In case of a fire in oil and gas plant which level of shutdown to be take place,which device sensing the fire or flame in a plant?

The ESD emergency shuntdown   will be level 0, Global shundown with general  depressurization time maximum 15 minutes, and to start up all equipements fire water pumps and discharges all fire extinguishing systems in facilites : powder & foam, CO2 and FM200, , of course the ESD system depends on which zone (0,1,2) in crude oil facilites ,  wet gas facilites ............it depends on studies HAZOP and HAZID in EPCCS and operation phases fire detectors: ultraviolet and  heat-sensitive cable