Design Pressure & Temp Vs Op pressure & temp

[Captainobvious]

Got a tricky one that I can`t find clear justification in the Code (ASME V111 div 1)

Designing a pressure vessle, need to use 600# flanges, this can not change.

Got a design pressure of 1480 PSIG. therefore max temp is 100F. I am told we gan set the operating temp to 100. However my pople want to set non coincedental limits at 1425 PSIG and 150 F.

The outside max temp is 120F.

My question is 1) what makd a non coincedental factor according to the code (UG24), and if the max outside amnient temp is 120F will I be able to get away with a design temp of 100F.

basically I want to lower the Design Pressure (usuall operating is 435!!) but I need to justify this to my team.

Any experts in the code would be gratefull

 

[prex]

Unclear to me what ambient temperature has to do with your problem: if the vessel temperature is determined by the ambient, you should derive from this a through wall average metal temperature, this will form the basis for determining the design temperature.
If your vessel is in thermal equilibrium with the surrounding space at 120F, can't see how the design temperature was defined as being 100F.
Also unclear is your reference to UG-24. The code allows you to define more than one set of design pressure-temperature values, so you could have the vessel stamped for that. However each pressure-temperature couple should correspond to a defined process state or transient condition.

prex

http://www.xcalcs.com

: Online tools for structural design

http://www.megamag.it

: Magnetic brakes for fun rides

http://www.levitans.com

: Air bearing pads