ASME FIRE REQUIREMENTS FOR PSV
ASME FIRE REQUIREMENTS FOR PSV
(OP)
ASME VIII states that a 21% overpressure should be used for fire or other unexpected sources of heat. I usually see "fire" interpreted as meaning a pool-fire.
Does anyone have any examples of "unexpected external sources of heat?" Any example specific to refineries that you have designed for in the past?
thanks.
Jonathan
Does anyone have any examples of "unexpected external sources of heat?" Any example specific to refineries that you have designed for in the past?
thanks.
Jonathan





RE: ASME FIRE REQUIREMENTS FOR PSV
(a) Perhaps you can consider radiation heating from a fire that is normally outside the API fire zone, or from the atmospher.
(b)Perhaps you have a jacketed vessel normally on cooling fluid but has a cross-over for whatever reason to a steam line. Steam gets into the jacket, that sounds like an unexpected external (to the vessel) heat source to me.
(c) A possible failure in the wall of a fired heater nearby an exposed vessel (maybe streatching this one a bit).
I'd be interested to see what others may come up with.
RE: ASME FIRE REQUIREMENTS FOR PSV
I am glad to hear this question has made other people wonder as well. The only source of external heat that i have ever seen a relief load calculated for is for pool fires. Jet fires are not generally protected against with PSV (per API 521).
Jonathan