Discuss Smoke detector false alarms in the UK Electrical Forum area at ElectriciansForums.net

Dartlec

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Having a bit of a mare at the moment with a small 2 story HMO (6 single rooms with shared kitchen) which was fitted relatively recently (2016 or so I think) by someone else but I was asked to do an annual certificate for one of my regular landlords as she was being fleeced by a 'professional' company.

Last year was fine with no issues and only thing that came up at this year's inspection in January was a missing detector in one of the rooms. Also appeared someone from the management company had replaced some with incompatible models, but they did all work.

Since then there have been several false alarms leading to call outs late at night by the management company engineers, who did nothing but unplug them all and push it back to the landlord, claiming a 'loose connection' on one visit, and a 'faulty alarm' on another.

Since then I've replaced the incompatible ones, redone all the original dodgy terminations at each fitting, and yet apparently they were going for 2 hours last night.

It's a Grade D LD1 system, with detectors in each bedroom, up and down hallways, and heat in kitchen. There is no detector near the kitchen that could be picking up cooking fumes.

The units are all Firex, mostly KF20s with one KF20R and a KF30 heat alarm. The oldest ones are still fine until 2028, and they all had batteries in place.

I was able to test continuity from the start of the circuit to what I think is the end, though didn't do IR testing as some units were still in place. They all tested fine with test button and smoke can.

The claim is that the hush button isn't working when they do go off, but since there are no staff on site and the tenants are not the most reliable it's hard to get accurate information.

My suspicion is that at least one of the tenants is smoking a certain substance and/or buggering with the detector, but hard to prove that of course. It's not very local and access is difficult too as the housing management company has to be there to get access to the bedrooms.

Are false alarms that cause multiple hour long alarming sessions out of nowhere that common with these alarms? If so what are possible causes?

Any suggestions for other tests that could be done to identify or confirm that there is no fault in the system?

I've read through the latest 5839-6, and for existing HMOs, they actually only recommend LD2, so I'm toying with the idea of suggesting the room ones aren't interlinked with the others, but wary of reducing the existing protection without very good reason.

Although each room has fire doors, it's really only a small house, and the hallway smokes should be enough to alert rooms if necessary. There are no cooking facilities in the room, and not even kettles are allowed is my understanding. However, the tenants can be short term or require some supervision (albeit not on site), so there is likely a higher than usual risk of a fire starting in a room.

One benefit of a full alarm system as fitted to another HMO she has is that it will show tamper and individual room alarms, but obviously there are significant extra install and maintenance costs involved with having one of those when it's not needed.
 
Having a bit of a mare at the moment with a small 2 story HMO (6 single rooms with shared kitchen) which was fitted relatively recently (2016 or so I think) by someone else but I was asked to do an annual certificate for one of my regular landlords as she was being fleeced by a 'professional' company.

Last year was fine with no issues and only thing that came up at this year's inspection in January was a missing detector in one of the rooms. Also appeared someone from the management company had replaced some with incompatible models, but they did all work.

Since then there have been several false alarms leading to call outs late at night by the management company engineers, who did nothing but unplug them all and push it back to the landlord, claiming a 'loose connection' on one visit, and a 'faulty alarm' on another.

Since then I've replaced the incompatible ones, redone all the original dodgy terminations at each fitting, and yet apparently they were going for 2 hours last night.

It's a Grade D LD1 system, with detectors in each bedroom, up and down hallways, and heat in kitchen. There is no detector near the kitchen that could be picking up cooking fumes.

The units are all Firex, mostly KF20s with one KF20R and a KF30 heat alarm. The oldest ones are still fine until 2028, and they all had batteries in place.

I was able to test continuity from the start of the circuit to what I think is the end, though didn't do IR testing as some units were still in place. They all tested fine with test button and smoke can.

The claim is that the hush button isn't working when they do go off, but since there are no staff on site and the tenants are not the most reliable it's hard to get accurate information.

My suspicion is that at least one of the tenants is smoking a certain substance and/or buggering with the detector, but hard to prove that of course. It's not very local and access is difficult too as the housing management company has to be there to get access to the bedrooms.

Are false alarms that cause multiple hour long alarming sessions out of nowhere that common with these alarms? If so what are possible causes?

Any suggestions for other tests that could be done to identify or confirm that there is no fault in the system?

I've read through the latest 5839-6, and for existing HMOs, they actually only recommend LD2, so I'm toying with the idea of suggesting the room ones aren't interlinked with the others, but wary of reducing the existing protection without very good reason.

Although each room has fire doors, it's really only a small house, and the hallway smokes should be enough to alert rooms if necessary. There are no cooking facilities in the room, and not even kettles are allowed is my understanding. However, the tenants can be short term or require some supervision (albeit not on site), so there is likely a higher than usual risk of a fire starting in a room.

One benefit of a full alarm system as fitted to another HMO she has is that it will show tamper and individual room alarms, but obviously there are significant extra install and maintenance costs involved with having one of those when it's not needed.
First things first, speak with local licensing authority and check that current coverage meets local licensing requirements; just in case they ought to have a 5839-1 system for that communal areas, once it's confirmed if thry don't only then would I look at proceeding with any changes.

Dutyholder should also have an FRA you can refer to which should also give guidance on the recommended setup.

Have to tried swapping out the system as a whole for another brand, in case it's something with the particular brand of alarm?
 
How frequent are these false alarms?

You may be right that it’s picking up someone smoking, but of course no one will admit to it.

Are any of them in close proximity to electric heaters that are maybe burning dust off, or a spillage inside the heater?
 
How frequent are these false alarms?

You may be right that it’s picking up someone smoking, but of course no one will admit to it.

Are any of them in close proximity to electric heaters that are maybe burning dust off, or a spillage inside the heater?

Well I was told there had been none in the last year, but since the visit in January there have been at least 3 supposedly, all late evening and for multiple hours.

The most recent one was after I'd visited and checked all connections and replaced any dodgy or possibly incompatible detectors too.

Seems like the management company don't keep proper records so printed off a log book pinned to the notice board for future use.

It's Central heating, and the sensors aren't located anywhere a heater would likely be plugged in.
 
First things first, speak with local licensing authority and check that current coverage meets local licensing requirements; just in case they ought to have a 5839-1 system for that communal areas, once it's confirmed if thry don't only then would I look at proceeding with any changes.

Dutyholder should also have an FRA you can refer to which should also give guidance on the recommended setup.

Have to tried swapping out the system as a whole for another brand, in case it's something with the particular brand of alarm?
I'm not sure things are quite as clear as they should be. The local council licenses HMO I believe and just specifies 'interlinked alarms', but doesn't seem to have anything very clear in writing. It's basically a Victorian terrace house, so communal areas are only the hallways and stairs.

My landlord owns the property and then leases to a management company who places the tenants in the rooms as necessary.

Another brand is an option, but gets expensive for 8 alarms, especially if we go Grade D1 as recommended by 5839.

To be honest, I'm not sure there ever was a FRA - or if it was it was likely a copy and paste job rather than the type required by 5839.

The electricians who installed everything didn't exactly do things well - or bother with things like enclosures around their choc blocks in the ceiling or anything novel like that. They did install emergency lighting, though only from local lighting circuits and with no test switch facility 🙄


I will dig a bit further with landlord though.
 
The Firex alarms work purely on the interlink cable, which I always assumed becomes live when one alarm triggers, like a switch.

Or is it more sophisticated than that with resistances or similar?

One of the engineers on their late night visit claimed a 'loose connection' in the ceiling caused one of the false alarms, but unless the interlink cable was touching permanent live I don't see how that would cause a false alarm if I'm understanding how the interlink works?
 
I didn’t think the interlink cables carried mains voltage??? I might have to check that, but then again, I don’t know these particular detectors manufacturer.

One of the model numbers you gave on OP had an “R” ….. Is this to denote a radio type interlink?
If so, could it be receiving interference? Does it need “house coding” like Aicos do?
 
I didn’t think the interlink cables carried mains voltage??? I might have to check that, but then again, I don’t know these particular detectors manufacturer.

One of the model numbers you gave on OP had an “R” ….. Is this to denote a radio type interlink?
If so, could it be receiving interference? Does it need “house coding” like Aicos do?

Firex are now owned by Kidde, so a fairly reputable brand or so I thought.

The R just means lithium battery (for some reason) rather than 9V backup.

I guess the interlink might well be 9V too - but I assumed it was just either a voltage on the cable or not, which makes me think that a false alarm for 2 hours seems unlikely based on wiring to me...
 
Is anyone vaping as this is a highly effective way of testing Part 6 detectors I do it all the time. Cigarette smoke isn't very effective to activate them but vaping certainly does.


Given the smell every time I've been there, I suspect more than vaping, but useful to know - it may be that they don't think they are 'smoking' so think its safe.....

I'd assume unless they are hotboxing that the alarm wouldn't usually last for 2 hours though?

So far it's always seemed to happen late at night (naturally)
 
Probably a bit too late and/or expensive option would be to replace them all with Aico smart link alarms, which can be polled remotely via the internet, as to which detector caused the alarm, at what time, whether the hush bottom was pressed etc.
 
Got a call back from Kidde tech today so kudos to them for a quick response.

Seems like the interlink uses a low voltage signal, but in theory anything over 7V can cause it - and a loose neutral can cause issues.

I did redo all the connections in the ceiling though from the "traditional" bare choc block to wagos in enclosure, so suspect the issue is either with cable damage, or user interference.

The Firex apparently do have a handy alert memory mode, both in LED and audible form. This applies to their KF10, KF20, KF30 models and might be useful for anyone searching the forum in the future:

If a unit has entered into alarm (detecting smoke in the case of smoke alarms or heat in the case of the heat alarm models within the last 24 hours) and then come out of alarm; it will be set into the alarm memory state; comprising of a visual state (3 flashes of the red LED every 40 seconds lasting a maximum of 24 hours) and an audible state (lasting indefinitely, whilst the unit is powered, until reset by the test button as described below):
When in audible memory state it will not produce a PTT (the normal temporal three sounder pattern) when the button is pressed and held. Instead of the PTT, the unit produces a fast chirp and LED flash to indicate alarm memory. Since the PTT is not produced, the interconnect signal is not sent to connected alarms and the network will not sound during that first press. When the button is released from the first press the unit will resume normal operation with the memory states cancelled. Pressing and holding the button will now produce a PTT signal (the normal temporal three pattern) and all alarms will sound as remote units.

The issue in this case is that access to all the rooms is not possible for anyone attending unless the housing management company rep is also there with keys, which is currently not possible without pre booking days in advance - Getting a straight answer out of the short term tenants as to which lights were showing on each detector seems unlikely.

Hopefully the audible memory state might last until I get there this week.

This is a case where a full system with a panel would probably be handy, since it would show tamper and room states, etc. But since there is no staff onsite and tenants are always short term of a few months at most so no-one long term who could be trained onsite, probably would end up more trouble/cost than its worth.

I've been down the rabbit hole of documentation today, and got hold of the fire risk assessment, which calls for Grade LD2 - but includes in that interlinked smokes in each bedroom.

The key in the LACORs guide which everyone seems to refer back to in their guides (even though it hasn't been updated since 2008) is whether this is a 'shared house HMO', or a 'bedsit HMO', since the latter calls for interlinking in each room.

The latest 5839 in theory supersedes LACORs, but doesn't make things much clearer on that score.

The ideal would be a system where the bedroom ones delayed triggering all alarms, but that doesn't seem to be possible outside of a full panel setup, unless someone knows of a maker of standalone sensors that includes that option?
 
Probably a bit too late and/or expensive option would be to replace them all with Aico smart link alarms, which can be polled remotely via the internet, as to which detector caused the alarm, at what time, whether the hush bottom was pressed etc.
Nice idea, but there isn't even broadband on site - and although the Aico system looks nice, it's very expensive when you get into the 'smart' bits of their system.

From memory of their training you can do some stuff with 5G I think, but even so seems a bit overkill for what should be a simple fit and forget option...
 
The Aico system may cost more than most, but the system can give you all the information you require without a panel, each individual alarms status can be obtained from the Audio link, if the alarm is one of the 3000 series.
 
Oh I hate the audio link…. Has it changed much?
Sounds like an old computer game loading from cassette, but at really high volume

Or 56k modem, but I wanted to go further back than that.
 
Probably a bit too late and/or expensive option would be to replace them all with Aico smart link alarms, which can be polled remotely via the internet, as to which detector caused the alarm, at what time, whether the hush bottom was pressed etc.
The smartlink setup would be an expensive option the alternative with the Aico 3000 series you could use the audiolink to download the info from the suspected detector or all the detectors

WIN_20220222_12_52_32_Pro (2).jpg
 

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