Fireye 55UV5 self-checking scanners are used to detect ultraviolet emissions from fossil-fuel flames, such as natural gas, coke-oven gas, propane, methane, butane, kerosene, light petroleum distillates, and diesel fuels, and are suitable for use in Class I, Div. 2, Groups A, B, C, D and Class II, Div. 2 Groups F and G hazardous locations.