relief valve

exchanger tube rupture
if the design pressure of lower pressure side is less than 10/13 of the design pressure of the higher pressure side ，provide over-pressure prection.
electrical power failure
cooling system that are dependent on electrical power, so the aircooler and
cycling water exchanger all deemed fail.
thermal relief
pipe containing flammable liquid，which have a risk of being left isolated during operation，which shall be provided with a single thermal relief valve