How to determine PSV protected against

[knapee]

Dear

PSV located on hot oil line discharge from the heater.(Please see attached)

I would like to known that PSV protected heater or thermal expansion on pipe line.

(PS. the heater is located above the flare height 7.6m so there is no fire case for this)

But, I wonder that this oil can't be evaporated so how to determine the relief load for this case on thermal expansion?)

Thank you very much.

 

[MikeClay]

See API Std 521 section 5.14 for details.

--Mike--