A smoke detector is a vital component of any home. Early fire detection can be the difference between death and survival.
The Fire Protection Association (FPA) Australia recommends that every home have smoke detectors in all living and sleeping areas. These detectors should remain interconnected to ensure everyone in your home gets alerted in case of a fire.
Learn more about the types of smoke detectors below, how they work, and their pros and cons to ensure you choose the best one for your home.
What a Smoke Detector Does
Most home fire fatalities occur when people are sleeping at night. Installing smoke detectors gives you and your loved ones the best chance to stay safe in case of a fire. Regardless of the size of your home, smoke detectors will notify you if there are any fire signs, allowing you to respond swiftly.
The Two Types of Smoke Detectors
Smoke detectors sense smoke particles in the air through two primary detection technologies: Photoelectric and ionisation. Ionisation-based detectors can sense tiny black soot particles that flaming fires produce. Photoelectric sensors are more sensitive to larger, light-coloured particles from smouldering fires because they are more reflective.
Both detectors can identify flaming or fast-burning and smouldering or slow-burning fires. However, each technology has pros and cons, as discussed below.
How a Photoelectric Smoke Detector Works
Photoelectric smoke detectors have a sensing chamber with an invisible infrared light beam. They function by sensing light reflected by particles in the light beam. If there are no particles in the sensing chamber, the beam’s light will not reach the light detector, so the alarm remains silent.
However, if there’s a fire, the smoke particles interfere with the amount of light that reaches the detector. If they exceed a certain threshold, the alarm will trigger and produce a high-pitched sound.
Pros
- Photoelectric smoke detectors react faster to smouldering fires that are yet to develop big flames
- They have no radioactive materials
- There a less likelihood of false alarms due to bathroom or cooking steam
Cons
- They require regular maintenance because they are sensitive to insects and dust particles.
- Less sensitivity to smoke can be dangerous in fires with big flames
How an Ionisation Smoke Detector Works
Ionisation smoke detectors have an ionisation chamber with shielded radioactive material such as americium. The radioactive material electrically ionises or charges air molecules between two electrodes. This generates a small electric current running through the air from one electrode to the other.
If particles are in the chamber, the ions attach to them, reducing the flowing current. The device senses and triggers the alarm when particles increase and reduce current to a particular threshold.
Pros
- Ionisation smoke detectors are suitable for traditional homes with regular cooking activity and shower steam
- They react better to fast flaming fires
- They detect fires caused by small combustion particles like a lightning strike
Cons
- Ionisation smoke detectors are prone to more false alarms, so most people intentionally disable them to avoid nuisance
- They react slower to smouldering fires
- The radioactive materials can be unsafe
- They work best in rooms with combustible materials like newspapers, flammable liquids and cleaning products.
Conclusion
Various fires can start in any room in the house. Regardless of how or where they start, installing a smoke detector is an excellent step toward ensuring your loved ones’ safety.
Ideally, it’s best to have both detector types because their strengths complement each other. If you’re unsure which type is best for your home, call an electrician to find out what smoke detector is best for you.
