Hello guys,

I have a water treatment unit with a skimmer tank operating slightly above atm. pressure.
As first it was considered to install a PSV for fire case set @ 3.5 barg (vessel design pressure).
However,a colleague came with some calculations saying that fire case was not a credible scenario due to the time to heat up the whole liquid inside the vessel (D=3.2 m et L=16.8 m. and wetted area of 135 m2).
Using API 521 heat flux formula, he shows that it takes several hours just to heat up the whole volume to the boiling point.
I don't get confortable with this and want to get some feedbacks from experienced guys.
Thanks.