV?
If yes, where in ASME UG-125 does it permit this design?
I understand that manufacturers can provide additional MAWP and MDMTs, but how does an owner/operator comply? I have upload the U-1 form.
