Danger detector with a non-contact heat radiation sensor for detecting an open fire as well as to determine an ambient temperature

The invention relates to a danger detector, in particular a flame detector, comprising an alarm housing (2) with an alarm cover (21). Said housing part (22) of the alarm cover is permeable to heat radiation (W) in the central infrared range. A non-contact, optical heat radiation sensor (4a) which is sensitive to the incoming heat radiation and is optically oriented to the housing part is arranged in the alarm housing. A processing unit (4b) for further processing a sensor signal (SIG) emitted by the heat radiation sensor is mounted downstream of the heat radiation sensor. Said processing unit is designed to monitor the signal emitted by the sensor with respect to significant fluctuations or flicker frequencies for open flames and to determine, based on a direct component of the signal emitted by the sensor, a temperature value (TEMP) for the ambient temperature (T) in the surroundings of the danger detector. The heat radiation sensor is preferably a thermopile or a bolometer.