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How do I know if my smoke alarm needs replacing and where do I install them?

Friday, April 06, 2018

Two types of smoke alarms are commonly found in Australian homes; Photoelectric and Ionisation. It is important to note that currently both types can be legally purchased and used, as both meet the required Australian Standard AS3786. However, for a number of years now, photoelectric smoke alarms have been the only type recommended by Australian Fire Authorities and Fire Brigades, as well as the International Association of Fire Fighters. In fact, a global campaign is now calling for a total ban of ionisation alarms.

For that last 2 years we have been using Photoelectric Smoke Alarms for New homes, replacement or adding to existing homes.

Highly recommend replacing smoke alarms older the 8 years as this is the life span of smoke Alarm.

Batteries replaced once a year and tested.

Hard wired smoke alarms should have a green light and can be easily swapped over to a Photoelectric if older than a few years for your peace of mind.

Smoke alarms shall be interlinked and positioned in every out room, passage from bedrooms, so all smoke alarms are triggered and operate together.

But what’s the difference and why are photoelectric detectors so highly recommended? For the most part, it’s all about how they detect fires and importantly, how quickly they respond.

Photoelectric Smoke Alarms

These alarms detect visible particles of combustion so it is often said that they ‘see’ smoke. They work by aiming a light source into a sensing chamber so that when smoke particles enter the chamber, light is reflected onto the sensor, triggering the alarm.

The fact is that in both the real world and controlled instance of smoke alarm testing, they have been proven to be more effective and respond significantly faster to smouldering fires. These are fires which are slower burning and produce a lot of smoke, the most common type in the home environment. The faster you can be alerted, the more precious time you have to get yourself and your family to safety. They are also less likely to emit false alarms from cooking or steam in the bathroom.

Ionisation Smoke Alarms

These alarms are said to ‘smell’ the smoke that comes from flames, in that they detect invisible particles of combustion. As opposed to photoelectric alarms, these work through a small amount of radioactive material that exists between two electrically charged plates. This material ionises the air, causing a current between the plates. When smoke enters the chamber, the flow is disrupted, activating the alarm.

While they are not generally recommended over photoelectric detectors, they do activate more quickly for fast flaming fires. The disadvantages however are significant. They are slower to respond to smouldering fires, which can lead to visibility and breathing difficulties when occupants are attempting to escape a house fire. They are also prone to more false alarms, resulting in people removing the battery and thereby losing all protection.

Contact us

If you have any questions in relation to smoke alarms, home fire safety or the change-over offer, please don’t hesitate to contact us.


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