Smoke detectors are an important safety feature in your home. They are proven to save lives and get assistance to limit damage to your property and neighbours.
It’s really important that every smoke detector in your home is well-maintained. Over time smoke detectors can be influenced by dust, kitchen grime, humidity, insects and age, so they need to be checked frequently, have the batteries changed yearly and the whole unit replaced at least every ten years.
It’s worthwhile thinking about changing your smoke detectors even more often than this. New technologies are entering the market all the time, constantly improving the quality and ability of these little life-savers. As well as getting a quality upgrade when you change to a new smoke detector, you have the opportunity to think about their placement and get the perfect setup for your home.
What a smoke detector does
A smoke detector is an early warning device designed to detect smoke in the area around it and notify residents with a sharp alarm.
There are two benefits here: Firstly, fire damage can usually be limited and contained if extinguished quickly. Secondly, many home fires occur at night. This is a dangerous situation as people sleeping cannot smell smoke and can succumb to suffocation before a fire takes hold.
Waking people at night with an alarm gives them a chance to get out of a property quickly and call for help.
The two types of smoke detectors
There are two main types of smoke detection technology: photoelectric and ionisation. A smoke alarm can use either one or both of these combined. Some also include a heat detector.
How a photoelectric smoke detector works
The inside of the photoelectric smoke detector holds a light and a sensor. These are carefully positioned at 90-degree angles to one another. When the atmosphere is normal, light inside the chamber misses the sensor, continuing in a single, unbroken line.
In the case where smoke enters the chamber, the particles in the air fragment the light and cause the beam to scatter, hitting the sensor, at least in small amounts. As soon as this happens the alarm is sounded. If the light and sensor were in line with each other, it would take a huge volume of smoke to block the beam and get off a warning. This setup makes these detectors so effective as an early warning to a smouldering fire.
How an ionisation smoke detector works
Ionisation works within an internal chamber where charged oxygen and nitrogen atoms are attracted to one of two distanced plates. The movement of this attraction between the plates generates an electric current that will continue unless disturbed. Any amount of smoke in the chamber will attach to the displaced ions, cutting off the flow and reducing the current. This is the trigger for the alarm.
Pros & cons
While both types of smoke detectors are good at detecting smoke and issuing an early warning, they do behave in different ways. Photoelectric detectors are best suited to smoky fires, such as a smouldering mattress, while ionisation smoke detectors are better suited to high-fuelled fires that burn with fast intensity.
There is no way to know in advance what type of fire you might encounter but it’s important to know that both fire types are equally dangerous. For help and advice call an electrician to find out what smoke detector is best for you.
To play it safe you can double your cover. Many Australian regulation-approved smoke detectors offer both systems in one device, or, you can place each detector side by side to offer protection no matter the circumstances. This will give you the best early warning system to save property and lives.