Interlinked smoke alarms notify residents of a building if a fire breaks out in a distant room, where there could be a risk of not hearing the smoke alarm. Here is an example: a fire starts in the kitchen at night while the occupants of the house are asleep in bed. The alarm in the kitchen detects the fire and starts beeping, this message is relayed to the interconnecting alarms throughout the building to alert all occupants and will also rouse them from their sleep, allowing for a safe escape from the fire. An interlinked system for such a scenario will consist of at least one heat alarm in the kitchen and a smoke alarm in the bedroom or on the landing.
There are different ways of interlinking smoke alarms, most of them involve cabling between each unit. Wireless smoke alarms, however, do not require a cable between each alarm; they pass the signal between the different detectors as a radio frequency signal. This way of passing a signal is accepted by British Standards as an alternative to wiring between alarms.
Wireless smoke alarms,have broadly speaking, four power supply options:
- Battery operated (alkaline)
- 10 year battery operated (usually involves an arrangement of sealed-in lithium batteries)
- Mains powered with alkaline backup batteries (batteries need changing regularly)
The mains powered alarms, while using RF (radio frequency) signals for the communication between themselves, have, of course, some wiring for the power supply. Each of these smoke alarms is supplied with power from either the nearest light fitting or a separate mains power supply circuit.
Mains powered wireless smoke alarms fully satisfy the standard BS5839-6:2013 Grade D, however the sealed ten year power supply of the Ei600TYCRF wireless fire alarm series is usually also accepted as Grade D alternative by Building Inspectors and fire safety officers. Please ask your Building Inspector or fire safety officer before installing the ten year Ei600TYCRF series if your building requires Grade D alarms.
Each of the above smoke alarm series include a range of different fire detection sensors, usually:
- Ionisation smoke alarms – Detect the electrical property changes of the air in case of a fire
- Optical (photoelectric) smoke alarms – ‘See’ smoke when it enters its detection chamber
- Heat alarms – Detect the increase in temperature from a fire
Depending from the application and the room, a specific sensor type is necessary. This can be quite confusing if you are not an expert.
To aid in this selection process Safelincs has developed a website dedicated to explaining wireless smoke alarms. We have also created a system selector tool to help you pick the correct units for your building. Just select the power supply type, enter the number and type of rooms to be protected and the system will place the correct smoke alarms into your basket.
If you still have questions, please contact our friendly customer service on 0800 612 6537 and we are happy to help you.