subject: Optical Smoke Alarms Vs Ionisation Smoke Alarms [print this page] Optical Smoke Alarms Vs Ionisation Smoke Alarms
The safety of your home or workplace is of paramount importance. Smoke alarms were invented to warn you if a firebreaks out,but which do you choose - optical smoke alarms or ionisation smoke detectors? In this article we will explore the differences.
The Optical Smoke Alarm
This type of smoke alarm uses light technology to detect smoke. Inside of these alarms, there is a small light emitting diode or LED. This little light shines a thin beam of infrared light to a sensor. If any small particles of smoke interrupt this infrared light the voltage read by the sensor will drop and the alarm will sound. This type of smoke alarm is best where the threat of smoldering, thicker smoke is present.
The Ionisation Smoke Alarm
This type of smoke alarm employs a completely different technology to detect smoke particles in the air. This type of smoke detector has about one milligram of radioactive metal in it, that has been scientifically proven safe for humans. The sensor part of the smoke alarm is called an ionisation chamber. Inside of this chamber there are a small amount of electrodes with a current running through them.
If a small particle of smoke enters the chamber it ionises the radioactive element in the alarm and the current flowing between the electrodes is interrupted. This causes the alarm to start beeping. This type of detector is good at detecting smoke when the fire is more flaming than smoke producing because it can detect such small particles.
Which Is Better?
Ionisation smoke detectors can detect smoke much quicker than optical smoke alarms due to the difference in technology. However, the ion type of smoke detectors are extremely sensitive and can cause more false alarms than their optical counterparts.
Many manufacturers are starting to discontinue the production of ion smoke detectors because of the great advances in optical smoke detection technology. Those that continue to produce both ion and optical smoke alarms usually house them in the same outer casing.
The only real way to determine which type of detector you are buying is to read the packaging that comes with your smoke detector. Ionisation detectors are more sensitive and expensive, while optical smoke detectors are cheaper but less sensitive.
In order to get the best of both worlds you should employee both types of detector in your home, but remember to check them regularly and change them every 10 years.
