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Hi folks,

Friend is currently renovating his house, including a loft conversion. He had originally hoped to go with Grade F1 (tamper proof batteries) radio interlinked alarms. However architect has stipulated all alarms must be Grade D (mains powered with battery back-up), but can be still be radio interlinked.

All walls and celling's are up, plastered and painted. So looking to minimise damage where possible when installing.

It's going to be pain to run a separate circuit from CU for alarms and to have them hardwired interlinked, but if needs to be done that way then so be it. Same would also apply if running separate mains alarm feed cable connecting into lighting circuit MCB at CU.

So was wondering what your views would be on doing the following (not ideal in my mind, but a possible workaround).

  • Downstairs alarms mains feed of downstairs lighting circuit (can 'easily' access - minimal damage).
  • Upstairs alarms mains feed of upstairs lighting circuit (can 'easily' access - minimal damage).
  • All alarms radio interlinked (could hardwire interlink downstairs, hardwire interlink upstairs with radio interlink between upstairs and downstairs).

Look forward to your input.
 
TL;DR
Smoke/fire alarms powered of two separated circuits?
  • Thread Starter Thread Starter
  • #3
Is your friends house in England or Scotland? If Scotland which council?
Located in Scotland, Argyll & Bute.

Have tried to argue the case that Scottish government website, indicates that F1 grade would be fine, but architect said no, must be Grade D. :(
 

Julie.

Arms
Esteemed
No rules stipulating that they have to be on the same circuit.

Also the Scottish government standard allows for radio Interconnected systems.

Just check that the alarms, type, location, and quantity complies with the tolerable standard as issued by the Scottish government.

Btw there is no regulation in the Scottish standard that prohibits the use of fixed battery alarms Interconnected via radio.

Did the architect misunderstand what was being suggested?
 

James

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Mentor
Arms
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Esteemed
The only risk that I see you might have to be careful to avoid the possibility of shared or borrowed neutral .

Hard wire interlinking is often done with a live feed from one to the other, if they are on separate circuits then some current will pass down wrong neutrual.
 
  • Thread Starter Thread Starter
  • #6
No rules stipulating that they have to be on the same circuit.

Also the Scottish government standard allows for radio Interconnected systems.

Just check that the alarms, type, location, and quantity complies with the tolerable standard as issued by the Scottish government.

Btw there is no regulation in the Scottish standard that prohibits the use of fixed battery alarms Interconnected via radio.

Did the architect misunderstand what was being suggested?
Thanks for input. Separate circuits will save a lot of work. :)

All I know is that my friend has been back and forward with the architect over this, and architect is refusing to budge on this, so to keep the peace will be going with Grade D alarms as stipulated by the architect, hence OP.
Post automatically merged:

The only risk that I see you might have to be careful to avoid the possibility of shared or borrowed neutral .

Hard wire interlinking is often done with a live feed from one to the other, if they are on separate circuits then some current will pass down wrong neutrual.
Interlink between downstairs and upstairs circuits would be radio not hardwired, so no risk of borrowed neutrals. Thanks.
 

richy3333

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Mentor
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D2, LD2 which means mains powered as per BS5839-6. As suggested you could radio link them.

Btw there is no regulation in the Scottish standard that prohibits the use of fixed battery alarms Interconnected via radio.
But BS5839-6 Table 1 does prohibit this?
 
  • Thread Starter Thread Starter
  • #8
D2, LD2 which means mains powered as per BS5839-6. As suggested you could radio link them.


But BS5839-6 Table 1 does prohibit this?
Would appear BS and Scottish government are not 100% in sync.

Guess Scottish government position is that having smoke alarm(s) whether it's mains or battery powered is better than not having any at all.

On a separate note, if I bought every BS standard that I would touch upon, then storage of these alone (forest of paper) would results in an increased fire risk ;)
 

Julie.

Arms
Esteemed
D2, LD2 which means mains powered as per BS5839-6. As suggested you could radio link them.


But BS5839-6 Table 1 does prohibit this?
Not on existing properties - F2 would be acceptable - but NOT in Scotland, here F1 is the minimum, it depends on how upgraded the property is, but if it's a loft conversion then the loft portion may be regarded as materially altered so D2 there.
 
  • Thread Starter Thread Starter
  • #10
Not on existing properties - F2 would be acceptable - but NOT in Scotland, here F1 is the minimum, it depends on how upgraded the property is, but if it's a loft conversion then the loft portion may be regarded as materially altered so D2 there.
Ahhh...that may explain why architect stipulated grade D. Thanks.
 

Julie.

Arms
Esteemed
Would appear BS and Scottish government are not 100% in sync.

Guess Scottish government position is that having smoke alarm(s) whether it's mains or battery powered is better than not having any at all.

On a separate note, if I bought every BS standard that I would touch upon, then storage of these alone (forest of paper) would results in an increased fire risk ;)

They are not in Sync, but the Scottish rules go beyond the UK.

F2 is not permitted for any mandatory detectors - but can be used for additional.
The minimum quantities under BS5839 are not sufficient under Scottish law.


The law in Scotland is that EVERY home MUST have interlinked alarms:
Main living room
Each circulation space on every story
Kitchen (Heat)
CO in every room with fossil fuel device (boiler/fire etc) or containing a flue.
ALL sensors must be ceiling mounted

Not just new builds/modifications - however F1 is considered acceptable.

BTW, alarms from different circuits cannot be interconnected, only via wireless in these cases.

You could interconnect say all the alarms on each story and just have one wireless on each circuit connecting to the other circuit.

Wouldn't be ideal but has been accepted in Scotland.


The law is here:



A Typical older house would require
3 x smoke,
1 x heat
plus:
CO in the Boiler location
CO in the front room (Gas fire)
CO in the Living room (Gas fire)
CO in the front bedroom (The flue from the downstairs gas fire passes through)
CO in the Rear bedroom (The flue from the downstairs gas fire passes through)

All either mains powered, battery back up interconnected, or 10 year battery with wireless

Scottish government expect this is £200
 
Last edited:
  • Thread Starter Thread Starter
  • #12
They are not in Sync, but the Scottish rules go beyond the UK.

F2 is not permitted for any mandatory detectors - but can be used for additional.
The minimum quantities under BS5839 are not sufficient under Scottish law.


The law in Scotland is that EVERY home MUST have interlinked alarms:
Main living room
Each circulation space on every story
Kitchen (Heat)
CO in every room with fossil fuel device (boiler/fire etc) or containing a flue.
ALL sensors must be ceiling mounted

Not just new builds/modifications - however F1 is considered acceptable.

BTW, alarms from different circuits cannot be interconnected, only via wireless in these cases.

You could interconnect say all the alarms on each story and just have one wireless on each circuit connecting to the other circuit.

Wouldn't be ideal but has been accepted in Scotland.
Whoops wasn't aware that F2 could only be used for additional non-mandatory detectors. Thanks for all of your help. :)

I'll be seeing my friend (social distanced of course) later on the evening, to work out best plan of action. Well keep you updated on final solution that satisfies both BS5839 and Scottish government requirements.

Thanks to everyone for your input. :thumbsup:
 

littlespark

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Arms
Esteemed
I think architects have basic plans written up concerning smokes, accessory heights and even make of accessories... (“MK or equivelant”.... why?)
Sounds like they haven’t updated their scripts to include 10yr battery or radio options

I’ve just looked at a plan for knocking 2 flats into one, and the architect has asked for a carbon DIOXIDE Co2 detector monitor for the master bedroom.
Assume it’s to act as a sounder for the co detector at the boiler.... which is written on the plan as MONOXIDE
 
  • Thread Starter Thread Starter
  • #14
I think architects have basic plans written up concerning smokes, accessory heights and even make of accessories... (“MK or equivelant”.... why?)
Sounds like they haven’t updated their scripts to include 10yr battery or radio options

I’ve just looked at a plan for knocking 2 flats into one, and the architect has asked for a carbon DIOXIDE Co2 detector monitor for the master bedroom.
Assume it’s to act as a sounder for the co detector at the boiler.... which is written on the plan as MONOXIDE
Maybe they plan to install a soda stream in the master bedroom - they are making a come back. Nothing worse than when you come to use it and is ran out of CO2, because it's been leaking - hence need for detector ;)

Maybe also trying to reduce carbon foot print by going for a MONOXIDE detector....:rolleyes:
 
New build in Scotland should have a carbon dioxide alarm in the master bedroom, I fitted one a couple of years ago. It is because modern property is so sealed up they say there is a risk from carbon dioxide build up!! The house I did had a Carbon dioxide 2 carbon monoxide, a heat detector and two smokies all interlinked.
 
  • Thread Starter Thread Starter
  • #16
New build in Scotland should have a carbon dioxide alarm in the master bedroom, I fitted one a couple of years ago. It is because modern property is so sealed up they say there is a risk from carbon dioxide build up!! The house I did had a Carbon dioxide 2 carbon monoxide, a heat detector and two smokies all interlinked.
That's a new one to me. Thanks for sharing. Better take back my tongue and cheek soda stream comment....:pensive:
 

Lister1987

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Trainee
Supporter
What I can't get my head around is that BS5839-1 not being sufficient. Surely rather than the devolved approach we appear to have, WHY on matters like this (fire safety, electrical safety etc) does the British government doesn't put the boot down and prohibit devolved 'modifications' to long standing, well...standards.

I'm not against them wanting change but I'm fully against devolved decisions, I mean just look at the COVID debacle we have at the moment....
 
Building standards in Scotland and NI have always been different from England, nothing to do with devolution.
 

Lister1987

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Trainee
Supporter
Building standards in Scotland and NI have always been different from England, nothing to do with devolution.
Begs the question as to why it was allowed in the first place and not universally applied across the UK? Same with laws, why must everywhere outside of England have laws that apply just to them? Surely if it's a good law with reasoning for it then it would make sense to apply it across the board? I'm getting the thread off topic so I'll can it 😂
 
Cant speak for NI but about 300 years ago England tried to standardise legal systems etc but due to mass rioting in Scottish city's Scotland was able to retain its Church, legal system, education system etc.
 
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