Catch the Drift

March 2016

Part two of our series of articles on fire panel migration.

Smoke detectors act as the fire panel’s scout team charged with performing tasks critical to overall reliability and performance. Regardless of how long smoke detectors have been installed, we expect them to display the information we need during a fire condition as if the detectors were “right out of the box.”  Unfortunately, this is not the case with legacy conventional fire panels, as they are susceptible to sensor drift. Irrespective of the installation date, new intelligent fire panels and their devices maintain sensitivity as if they were installed yesterday.

What is sensor drift?

Sensor drift is a general term used to describe when an electronic device is no longer sensitive in the range to which it was originally manufactured. Virtually all sensor devices are susceptible to drift, especially older, conventional smoke detectors.  As smoke detectors drift with age, they become more sensitive to their environment.  So, is this sensitivity a good thing?  Generally, no.  A smoke detector that has drifted is now vulnerable to false alarms and false discharges, both of which can become a nuisance or a costly business interruption.

Can you prevent drift?

No. General environmental contaminants, such as dust, collect on critical electronic elements over time which will cause the smoke detector to drift from its original manufactured sensitivity. Minuscule changes in relative humidity of the installed environment can also cause the smoke detector to drift. Unfortunately, even if the environment is 100% controlled and there are zero airborne dust particles, the smoke detector will continue to drift over time simply due to electronic aging.  Electronic aging is a real phenomenon that all electronic devices experience over time.  Think about using a computer every day for eight years.  It is likely that the old desk ornament is not quite as powerful as it was on day one.

Drift Compensation

Intelligent fire panels and their intelligent smoke detectors win the battle against smoke detector drift by a feature that is called drift compensation. Drift compensation is a sophisticated proprietary algorithm that smooths the sensitivity and returns the device’s relative alarm threshold to its original installation condition.  When an intelligent detector and fire panel are installed at a facility, the smoke detector learns the environment for 30 days from which it creates its installed baseline.  The smoke detector will then continue to operate at a consistent threshold above the baseline for the life of the installation.  This field learning translates into fewer false alarms and business interruptions from smoke detector drift.

Older is not wiser when it comes to conventional smoke detectors and they can become costly reminders of how aged the fire protection system might be. Updated intelligent control panels and their devices offer reliable detection and protection for many years after installation.


Stop the drift. Learn more here.

Contributor: Adam Tracy is a Senior Sales Engineer and holds a BS in Civil Engineering, an MS in Fire Protection Engineering, and an MBA. Adam maintains expertise in all aspects of fire suppression including system design, hazard analysis, fire testing and code development.

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