Smoke alarms on extension

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New member
May 31, 2022
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HI all,

Basically have a detached house with a Nest smoke alarm in, and a Flat 10mtrs away.

they are being joined together with a 1 story extension

just wondering,

Do i need smokes in the house ( hall, landing)
then smoke in the extension(main room with log burner) and in the flat (hall landing) all interlinked

all will be nest batteries so they will linked wirelessly.

he said the drawing only shows one in the house and one in the extension lounge area.

I've told him I'm pretty sure it's the above I've set out (drawings a bit crap

Any advise would be appreciated)

In all newbuilds/refits in England/wales must have a smoke alarm on each level, also one in the main habitable area (usually the lounge) as well as a heat detector in the kitchen, a CO detector in any room that has a fuel burning appliance.

It should also be considered what level of detection is being installed (shortened version)

All D grade detectors must be mains powered.
D1 Detector has lifetime battery
D2 Detector has user replaceable battery

All F grade detectors are battery powered
F1 Detector has lifetime battery
F2 Detector has user replaceable battery

Little known fact: Nest detectors have an inbuilt feature that when the device is 10 years old, it will switch itself off, that is 10 years from date of manufacture, not first powered. It will let you know at 3 months, one month and again at 7 days prior.

Although smoke alarms should be replaced at 10 years, others will continue to work (although not at their best) past the 10 year life expectancy.
From a quick search the Google Nest detectors are not compliant with BS5839-6 or Building Regs so it would need a rethink
It is not clear from the OP whether the property is a private residence or rental property which will affect the choice of detectors available