Smoke alarms work by detecting small particles of smoke. They can do this because they contain tiny sensors, and they are very sensitive. The particles that are being detected only have to disturb the light inside the sensor chamber of the alarm in order to set the alarm off.
Because smoke alarms need to allow in smoke particles, they are prone to other matter entering the alarm and affecting or even damaging the smoke sensor.
Possible contamination that reduces the effectiveness of a smoke alarm might include:
- Lizards or insects nesting or exploring inside the alarm can disrupt the sensor. They also create a build-up of dirt and waste inside the alarm.
- Dust in general builds up inside smoke alarms blocking the path of air to the sensor chamber.
- Cooking and cigarette smoke create a build-up of tar or grime on both the internal and external surfaces of the smoke alarm which effects the alarm sensitivity and makes it easier for dust to stick to the alarm.
Also smoke alarms have a shelf life and like any manufactured device can just degrade over time. Sometimes the lifespan of a smoke alarm can reduce if the alarm is handled more than usual by the occupants of the home.
Cleaning smoke alarms:
- Firstly, disconnect smoke alarm from its main power source.
- Remove as much of the dirt, dust and insect residue as possible from inside the alarm. This can be done by holding the end of a vacuum cleaner up to the open areas of the alarm. Depending on the design of the alarm this may prove to be un-effective. If that is the case it may be possible to blow dirt out of the alarm, however this should be done carefully with short, soft, dry bursts of air.
- Large bits of dirt that get stuck may be swiped out of the alarm opening using a cotton bud.
- Once all loose dirt has been removed use a cleaning wipe to wipe all the external surfaces and remove any surface dirt or grime.
Testing and resetting the alarm.
Note: All smoke alarms should have a battery of some form regardless of whether they are mains powered or not.
- Hold the test button down for 3 seconds and ensure the alarm goes off at a high decibel reading of at least 75dcb. Ideally the decibel reading will be more than this because it diminishes by the time the sound travels to the various bedrooms. Experts suggest there should be a 75dcb reading at the bed head.
- Smoke alarms should be tested and cleaned every 6 to 12 months although for rental properties legislation requires this to occur within 30 days prior to the renewal of or start of a lease.
- If an alarm can be reset, it is worthwhile doing this. Look for the user manual for your alarm model online and then find the instructions for resetting the alarm.