When it comes time to upgrade or replace the smoke detectors in your property, there are a variety of smoke alarms available to keep you and your family safe from fire and smoke. The two most common types of smoke detectors are ionization and photoelectric. In this article, we will discuss the benefits of photoelectric detectors and answer the question, “are interconnected photoelectric smoke alarms safe?”.
What Is the Difference Between Ionisation and Photoelectric Smoke Alarms?
Inside each ionization smoke detector is a small amount of radioactive material that converts air into a current that flows between two electrically charged plates. When smoke enters ionization fire alarms, it disrupts the ions — reducing the flow of the current and subsequently activating the alarm. Look at the rear of your smoke alarm. If it has the black and yellow trefoil radiation symbol on it, that means it is an ionization smoke alarm.
Conversely, inside each photoelectric alarm is a beam of light that is aimed at a specific angle away from a sensor. When smoke enters the internal light-sensing chamber, it reflects the light onto the sensor — thus triggering the alarm.
The Safety Benefits of Photoelectric Fire Alarms
1. Photoelectric Smoke Alarms Are More Sensitive to Slow Smouldering Fires
The main benefit of photoelectric fire detectors has to do with early detection. Most house fires typically smolder for a period of time before actually bursting into flames and spreading. Photoelectric fire alarms are more sensitive to the larger smoke particles produced by smoldering fires — they tend to trigger in the earlier stages of a fire. This will give you and your family a greater response time to deal with an emerging fire threat or to safely evacuate the building before the smoldering turns into a full-on flame fire. Numerous scientific studies have demonstrated that photoelectric smoke detectors are more adept than ionization detectors at detecting smoldering fires, typical of most house fires.
2. No radioactive components
Although there is a minuscule amount of radioactive material present in each ionization alarm, and it is not considered dangerous, even to touch, many people prefer to have no radioactive components in the home at all. For this reason, photoelectric fire alarms are a favorable choice. Ionization smoke alarms are gradually being phased out of the Australian marketplace, being replaced by photoelectric.
3. Fewer false alarms from kitchen and shower steam
Unlike photoelectric alarms, the trigger mechanism in ionization fire alarms is more sensitive to all types of gas particles — including steam from cooking and the shower. Ionization smoke alarms, therefore, are more prone to cause false alarms. For this reason, many people were inclined to remove the smoke alarm batteries to prevent nuisance alarming — this, of course, deactivated the alarm and left households exposed to potential fires (also a cause of many fire fatalities). Photoelectric fire alarms are less likely to cause false alarms from steam.
4. Interconnected photoelectric smoke alarms
Modern photoelectric smoke alarms have the ability to be interconnected together wirelessly, so if one alarm in the property detects smoke, then all alarms will activate. Doing so can provide a greater early warning and response time for occupants of a dwelling (therefore increasing safety). Many states of Australia, including Queensland, have begun legislating for the mandatory installation of wireless photoelectric interconnected smoke detectors in properties being leased or sold. In QLD, for example, this requirement will also become mandatory for all homes by 2027.
Where Do I Install Interconnected Smoke Detectors?
To increase safety and effectiveness (and reduce nuisance alarms), smoke alarms must be positioned correctly in the home. To maximize smoke alarm operation, avoid installing smoke detectors in the following positions:
- In ‘dead air space.’ Dead air space represents an area or air pocket in which trapped hot air will prevent smoke from reaching the alarm. This space generally occurs at the apex of cathedral ceilings, the corner junction of walls and ceilings, and/or between exposed floor joists.
- Near windows, doors, ceiling fans, or air conditioners. Excessive air movement may prevent smoke and gases from reaching the smoke alarm or cause nuisance alarms.
- In or outside of the bathroom, steam can trigger nuisance alarms due to water vapor simulating high humidity.
- In insect-infested areas, insects flying into the alarm could cause nuisance alarms.
Smoke alarms must not be placed:
- within 30cm of a corner of a ceiling and a wall;
- within 30cm of a light fitting;
- within 40cm of an air-conditioning vent;
- within 40cm of the blades of a ceiling fan.
There are also special requirements for stairways, sloping ceilings, and ceilings with exposed beams – for these requirements, it is always best to refer to state legislation and the local fire department for guidance.
Conclusion
Ionization smoke alarms use a small amount of radioactive material to sense smoke, whereas photoelectric smoke alarms use a light beam to ‘see’ the smoke. Photoelectric smoke alarms are more adept at detecting slow, smoldering fires, which are typical of most common house fires – for this reason, interconnected photoelectric smoke detectors are the preferred type of smoke alarm in Australia today.
Be sure to install interconnected photoelectric smoke alarms in all prescribed locations as per state legislation. In the Australian state of Queensland, this means inside every bedroom, the hallway outside the bedrooms. If there is no hallway, then the nearest exit path from the dwelling and a minimum of one detector must also be installed on every level of the dwelling. It is recommended to avoid problem areas such as kitchens, bathrooms, garages, and insect-infected areas to reduce the possibility of false/nuisance alarming. No one wants to be woken up at 2 in the morning due to a false alarm!
Install Interconnected Photoelectric Smoke Alarms Today!
When it comes to providing maximum protection against fire hazards for your family, home, and loved ones, there should be no compromise on safety – for this reason, interconnected photoelectric smoke alarms are definitely the preferred choice.