What types of Smoke Alarms are there?
There are two types of smoke alarm – Ionisation and Optical (also described as Photoelectric). Ionization smoke alarms are very sensitive to small smoke particles, produced by flaming, fast fires such as from a chip pan. They are marginally less sensitive to slow burning and smouldering fires, which give off larger quantities of smoke before flaming occurs. Optical smoke alarms are more effective at detecting larger smoke particles produced by slow-burning fires such as smouldering foam-filled upholstery and overheated PVC wiring. They are marginally less sensitive to flaming fires. Each type looks similar and is powered by a battery or mains electricity or by a combination of both. Some have additional features such as an escape light (can light-up the escape route) and a silencer button (for use where false alarms can be a nuisance e.g. when cooking). Some are interconnectable so that smoke detected by one smoke alarm will cause all the other units to alarm.
