All Flame detectors are vulnerable to activating alarms due to nonfire sources and the confusion of fire sources with nonfire ones. In this article, I will recommend reducing false alarms in flame detectors.
Why False alarms reduction is important
False alarms are more than a nuisance—they are a productivity and cost issue. Therefore, flame detectors must discriminate between actual flames and radiation from sunlight, lightning, arc welding, hot objects, and other non-flame sources.
How to reduce flame detector false alarms
Lower sensitivity
When you set a flame detector to higher sensitivity, you run a higher risk or vulnerability of alarming nonfire and friendly fire sources.
Reducing the sensitivity will reduce the possibility of false alarms. Most flame detectors come with deep switches that can help you set the sensitivity to high, medium, or low. I recommend selecting medium sensitivity.
Reduce Field Of View (FOV)
Focus the detector’s FoV on the primary threat area and avoid false and nuisance sources outside it.
In some cases, a field-of-view restrictor accessory may be necessary to focus the Flame Detector on the area to be protected.
Use a voting system
When more than one flame detector is installed in the area, the voting system is recommended.
The voting system is simple logic that will be performed through a controller. No alarm will be activated unless two or more detectors activate fire alarms.
The best approach is to vote for two detectors that cover the same threat area from opposing perspectives so that a single detector covering the threat area that alarms a source outside or beyond the threat area will not initiate suppression by itself.
Set a Fire Verification Time (affects the Auxiliary Relay)
Some flame detectors like FS20X and FS24X Plus have a user-selectable verification time that can be set via a DIP switch setting on the back of the detector module.
Setting a verification time of five, ten, or twenty seconds means that the secondary alarm (Auxiliary Relay) will not activate unless the fire continues to burn during the entire verification time.
That’s it. These are tips on how to reduce flame detector false alarms. Thank you for reading.
