Requirements for fire and gas detection corresponds to hazards present within a facility. The Fire and Gas Detection Mapping study in turn, is performed to verify adequacy and effectiveness of coverage provided by these fire and gas detectors. FGDM studies at PRISM are performed using a mapping software, based on a 3D structure to provide visualization on location and coverage of detectors within a geometry PRISM have capabilities to perform both Geographic Coverage assessment and Scenario Coverage assessments in accordance to industry codes, standards and guidelines Geographic coverage assessments provide visualization on location and achieved detection coverage within a specified geometry Whereas the Scenario Coverage assessment is a Risk Based approach to assess achieved detection adequacy and effectiveness.