Smoke DetectorsSmoke Detectors or Smoke Alarms sense the presence of smoke in the home and alert the occupants, giving time to escape.
There are two types of smoke detectors or alarms:
- Photoelectric smoke alarms - contain a light source whose beam is deflected by smoke onto a photocell, causing an alarm to sound.
- Ionisation smoke alarms - use a minute amount of radiatiactive material to detect the presence of smoke, thereby causing an alarm to sound. Radiation authorities advise that the amount of radiation emitted from these devises is much less than natural background levels.
Smoke alarms can be either wired into the household electricity mains (with battery backup), or be battery operated only. Wired-in alarms are considered more effective in the longer term.