Hastings Electrician Smoke Alarms

Which smoke alarm do you need?

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Which smoke alarm do you need?

Smoke alarms give you an early warning of a real fire giving you time to evacuate. But what should you consider when buying a detector?

Ionisation smoke alarms

Ionisation alarms create a small charge inside a chamber to ionise the air between two electrodes.When smoke particles enter the chamber they cause an imbalance in the current and this initiates a signal to sound the alarm. Ionisation smoke alarms react to smaller smoke particles associated with smoke caused by flames than optical alarms, due to this sensitive trait it makes them unsuitable for areas close to kitchens but more suitable for dusty environments such as lofts, steamy areas outside bathrooms or near smoking areas.  

Optical or Photoelectric smoke alarms

Optical alarms use an infra-red LED beam of light which pulsates every few seconds into a sensor chamber to check for smoke. Unlike the ionisation smoke alarms, optical alarms detect the larger smoke particles produced by slow-burning, smouldering fires. If smoke enters the sensor chamber the beam of light is scattered onto the photodiode light receptor, triggering an alarm. They can be used near kitchens as they are less likely to cause a false alarm and are also suitable for bedrooms, landings, and hallways. However, they are not suitable for dusty areas, like lofts, or outside bathrooms.

Heat Alarms

As the name suggests heat alarms detect heat as opposed to smoke. The alarm will activate when the temperature inside the sensor chamber reaches 58 degrees Celcius. This would be an established fire and therefore unlikely to trigger false alarms. They can be placed in garages and kitchens as they do not react to cooking or exhaust fumes but in general are slower to react than either the ionisation or optical alarms. 

Battery or Main Powered?

Battery alarms are cheaper and you can fit them yourself, however, you will need to make sure you test them twice a year as a minimum and replace the batteries once a year. Mains powered alarms do need to be installed by an electrician but give you the peace of mind that they cannot easily be disabled. If you have them wired directly to your lighting circuit you can rest easy knowing if the lights are on the detectors are working.