Which smoke alarm type for which room.

[muffking]

I could do with knowing which type of smoke alarm should be used an where.
My understanding is that ionising alarms should be used in bedrooms & hallways, but heat alarms should be used in/near the kitchen area, although Aico also suggest a heat alarm in garages.

My main questions are why is a heat alarm recommended for a garage and when would you use an alarm with an optical sensor?

 

[Risteard]

Don't use ionisation in halls - use photoelectric (optical).

 

[JohnW2]

My main questions are why is a heat alarm recommended for a garage ...

I suppose it depends upon what goes on in one's garage. Heat, rather than (any type of) smoke alarms are recommended in kitchens, since smoke etc. from cooking can set of any type of smoke alarm. If things were going on in a garage (e.g. grinding, welding etc.) which could result in smoke/similar, then I suppose the same argument would apply as in a kitchen. Also, I suspect (but do not know) that a purely petrol fire might result in little smoke (at least, until it involved things other than the petrol).

Kind Regards, John

 

[JohnW2]

Don't use ionisation in halls - use photoelectric (optical).

I have to say that no matter how many hundreds of times I read about the pros and cons of ionisation and optical smoke detectors in different parts/rooms of a house, I still don't come away with any really clear practical idea.

What matters is the 'type of fire' ('smouldering' or 'flaming') and, quite apart from the fact that there will clears be 'shades of grey' in between the extremes, it can only be a guess as to what sort of fire is most likely in which part of a particular house. Apart from anything else, houses vary a lot so what might be true of one man's living room or bedroom might be true of another man's hall or landing - so no 'generic' advice is like to be possible for any house.

I think it's only a matter of speed of operation - I think either type of detector will be triggered by a significant fire of any 'type', although one might trigger more quickly with a particular type of fire.

Kind Regards, John

 

[Risteard]

No the advice is invariably for optical in halls and landings. Certainly a hall in close proximity to the kits and should never be an ionisation detector as this will lead to false alarms and the detection being removed/disabled.

 

[JohnW2]

No the advice is invariably for optical in halls and landings. Certainly a hall in close proximity to the kits and should never be an ionisation detector as this will lead to false alarms ....

As I said, it's nothing like as simple as that, certainly when put forward as a generalisation.

I'm not sure that 'proximity to kitchen' is necessarily the thinking behind the common advice you mention but, even if it were, it's clearly not the case that optical detectors are immune from being triggered by 'kitchen activities' (otherwise we would/could use them in kitchens).

It seems to me that anyone who thinks that the generic advice/recommendations are straightforward is either naive or hasn't thought very much.

What, for example, about my hall - which is not 'in close proximity to a kitchen' (at least one room and two doors away) and which, because it is pretty large, contains much the same sort of furniture and furnishings as does my living room or dining room? Can you give me a logical explanation as to why different types of detector should be recommended for the hall as compared with those other rooms/areas? On the other hand, my dining room is in fairly close proximity to the kitchen (just one door between the two) - so what would be your justification for saying that it should not be considered in the same way as you are suggesting for a hall?

Kind Regards, John

 

[muffking]

Thanks guys.
I've got regular ionising smoke alarms in both up & down halls and nothing in my garage. Based on your info I'm looking at changing the upstairs hall to Optical, the downstairs hall near the kitchen to Heat and adding a Heat alarm in the garage where I keep 3 motorbikes (greedy I know).

 

[Risteard]

the downstairs hall near the kitchen to Heat

You must not use a heat detector for the hall. That would wholly fail to comply with BS 5839-6.

You should get a competent contractor to do this - it's not simply a matter of putting random alarm types in random places.

 

[muffking]

Landing and hallway smokes are already in situ, but are both ionising alarms. The plan was to renew/upgrade them whilst I add one to the built in garage.
So unless I replace with Optical alarms is there any benefit of using Multi Sensor alarms instead?

 

[JohnW2]

You must not use a heat detector for the hall. That would wholly fail to comply with BS 5839-6.

Indeed - it would not make sense to have anything other than an ionising or optical detector in the hall.

I think you have probably confused the OP by saying that he should have an ionising detector in the hall if it is close proximity to a kitchen, because of the risk of false alarms (from cooking). If he believed that argument, he would logically think that he should have only a heat detector is the hall if it is 'in close proximity to a kitchen', since even at optical detector would be at risk of false alarms due cooking - but that, of course, would not be appropriate.

Kind Regards, John

 

[muffking]

I think you have probably confused the OP by saying that he should have an ionising detector in the hall if it is close proximity to a kitchen, because of the risk of false alarms (from cooking). If he believed that argument, he would logically think that he should have only a heat detector is the hall if it is 'in close proximity to a kitchen', since even at optical detector would be at risk of false alarms due cooking - but that, of course, would not be appropriate.

Kind Regards, John

That's exactly how I interpreted it, thanks both for the clarification.
I'm now looking at changing both interconnected Ei Ionising alarms in the landing & hallway for the newer Aico Optical alarms and adding Heat in the garage.

 

[JohnW2]

That's exactly how I interpreted it, thanks both for the clarification.

I think the confusion arose because, although it's true that one often sees optical, rather than ionisation, detectors recommended for a hall, that is not for the reason that Risteard suggested (proximity to kitchen) - since, it it were, it would be more-or-less as much a reason for not having an optical detector in a hall as for not having a ionisation detector there.

I'm now looking at changing both interconnected Ei Ionising alarms in the landing & hallway for the newer Aico Optical alarms and adding Heat in the garage.

That sounds reasonable to me.

Kind Regards, John

 

[Risteard]

I think you have probably confused the OP by saying that he should have an ionising detector in the hall if it is close proximity to a kitchen

I clearly stated that he MUST NOT use an ionisation detector near a kitchen.

 

[JohnW2]

I clearly stated that he MUST NOT use an ionisation detector near a kitchen.

You did - and, if you believe that proximity to a kitchen (hence the risk of false alarms due to cooking) is the issue, you could equally well have said that one "MUST NOT use an optical detector near a kitchen". Hence, if the hall is near a kitchen, that would only leave a heat detector - which even you don't believe is appropriate for a hall.

Kind Regards, John