Fire-Lite D365PL Intelligent Non-Relay Photoelectric Duct Smoke Detector The Fire-Lite D365PL intelligent non-relay photoelectric duct smoke detector and DNRW watertight non-relay photoelectric duct smoke detector feature a pivoting housing that fits both square and rectangular footprints capable of mounting to a round or rectangular duct. These units sense smoke in the most challenging conditions, operating in airflow speeds of 100 to 4,000 feet per minute (0.5 – 20.32 m/s), temperatures of -4°F – 158°F (-20°C –70°C), and a humidity range of 0 – 93 percent (non-condensing).