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FIRE SERVICE AND GENERAL FIRE SAFETY TOPICS => Fire Safety => Topic started by: Hi Tower on August 04, 2010, 12:28:01 PM
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Can someone advise me if BS5839-1 contains advice on the grading of AFD? I can readily find it in BS5839-6; but am puzzled of its ommission (or my failing eyesight) in BS5839-1.
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There is no grading in a part 1 system.
All detectors are hard wired + battery backup. All control equipment etc is done to the same standard. i.e. There is no 'cheap version' of a part 1 system. The main difference in the provision is via 'category'.
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Further to Civvy's excellent reply. The Grades in Part 6 is more to do with the 'quality' (in terms of monitoring, power back-up etc. etc.) of equipment used in the system. Part 1 basically only has one level of 'quality' so there aren't any Grades.
The Category of system in both Parts gives you a recommendation of which areas in a building needs the equipment.
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Absolutely - if you want a lower tech, lower cost system you have to use Part 6 kit, which of course isn't strictly meant for commercial use, but in smaller premises with a suitable risk assessment can be used (but it's the assessors neck on the line as they have to justify the deviation from the benchmark i.e. using a Part 1 system)
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if you want a lower tech, lower cost system you have to use Part 6 kit, which of course isn't strictly meant for commercial use, but in smaller premises with a suitable risk assessment can be used (but it's the assessors neck on the line as they have to justify the deviation from the benchmark i.e. using a Part 1 system)
Can you explain why it isn't strictly meant for commercial premises? In terms of risk many commercial premises will be lower risk than residential as people won't be sleeping there.
and
are there any stats out there that show how many failures of alarms (each grade) have occurred over a period so that a determination of the risk can be calculated.
Lastly; what other factors need to be considered in terms of having a grade A over and above a C grade system if it can be proven there reliability is not detrimental?
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I cannot now quote properly so have respond to ABs point about deviating from bench marks this way.
I cannot highlight the key areas in this text as I cannot now scroll down to and edit any text below the window. (Not very technical explanation) Is the website in meltdown?.
In short the guide allows for discretion so therefore using discretion is not a failure to follow guidance.
The BS does provide for deviation as contained in the following. A5 in particular.
4 Need for a fire alarm system
4.1 CommentaryThe need for a fire alarm system in any specific building will normally be determined by the authority
responsible for enforcing fire safety legislation in that building and/or by a fire risk assessment carried out by the owner, landlord, occupier(s) or employer(s), as appropriate. In general, it is appropriate to install some form of fire alarm system in virtually all buildings, other than very small premises that are relatively open-planned so that any fire will be quickly detected by occupants, who will be able to warn others by word
of mouth or simple mechanical devices such as hand-operated bells.
Manual fire alarm systems are often sufficient to satisfy legislation in workplaces in which no one sleeps.
Automatic fire detection is usually required by legislation to supplement the manual system in premises in
which people sleep. Automatic fire detection might also be necessary to satisfy legislation under the following circumstances:
a) where the automatic fire detection forms part of a fire engineering solution;
b) where fire protection systems, such as door closing facilities or smoke control systems, are to be operated
automatically in the event of fire;
c) where the low level of occupancy of a building, or part of a building, is such as to create the potential
for fire to prejudice means of escape by occupants before they are aware of the fire.
BS 5839-1:2002+A2:2008
10 © BSI 2008
Section 1
Automatic fire detection is also commonly used to protect property by ensuring the early attendance of the
fire service, as a result of the summoning of the brigade by occupants of the building or by transmission of
fire alarm signals to an alarm receiving centre from where the fire service will be summoned. Automatic fire
detection systems might, therefore, be required or recommended by the property insurers.
The early detection of fire by automatic means, and rapid summoning of the fire service, is also important
in premises in which people cannot readily be evacuated immediately in the event of fire (e.g. hospitals).
4.2 Recommendations
The following recommendations are applicable.
a) Where there is uncertainty regarding the need for a fire alarm system, or the Category of system that
should be used (see Clause 5) reference should be made, by the developer, potential purchaser or user, to
one or more of the following:
1) relevant part of BS 5588;
2) guidance documents that support fire safety legislation;
3) any authority responsible for enforcing fire safety legislation that applies to the premises;
4) the property insurer;
5) any relevant fire risk assessment.
b) The purchaser or user should ensure that the designer of a fire detection and alarm system is
adequately appraised of the objectives of the system and any relevant requirements of enforcing
authorities and insurers.
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NT
Thanks for the reply. What I can see so far is that advice is given within the BS (particulary 4.2 a5) that allows the risk assessor to make a risk based decision on what level of coverage is deemed necessary. The level of coverage meaning the category of AFD that is required. What I want to make a risk assessment on is the grade of AFD. For example, is there any statistics that show where a grade c AFD was installed opposed to grade A that loss of life or serious harm occurred?
I guess what i'm really trying to say to the salesman, BC or any other authority is what benefit will the money I spend on a higher spec model give me? I need proof that the failure of grade c's have caused death or injury or that they regularly fail (which is picked up at service and maintenance) and therefore their reliance is sketchy; and if it is - why can such a grade be recommended to sleeping premises?
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Not sure of any research undertaken following fire HT but I suppose it is a case of providing detection in areas where there is an identified risk of a fire starting and so providing adequate warning to help ensure a successful evacuation.
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if you want a lower tech, lower cost system you have to use Part 6 kit, which of course isn't strictly meant for commercial use, but in smaller premises with a suitable risk assessment can be used (but it's the assessors neck on the line as they have to justify the deviation from the benchmark i.e. using a Part 1 system)
Can you explain why it isn't strictly meant for commercial premises? In terms of risk many commercial premises will be lower risk than residential as people won't be sleeping there.
Because Part 6 says "It does not apply to any premises used for purposes other than as a dwelling (e.g. small shops, factories or similar premises used solely as places of work)." and as our courts like to refer to the BS as benchmarks the assessor would have to justify why they thought a system that did not conform to Part 1 and was designed for use in dwellings only was satisfactory for a workplace.
I'm not saying that you can't or shouldn't use a Part 6 system of call points and smoke/heat alarms other than in a dwelling, just that you are far more likely to need to be able to justify why this was suitable and sufficient should the premises fall under enforcement
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I think the question here AB is why, other than it saying so in the BS, would a part 6 system not be suitable?
What would you have to justify?
Other than probably zoning what does a Pt6 system not have to make it unsuitable for commercial use?
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Can someone advise me if BS5839-1 contains advice on the grading of AFD? I can readily find it in BS5839-6; but am puzzled of its omission (or my failing eyesight) in BS5839-1.
As already said it doesn't but maybe it should. I can see why it was introduced in part 6 because of the wide variety of residential premises, from the two up and two down to the mansion in the Cheshire countryside and all in between. Surely this applies to commercial premises to a lesser extent, from the High Street shop to Canary Wharf.
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Other than probably zoning what does a Pt6 system not have to make it unsuitable for commercial use?
and in particualar what evidence is their around that shows grade c systems have been detrimental in their functioning to alert relevant persons in the event of a fire so that it warrants a grade a system?
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I think the question here AB is why, other than it saying so in the BS, would a part 6 system not be suitable?
What would you have to justify?
Other than probably zoning what does a Pt6 system not have to make it unsuitable for commercial use?
It depends on the grade, non fire resistant cabling is permitted in a grade C system which is the most common type I've seen used in commercial premises - vast cost savings, but a lower level of redundancy than Part 1 systems (and unprotected cabling has been cited as contributing to alarm issues in some of the famous fires.)
I'm not against the use of the kit and based on the risk and the protected area to be within the maximum single zone size in Part 1 have even suggested it.
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Rational answer AB. So you could consider it sufficiently justifiable to use a Pt6 in commercial premises in grade C circumstances?
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non fire resistant cabling is permitted in a grade C system which is the most common type I've seen used in commercial premises
AB: Just to quantify your statement above are you saying that in most commercial businesses you visit that non fire resistant cabling has been used opposed to fire resistant cabling as required in a Grade A system. Does this mean that most commercial businesses out there are ignoring BS5839-1 and installing grade c systems under a part 6? or is it i wonder in most cases fitted when the AFD is installed after the original build?
Either way it seems that deviation from the standard is regularly happening
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Rational answer AB. So you could consider it sufficiently justifiable to use a Pt6 in commercial premises in grade C circumstances?
I consider it justifiable. Even as far as grade D in certain circumstances such as giving warning to persons on a mezzanine/inner room conditions.
I believe that the down side is that there is no particular test to test the actual function of the detector. You can press the button, and that proves that it makes a sound when that button is pressed, but without the pt 1 test regime there will be no proof that the sensing element works. There is no reason why you couldn't have it tested in such a way though, and I would be tempted to say that a risk assessment should show that this test is necessary regardless of what the BS says for a part 6 system.
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non fire resistant cabling is permitted in a grade C system which is the most common type I've seen used in commercial premises
AB: Just to quantify your statement above are you saying that in most commercial businesses you visit that non fire resistant cabling has been used opposed to fire resistant cabling as required in a Grade A system. Does this mean that most commercial businesses out there are ignoring BS5839-1 and installing grade c systems under a part 6? or is it i wonder in most cases fitted when the AFD is installed after the original build?
Either way it seems that deviation from the standard is regularly happening
No - I didn't make it very clear ;D I meant that in the premises where I had found pt 6 systems used (normally single storey small retail units) they used non FR cabling.
Although I still find the odd part 1 system that is under 25 years old with call point and detector cabling in non FR (because IIRC correctly they could until 2002 although it wasn't best practice).
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I think a Part 6 grade C system with call points and a few smokes is justifiable for the large number of premises that haven't had a fire alarm (fell outside the full scope of the FP Act) but are just on the wrong side of size/layout for verbal alarm.
The preferred standard would still be a Part 1, but where a lot of these shops (and similar office buildings) are operated by SME's then the most cost effective (but suitable and sufficient) solution should be made available.
Grade D for access room with no need to be audible or trigger warning throughout the whole premises can be fine and is illustrated in the DCLG entry level guide.
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Thank you for your replies - most helpful - it does still make me wonder why the grading solution hasn't been incorporated into the part 1 BS?
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Slightly different query but still on the track of grading - I cannot see in BS5839-6 any reference for when the back up supply batteries of grade D smoke alarms should be replaced. Clause 26 mentions cleaning but nothing else for routine maintenance. Any reference welcome?