You seem to have gone to lots of effort promoting the use of ionisation alarms in kitchens. Something which is contrary to all formal guidance on the subject.
I don't doubt that you may be able to get satisfactory performance from an ionisation alarm in *some* kitchens, however it proves impossible in many.
I was not aware anyone was suggesting they were.
True, but? Professional installers are not going to do it, and DIY installers would in general be better off not trying. Just because something can be does, it does not mean it should be done.
I've not promoted it at all. Just explained it's a way to make them work.
we already know what manufacturer guidance is & why
I'm sure some are too small.
we know that already, there are legal requirements on that
That makes no sense. There are lots of battery ionisation detectors in use. It's trivial to make them work ok. Better off not doing so is a senseless conclusion.
Obviously. But when there's the benefit of your fire detection system working properly, that's a good reason to do it. You seem to lose the ability to do basic reasoning when shown anything outside of government/manufacturer guidance.
I would call over a dozen posts in the same thread arguing the toss will all comers some form of "promotion"!
Again, not just the manufactures, but also the building regs, the British standards, and the advice from the fire brigades.
The "why" is bleeding obvious, its a procedure which if followed will yield a working and effective system in the large majority of situations
- there is no conspiracy theory here.
or the wrong shape, or have the wrong airflow, or the implications of false alarms are too high to risk (HMOs etc)
Why is doing a job properly "senseless"? Why bodge something that should it fail could literally cost someone their life?
(where "fail" would include being over sensitive and alarming everything the toast burns, or someone fries something)
That is because the official guidance on this is going to give the best chance of the system actually working properly, and will do so without lots of trial and error.
You seem to have lost the ability to judge guidance on its merits.
The regulations set out a layered structure for alarm placement based upon many years of testing and alarm characteristics. The order of priority is upstairs landing first, downstairs hallway second and kitchen third. This is designed to maximise alarm effectiveness and minimise nuisance alarms.
These days optical sensors are preferred to ionisation because of greenywails over the minute amount of radioactive materials they contain and some countries already ban them.
In most domestic fires both optical and ionisation detectors are likely to alarm at similar times. In the case of the most common kitchen fires the landing/ hall alarms will go off first, the heat detector a bit later. If you try to put an ionisation alarm in a kitchen and find somewhere it doesn't nuisance alarm it is no more likely than the hall alarms to go off first in case of a real fire as it must be positioned in still air to avoid the nuisance alarms.
The layered approach allows for timely alarms on real fires but minimises the nuisance alarms that cause people to disconnect alarms. There is always a conflict between nuisance alarms and rapid real detection and the suggested placement minimises the first and achieves the second.
If you are going to fit only one alarm (not a good idea) it should be on the landing ceiling at the top of the stairs. Putting an ionisation detector in a kitchen in a carefully chosen position so it won't alarm is a somewhat bizarre approach.
not so. I like doing experiments, and extend that to diy things now & then. I always find it odd how people who have not done the experiments and have thus not gathered any facts tell me how it must be when they obviously don't know. And it always happens.
of course. It also misses tricks though. It's not a perfect system.
It does alarm, and does so much faster than a heat detector. It only alarms when it should, at least IME so far, and it's been north of a decade in 2 houses. Heat detectors are certainly better than nothing, but as fire detectors go they're the least effective type available. Any other detector technology that can be got to work beats them on safety by a good margin.
As I intimated before, I do wonder to what extent that depends on what and how you cook.
Having a spare battery-only ionisation alarm I've been seeking the magic spot for the past few days. This is in a 5.8m x 2.8m kitchen. I found nowhere near[1] the ceiling where it didn't give false alarms when the hob/oven were chucking out products of combustion[2].
To be fair, we need a better cooker hood. But the extractor fan ain't bad. But that needs to be set against the fact I had no chance to see how it reacted when the grill was also in serious cancer-inducing mode.
It also went off when on the worktops.
But it was quiet when on the floor.
[1] I drew the line at actually fixing it to the ceiling: it was on top of wall units or a ladder
[2] eg searing aubergines coated with olive oil, sealing beef, getting the pan for Yorkshire pudding _seriously_ smoking
Your experience is I suspect considerably less than that of those who wrote the instructions.
They are not the least effective but the most appropriate unless you fall into the trap of assuming more nuisance alarms = good. The primary source of kitchen fires is unattended pans on hobs, especially those containing fats.
The vast majority of kitchens will with normal cooking produce unacceptable numbers of nuisance alarms if either ionisation alarms or optical ones are fitted in them. Kitchen fires are usually fast developing and temperature detectors work well if the primary sensors in the hallways don't get anything to detect - if the kitchen door is closed for example.
The most sensitive is not the best if it produces unacceptable rates of nuisance alarms, it will simply be disabled by the occupants.
obviously that does not make any difference to whether it can alarm when real risk occurs & avoid false alarms. A wide range of cooking foods & styles has been done, including at times the irresponsible & inedible.
5.8m is in the ballpark of the distance from oven to detector I used. If your oven's in the centre you won't get 5.8m away of course.
I'm sure the instructions are the result of far more experience than 2 detectors for over 10 years. Ionisation alarms have been in use since 1951, about 67 years so far. That does not of course mean they've tried the approach I and however many others have. They also may have tried it & judged it too tricky for people who struggled to follow even very basic instructions. We'll never know. Methods that work better than the standard government sanctioned advice are hardly unheard of.
then I'm curious to hear of a less effective type currently in production. I can only think of historic types like the larm-u & homemade polythene detectors that would be less sensitive.
that's true until one finds something that works better. That something has been found.
that makes no sense that I can see
I'm sure we covered that already
no, they don't. They only detect once a fire is already alight & chucking out lethal fumes. An ionisation alarm at a suitable distance detects the fire before it catches light. That is why they have seen such widespread use, rather than cheaper temperature alarms.
Obviously your statement makes no sense whatsoever.
A kitchen used to make tea and reheat things in a microwave and not much else, will prove less problematic that one where a fuller range of cooking happens.
An alarm placement that suppresses real alarms will likely suppress false ones as well.
Do you frequently cook in Robin's kitchen?
5.8m, well you should have said, that makes it so clear. There we were trying to factor in things like airflow, and placement of doors. Ceiling heights, and what impact extractor systems might have. If we had known all we needed was the magic distance we could have saved so much extra effort.
We should tell the BRE, they can stop wasting all that effort on elaborate testing:
Since nothing you say in this post shows sense I don't need to answer it. I can only conclude you have some sort of irrational emotional reaction to any new ideas, you respond to them irrationally every time.
I just find it a bit comical when Dunning Kruger is so obviously at play...
Stacked up on one side of the debate, we have reams of official guidelines, loads of research on fire detection and smoke alarm performance (in a variety of settings with different fire profiles, and different combustible materials). Then on the other side we have someone claiming a solution that he cooked up and has tried twice, is superior to the mandated guidance included in the building regs etc, based on the decades of aforementioned research, the results of empirical tests, and observations made from the aftermath of thousands of real world fires.
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