Mains Radio-Interlinked Optical Smoke Alarm with Alkaline Back-up - BRK 660RF

BS 5839-6 recommends that one or two storey HMOs with an individual floor area of no more than 200sqm (not the total of both floors) should have a Grade D smoke alarm system installed. Grade D refers to mains powered smoke alarms with a back up battery power supply. The alarms can be interlinked either by wire or by radio signal and the system does not require a separate fire alarm panel. For HMOs of 3 storey or higher, a Grade A panel system would need to be installed. This can cover the whole of the building, or can be used just for the communal areas with a separate Grade D system installed for the individual dwellings. For both applications, the level of cover should be a minimum of LD3 (in all escape routes) but this may change according to the fire risk assessment.

Yes, should the radio interlinking signal fail the units will continue to sound independently should they detect a fire.

In modern housing the lighting circuit will travel around your house with the lights being fed from it. Between the circuit and the light will be a switch (or in this case a dimmer) which will control the light. Your mains powered alarms are connected directly to the circuit and have constant power, so are not affected by switches or dimmers. In older homes that have not had the electrics updated this may not be the case so it is advisable to consult an electrician.