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Contaminated (dirty) Smoke Detectors

Dirty smoke detectors are one of the most common causes of nuisance (false) alarms. With regular inspection, testing and maintenance dirty smoke detectors can be easily identified and replaced, improving the reliability and safety of fire detection systems for building occupants.

Dirty Smoke Detector

By its very design a smoke detector is intended to detect the presence of contamination from airborne particles, typically smoke.

Unfortunately there are a great deal of other particles that when built up over time can adversely affect the performance of a smoke detector.

This adverse effect can be reflected in two ways;

  • the smoke detector becomes more sensitive, and may cause false alarms; or
  • the smoke detector becomes less sensitive and may not operate correctly in the event of the presence of smoke.

Most modern addressable fire detection and alarm systems have the capacity to record the level of contamination of a smoke detector over time. When an individual detector exceeds a predetermined threshold it can signal a warning (not an alarm) that it is becoming contaminated and needs attention.

Every fire detection & alarm system operates differently however this principle is typical for most systems.

Common causes of contamination

The most common type of contamination is caused by atmospheric particulates being circulated by the heating and air-conditioning systems in buildings. Other causes include building works including, carpentry, sanding, painting, and the like.

If you have ever left a level surface in a building for more than a week, you will see these particulates accumulate, and smoke detectors are no exception.

Early indication there may be a problem

While many fire detection & alarm systems can identify a contaminated smoke detector not all of them provide a readily visible or audible warning. In addition, there is currently (2012) no Standard requiring contaminated smoke detectors be reported.

The most common early indication that there may be a problem is two or more nuisance alarms from the same detector or area within a building.

What you can do about contaminated smoke detectors

All fire detectors have a finite operational life, and this varies for every type, make, model and installation conditions.

In addition, technology changes and some fire detectors become obsolete or difficult to replace cost effectively.

When a contaminated smoke detector has been identified, there are generally two options available;

  • replace the existing smoke detector with a new unit; or
  • replace the existing smoke detector with a compatible refurbished (cleaned) unit.

Firewize can offer customers both options depending on the specific site specific requirements.

For more information about smoke detectors, please refer to our series of articles on the Principles of Fire Safety as follows;

Request a FREE QUOTE for an addressable smoke detector contamination report. Complete your details (below) and we will contact you to arrange a time to discuss your requirements.