FireNet Community
FIRE SAFETY => Fire Alarm Systems => Topic started by: John Webb on November 11, 2010, 09:59:47 PM
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Just picked up this item on the York Post Web Site - see http://www.yorkshirepost.co.uk/localnews/Blaze-alarm-covered-in-cling.6621294.jp (http://www.yorkshirepost.co.uk/localnews/Blaze-alarm-covered-in-cling.6621294.jp).
In summary two 20 year old men were rescued from a flat after leaving a fat pan on and falling asleep. FRS called by a neighbour whose alarm was set off by the spreading smoke. They found a detector in the fire flat covered with cling film......
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I'm sure I'm not alone but in the past weeks FRAs I've found detectors covered with the blanking caps, rubber glove and cling film at three different venues! For two of these it was due to work going on in the area some time ago when they were covered and never uncovered, the story above though is probably a case of the smoke alarm being in the 'wrong' position and constantly going off - given some of the recent debate I wonder if a heat detector would have actuated in this case?
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Re covering detectors - at the Fire Research Station we moved into new buildings in the late 1970s. These had detectors in plant rooms. The first two years of occupation we had some dozen+ 'unwanted alarms' due to workmen doing hot work without telling us. We had signs put on every plant room door saying 'Automatic fire detectors fitted - contact switchboard before any hot work' or something similar. On being informed of hot work we'd tape a polythene bag over the appropriate head(s) and put a note in the WFB logbook; at the end of the day the WFB would remove the bag(s). Result was a reduction in unwanted alarms to 1 or 2 a year!
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Re covering detectors - at the Fire Research Station we moved into new buildings in the late 1970s. These had detectors in plant rooms. The first two years of occupation we had some dozen+ 'unwanted alarms' due to workmen doing hot work without telling us. We had signs put on every plant room door saying 'Automatic fire detectors fitted - contact switchboard before any hot work' or something similar. On being informed of hot work we'd tape a polythene bag over the appropriate head(s) and put a note in the WFB logbook; at the end of the day the WFB would remove the bag(s). Result was a reduction in unwanted alarms to 1 or 2 a year!
Which goes to show that with a well-planned and well-understood management system in place there are cheap, quick and sensible solutions to many problems.
I would also say that in my opinion that the temporary application of clingfilm or a polythene bag is a better solution than temporarily totally removing/isolating a detector from the system. At least if there is a fire the clingfilm/polythene should melt pretty quickly and the smoke detector be able to operate.
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We find covered detectors on a regular basis.
Most common causes we find are that:-
People cover detectors because of false alarm issues (ie poorly sited detectors going off every five minutes because of cooking fumes for example)
Particularly since the smoking ban we have come across more people suruptiously smoking nearby a detector!
And finally workmen have been in and covered the detectors whilst doing hot or dusty works and the RP hasn't checked to see if the detectors are uncovered once the work men have left for the night!
John Webb's comments demonstrates how this problem can be managed properly and safely
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A couple of earlier posts have both mentioned 'poorly sited' detectors as being the cause of unwanted alarms.
In my opinion it is rarely possible to successfully re-site an automatic smoke detector to definitely prevent operation from cooking/showers etc. No matter where you site it and with compliance with the BS recommendations it can still give problems in many cases. You can sometimes improve things by re-siting, but rarely totally eradicate the problem.
More success is generally found by improving extract ventilation so that the fumes/steam is less likely to affect the detector, although one wonders if this also means that any smoke from a fire will also be prevented from reaching the detector!
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A couple of earlier posts have both mentioned 'poorly sited' detectors as being the cause of unwanted alarms.
In my opinion it is rarely possible to successfully re-site an automatic smoke detector to definitely prevent operation from cooking/showers etc. No matter where you site it and with compliance with the BS recommendations it can still give problems in many cases. You can sometimes improve things by re-siting, but rarely totally eradicate the problem.
More success is generally found by improving extract ventilation so that the fumes/steam is less likely to affect the detector, although one wonders if this also means that any smoke from a fire will also be prevented from reaching the detector!
In some cases it is near impossible Wiz to relocate (ie - small utility rooms for example) but in others it's a matter of moving it from the ideal location (ie - centre of room) and relocating it in the corner 500mm out provided you are still getting your 7.5M radius.
Yes,I'm here cause the other place is up the left (and I thought i'd see what it was like to be a mere minion!!)
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In my opinion it is rarely possible to successfully re-site an automatic smoke detector to definitely prevent operation from cooking/showers etc. No matter where you site it and with compliance with the BS recommendations it can still give problems in many cases. You can sometimes improve things by re-siting, but rarely totally eradicate the problem.
I see where you coming from...
That said I have seen detectors placed in some very silly positions in the past the classic being the SD right outside the door to an ensuite bathroom in a hotel bedroom.
The hotel was having so many false alarms that in the end they had to get the fire alarm engineer to re-site the detectors further away - low and behold it cured the problem
So I accept if designed and installed properly in the first place you shouldn't get AFAs from a fire alarm system due to poorly sited detectors.. IF designed and installed properly!
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In my opinion it is rarely possible to successfully re-site an automatic smoke detector to definitely prevent operation from cooking/showers etc. No matter where you site it and with compliance with the BS recommendations it can still give problems in many cases. You can sometimes improve things by re-siting, but rarely totally eradicate the problem.
I see where you coming from...
That said I have seen detectors placed in some very silly positions in the past the classic being the SD right outside the door to an ensuite bathroom in a hotel bedroom.
The hotel was having so many false alarms that in the end they had to get the fire alarm engineer to re-site the detectors further away - low and behold it cured the problem
So I accept if designed and installed properly in the first place you shouldn't get AFAs from a fire alarm system due to poorly sited detectors.. IF designed and installed properly!
It also depends on the category of the system (and whether it has to be a smoke) but generally it's down to the installer/designer taking the easy option of just nipping into the room and back out again from the corridor.
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Buzz & MF, I understand what you are both saying.
My experience is that better siting rarely eradicates the problem (cooking fumes and steam can have a fair old spread) but, yes, of course, better siting can reduce the problem. And, yes, the detector should be installed in the best possible position (in this case to reduce unwanted alarms) from the beginning (with due respect to BS recommendations).
I also, obviously, agree that it is better to have the smoke detector 7.5m away from the source of the problem and only 500m away from corner walls, rather than the centre of the room.
IMO the cause of problems with poorly sited detectors is rarely the fault of system designers. They just mark detector positions on drawings and generally the scale of these drawings is so small that they can normally only indicate that a detector should be installed somewhere in a particular space or area. Often there are numerous other symbols for equipment on the drawing as well and it can all become a bit confusing.
IMO it is the installers, in this case, who are often to blame. And all because they often don't know anything about the BS recommendations. Even the best 'proper fire alarm specialists' will still use electrical installers rather than fire alarm engineers to install the cabling, and the cable installers end up determining the installed detector position. They normally look at the drawing and install the wiring to exactly the point that it appears to be shown on the drawing. They need to learn that the detector positions shown in any space/area of a drawing is just a generalisation and that the 'correct' position needs to be chosen with careful due regard to obstructions, potential causes of unwanted alarms etc., but with regard to the BS recommendations for positioning.
In my experience, the better projects are invariably those where a proper fire alarm engineer visits site and 'marks' the exact required detector positions on the ceilings before the cable installers even begin their work.
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Just picked up this item on the York Post Web Site - see http://www.yorkshirepost.co.uk/localnews/Blaze-alarm-covered-in-cling.6621294.jp (http://www.yorkshirepost.co.uk/localnews/Blaze-alarm-covered-in-cling.6621294.jp).
In summary two 20 year old men were rescued from a flat after leaving a fat pan on and falling asleep. FRS called by a neighbour whose alarm was set off by the spreading smoke. They found a detector in the fire flat covered with cling film......
usually find the good old rubber glove,shower cap,masking tape etc etc.
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To bring this thread back online does anyone have any examples of prosecutions of persons found to have purposely covered a detector.
I'm talking workplaces obviously because it is an offence under H&SAW Act.
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Not if they're covered in a controlled and managed manner so as to avoid false alarms during for example - refurbishment works.
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To bring this thread back online does anyone have any examples of prosecutions of persons found to have purposely covered a detector.
I'm talking workplaces obviously because it is an offence under H&SAW Act.
No its not. It could be an offence under the regulatory reform (fire safety) order if in england or wales or classed by some police farces who treat it as criminal damage or vanadlism depending on how the detector has been tampered with.
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Are you referring to Article 23 then, because I also am aware of an individual prosecuted under H&SW Act.
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Yes it happens from time to time intentionally. With addressable systems generally it is not possible for the user to disable an individual element of a multi sensor head, this level of configuration would normally require engineers access. So for example when hot work is taking place often the detectors in the area affected will be disabled and reliance placed on human supervision under the contol of a hot work permit.
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I have seen a number of fire alarm panels in the common areas of flats smashed to pieces. In one case the builder had used an addressable system and multi sensor heads to provide both the local self contained domestic alarms in the flats and a common areas alarm system using the cause and effects configurations. The system had operated, in the common areas and rather than call the landlord or engineers at 3am the panel had been smashed off the wall totally disabling all the protection in all the flats.
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Yes its quite common in HMOs to find tenants have vandalised either call points, detectors, sounders, or panel.
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But if there is no need for a common alarm system then do not install one. No maintenance, no vandalism, no confusion.
KISS.
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Oi,who are you calling stupid chummy?
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Hi All,
Maybe there is some justification for using heat detectors alongside some sort of a time delayed smoke detector in the flats. If only in an attempt to avoid provoking vandalism.
Your lucky to get a landlord to install a system in the first place, now you want him to pay more ??? ;D