Fireclass 601F Conventional Solar Blind Infra Red Flame Detector for indoor use and boast a high degree of false alarm immunity. The standard unit is the 601F and it is designed for connection to a conventional zone of point type fire detectors that may include any mix of detection technologies. The 601FEx is an intrinsically safe version intended for use in hazardous atmospheres and must be connected via a suitable isolator or shunt diode safety barrier in a certified Intrinsically Safe system.