A testing device for fire detectors comprises a resistance heating coil disposed outwardly of a clear central area and a collar located to one side of and about the resistance heating element for locating of a fire detector relative to the heating element. The heating element is of a low thermal mass...http://www.google.ca/patents/US5170148?utm_source=gb-gplus-sharePatent US5170148 - Radiant energy testing device for fire detectors
