Smoke detection in Private Dwelling

[Ryanmac1984]

Hi All,

A bit of advice is required if possible. My friend has a fairly new home in which there are 2 mains powered smoke detectors. They have recently built an extension to the side and a sun room at the rear. The drawing shows 2 additional smoke detectors to be installed, one in the sun room, and one in the hallway of the new extension leading to the new rear door.

The smoke detectors have not been installed as per the drawings, so they have asked my advice on how to do this but i am not 100% on the latest regs for private dwellings, (i install fire & security systems) i believe they need a category D system which means mains powered smoke detectors, however as they already have 2 detectors hardwired, can they get away with installing 2 battery powered smoke detector which are interlinked wirelessly so if one detector triggers the other also alarms as i read that these types of detectors can substitute hard wired category D detectors.

Any help would be greatly received.

 

[RF Lighting]

I'd suspect no. The new alarms will need to be linked to the existing ones, but ask the buildings inspector as it him who requires them, and will make you do the job how he wants it done, which will most likely be as per the drawings upon which planning permission was granted.

 

[PrenticeBoyofDerry]

The requirements are a little different in Scotland. I would go with the recommendation set out by building controls.
It is relatively easy to install mains/battery back-up, that are interlinked using a hybrid system of linked hardwired and RF bases.

 

[Ryanmac1984]

Thanks,

i am not sure of the regs and i believe my friend has left it last minute, the inspector is coming out at the beginning of the coming week. Im sure the regs will be different in Scotland, but i always find the regs to be inconclusive. Too many variations as opposed to an exact can or cannot do.

You mention a hybrid system, i have never seen/heard of these, do you have an example or a brand so i can look into them?

 

[deadshort]

If you install two battery alarms which are audible from the furthest part of the house ,BC will not have any issues with the installation.

Regards,

DS

 

[skenk]

Scottish building regs Domestic Handbook 2013

at least a Grade D fire detection and fire alarms system should be installed in every dwelling
...
smoke alarms and heat alarms should be mains operated and permanently wired to a circuit which should take the form of either:
• an independent circuit at the main distribution board, in which case no other electrical equipment should be connected to this circuit (other than a dedicated monitoring device installed to indicate failure of the mains supply to the alarms) or
• a separately electrically protected regularly used local lighting circuit.
.....
The standby supply for smoke alarms and heat alarms may take the form of a primary battery, a secondary battery or a capacitor.
....
Interconnection - all smoke alarms and heat alarms in a dwelling should be interconnected so that detection of a fire in any alarm, operates the alarm signal in all of them. Smoke alarms and heat alarms should be interconnected in accordance with BS 5839: Part 6: 2004.

The proposed alarm in the new hallway will be needed to comply with a grade D system. The sun room possibly not but if it's shown on the drawings it should be done regardless, and some properties require a higher grade than D anyway.

Do let us know what happens!

 

[flyingsparks]

If you install two battery alarms which are audible from the furthest part of the house ,BC will not have any issues with the installation.

Regards,

DS

Not sure about that. They must be interlinked.

 

[SimonH2]

It's a bodge, but IIRC Aico can have a mix of wired and wireless interlinking.

Is it too late to run the cable needed (typically you need a 3C&E) from one of the exiting detectors ? If it is, who was responsible for following the plans, IMO your friend should be "negotiating" with that person on the basis of "the plans said X, you were responsible for following the plans, how do you propose to deal with X ?"