Development of Improved Strategies for the Lay-Out of Fire and Gas Detectors

Fire and Gas (F&G) detection is an essential part of the mitigation system in facilities handling and storing flammable and toxic materials. While detector reliability might be very high, safety performance of a F&G system strongly depends on layout and coverage. Current reference standards for on-shore applications do not define the plant areas to be mapped, the coverage targets, and the reference hazardous scenarios to be considered. In the present study, a methodology aimed at the F&G coverage mapping was developed. The procedure is applicable in the Front End Engineering Design phase (FEED), where limited data is typically available. The development of the methodology considered the main aspects that define F&G system performance. Coverage targets for detection were set considering risk reduction goals and actual detector capabilities. Simple strategies were developed for the determination of the reference hazardous scenarios to be considered. A Matlab code for 3D F&G coverage mapping was developed. The proposed procedure was demonstrated by a simplified case study. The methodology proved itself a valid instrument to assist detector layout assessment.