10 Mar What could be causing a false alarm?
False Alarms can be due to the wrong type of Flame Detector being used. As a rough rule of thumb, IR2 and IR3 Flame Detectors should not be used outside unless protected from direct sunlight, which can False Alarm Flame Detectors. To get an activation, all the sensors in the Flame Detector must be in Fire and then there must be a ‘flicker’ or modulation of that signal.
Inside False Alarms: If a Flame Detector False alarms inside and the sun has not been shining directly onto it (if it is an IR2, IR3 or Spark Detector), the following has always been present:
Extreme Heat: a very hot process which gives of a heat of over 300 – 400 degrees can give off all the Infra-Red (and Ultra-Violet) needed to trigger a Flame Detector. The heat can also cause a haze to appear over the process, which combined with the IR will appear as a fire to a Flame Detector.
High Ambient Temperature: If the ambient temperature of the risk area gets above the maximum rated temperature (+55 degrees for the Standard and +85 degrees for the Enhanced version), the sensors are much more sensitive to an IR and can False Alarm.
Strong Infra-Red source: Flashing lights on a dump truck at a recycling centre False Alarmed an IR2 Flame Detector.
Outside False Alarms:
Sunlight: IR2 and IR3 Flame Detectors can be False Alarmed by direct or reflected sunlight shinning directly onto the front of the Flame Detector. Water can reflect sunlight, so puddles can cause problems to IR2 and IR3 Flame Detectors even if they are hidden from the sun. Use UV/IR2 Flame Detectors outside.
Reflections of steels: Outside metalwork has been known to False Alarm Flame Detectors by ‘bouncing’ IR through to the Flame Detector. Welding arcs can be picked up by Flame Detectors from the IR/UV signals being reflected by steel work.