Why are there ionisation and photoelectric smoke alarms?

Question

What is the difference between ionisation and photoelectric smoke alarms (detectors)? Which one is best for me and that I should purchase?

Answer

The photoelectric type is the superior choice between ionisation and photoelectric smoke alarms. Why? We explain…

Photoelectric sensing technology

Photoelectric smoke alarms are generally more sensitive to larger particles which tend to be produced in greater amounts by smouldering fires, which may smoulder for hours before bursting into flames. Once again, smoke alarms are meant to give you extra time to evacuate from a fire, or take action against one if safe to do so.

Key advantages of photoelectric smoke alarms:

  • No radioactive components are used.
  • Early detection of smouldering fires.
  • Reduced ‘false alarms’ such as from cooking and burning the toast in the morning.

Ionisation sensing technology

Ionisation smoke alarms are identified by a radioactive symbol on the unit
Ionisation smoke alarms are identified by a radioactive symbol on the unit
Ionisation smoke alarms are generally more sensitive to small particles which tend to be produced in greater amount by flaming fires, which consume combustible materials rapidly and spread quickly.

Smouldering fires, which photoelectric smoke alarms are better at detecting, can smoulder for quite some time before bursting into flames. In that time you could have potentially taken action against the smouldering fire and put it out, or at least safely evacuated and called the fire brigade.

Which type is more effective?

    All fire services throughout Australasia support photoelectric smoke alarms
    All fire services throughout Australasia support photoelectric smoke alarms

  • Ionisation smoke alarms meet sensitivity and performance requirements, however many experts believe they provide insufficient protection in typical residential fires.
  • All Australian state fire authorities now recommend photoelectric smoke alarms.
  • Ionisation smoke alarms are more likely to cause false alarms, which is the prime reason for occupants removing their batteries to disable them and forget to put them back in again – an extremely dangerous decision!
  • In the Northern Territory, ionization smoke alarms are required to be replaced with a hard-wired 240V photoelectric smoke alarm with 9V back-up battery or a photoelectric smoke alarm with a sealed 10-year lithium battery when their existing alarm ceases to work, the property is sold, the property is rented or a tenancy is renewed, or a caravan or moveable dwelling is hired-out. Similar changes are coming to Queensland from 2017 that will require photoelectric smoke alarms, along with interconnected smoke alarms to be installed in all bedrooms.
  • The most significant problem identified among regions with smoke alarm legislation is a lack of enforcement and compliance monitoring.

Family First specialise in photoelectric smoke alarms.