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FIRE SERVICE AND GENERAL FIRE SAFETY TOPICS => Technical Advice => Topic started by: David Rooney on July 01, 2009, 04:59:22 PM
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I can't remember seeing anywhere that smoke detectors need to be 1.5 metres either side of a magnetically held open door... but we have just had a comment from a fire officer who "expected to see it".
The system is L3 + (i suppose that makes it L2)... are we really expected to install additional detectors in corridors ?
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David, the old 1.5m chestnut was done away with before the new 7273.
Tell the fire officer that you 'expected to see' Father Christmas last December and was also disappointed!
Check out 7273 thoroughly, it can alter detector spacings drastically. Don't ask me to explain it because I find it so difficult to undersatnd I just pretend 7273 doesn't exist.
The very rare L3+ category system is only specified by a select few designers and basically allows you to do whatever you want. Trust me if they don't know what they are doing, they'll have no clue whether what they get is right or not
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Check out 7273 thoroughly, it can alter detector spacings drastically. Don't ask me to explain it because I find it so difficult to undersatnd I just pretend 7273 doesn't exist.
Indeed, it is one of those that just baffles me everytime.... and I have to re-read it for every job. Detector spacings do vary quite drastically given different circumstances.
I do tend to also 'forget' that this standard ever existing ;)
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To be honest I don't know anyone that does recognise its existance .... it's an enigma wrapped in a riddle !!
We installed some salamander radio door magnets a while ago and there is a useful commissioning checklist comes with the kit which obviously we filled in ...... ;)
For a Cat A door we made sure that the unit released under the following conditions....
Normal supply fail.......... standby supply fail......... failure of both supplies..(?!).... short or open circuit of manual callpoint cct...... short or open circuit of automatic detector cct..... removal of manual call points or detectors ..... any earth fault on the system...... Blown fuses ....... Software/processor failure .... and any disablement of any callpoint or detector.....
...............honest !!
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Sounds like.. in other words, leave it closed ;D
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You may remember that I have previously highlighted my problems with 7273 on another thread in this forum.
Mr Todd answered that he thought the standard was so straightforward to understand that his proposed plans to write an 'explanation' of it were shelved.
At the time there was no other support on this forum for my complaints regarding the complexity of BS7273 and the difficulty I believed people were having in understanding and implementing it. So the matter fizzled out.
Everyone involved in fire alarm systems needs to implement BS7273 but I've never found anyone who understands it enough to be able to explain it to me.
I am pleading for everyone on this forum involved with fire alarm systems who hasn't seen it to get hold of a copy and read it.
If afterwards you understand it then please use this forum to educate those of us who can't!
However, if you, like myself, have tried and failed to unravel its mysteries and double-talk then please join my protest on this forum against this unfathomable document. Maybe someone will then listen and do something about it.
At the very least I feel that our fellow member Mr Todd could assist in this.
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David understands it, he regonised that Salamander is a Cat A device and installed it under the auspices of the the Cat A listing in 7273 part 4.
Do not forget the front bits of 7273 where it states that it overides 5839 for detector spacings.
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Jokar, I refute the suggestion that David understands BS7273 just because he recognises a Salamander as a Cat A device! This demonstrates he may understand a small part of it! Even I understand a small part of it!
I've never spoken to anyone (apart from Mr Todd) who claims to even understand even 75% of it. Where are the experts? Are you one of these? If so, can you provide a summary of the important parts of BS7273 and how to apply them to systems on these forums? We, the unknowing, would all be most grateful!
One of the small parts both David and I are aware of is regarding the modification of BS5839 detector spacings, that you now mention. I had already mentioned it on my first post on this thread and in previous posts on the forum. Unfortunately, this is just a small part of a very confusing document! Furthermore, have you noticed the bit towards the end that basically says some things recommended in it might soon need to be ignored because of impending new related standards? What a waste of paper and busy people's time and money!
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To be honest I don't know anyone that does recognise its existance .... it's an enigma wrapped in a riddle !!
We installed some salamander radio door magnets a while ago and there is a useful commissioning checklist comes with the kit which obviously we filled in ...... ;)
For a Cat A door we made sure that the unit released under the following conditions....
Normal supply fail.......... standby supply fail......... failure of both supplies..(?!).... short or open circuit of manual callpoint cct...... short or open circuit of automatic detector cct..... removal of manual call points or detectors ..... any earth fault on the system...... Blown fuses ....... Software/processor failure .... and any disablement of any callpoint or detector.....
...............honest !!
David, if I hadn't seen the '....honest !!' bit I would have asked where you found this super panel that could cope with all the monitoring and within the specific time criteria specified in the recommendations.
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Im not even sure where my copy of it is!
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Buzz, I presume you've burnt it and that's about the best thing you can do with it!
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Hands up. I havn't bought it. And based on what I have heard of it I dont think I will. I will make do with manufacturers interpretations.
I have just wasted loads a cash this week on the "essential" updated BS8214. What a waste of time and money that one is. May as well just say "fire doors- follow the manufacturers instructions"
Thanks thats another £138 in the BSI till. Kerrchinggg. Next customer please.
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Prof., you are right to not waste your money on it. Apart from the difficulty of understanding it, it also asks for some things that are impossible with the equipment available today. Ridiculous! I'm just glad that many specifiers don't know of its existence. As soon as people start including it as a requirement in their specifications, things will get very interesting.
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Im not even sure where my copy of it is!
It's probably rolled up and propping open a door on the basis it burns easily and the door will eventually close.....
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David understands it, he regonised that Salamander is a Cat A device and installed it under the auspices of the the Cat A listing in 7273 part 4.
Do not forget the front bits of 7273 where it states that it overides 5839 for detector spacings.
Errrrrrr I just read the big writing on the box...!!!
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Well I've got a copy..... and similar to Wiz I raised concerns over its implications and how it could possibly be implemented practically.
We are duty bound to inform our clients of this standard in order to cover our Rss and then tell them no one in the galaxy that we know of can provide a fully compliant system.
It generally meets with blank expressions with an underlying kind of "what's the point then?" look of dismay.
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Well done David.
I am determined to get the problems regarding BS7273 out in the open.
I appreciate the people who worked on it did so with the best intentions, but if none of us in the trade can cope with it, what is the point of it?
On numerous occasions on this foruum, I've set the challenge for someone to provide an understandable summary of it's recommendations
No-one has stepped forward and until they do, I will continue to denigrate it.
I ask everyone who should understand this BS, and can't, to own up on these pages.
Only then might something happen.
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Well done David.
I am determined to get the problems regarding BS7273 out in the open.
I appreciate the people who worked on it did so with the best intentions, but if none of us in the trade can cope with it, what is the point of it?
On numerous occasions on this foruum, I've set the challenge for someone to provide an understandable summary of it's recommendations
No-one has stepped forward and until they do, I will continue to denigrate it.
I ask everyone who should understand this BS, and can't, to own up on these pages.
Only then might something happen.
So what does it actually take to get the men in black to admit they've overcooked it and rethink ??
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Ive read it and can't understand it.As an ex enforcer and now a risk assessor who isnt as technically minded as an installer i find the document frustrating, non sensical and totally unhelpful. It wouldnt help me in either role. As such I ignore it completely. Money for nothing as usual.
As for the fire officer who "expected" to see a 1.5 metre spacing (if that was the case) then I'd have to say he or she doesn't know what theyre talking about and really ought to worry about more important things. Its not often I agree with Wiz but on this subject I think he is totally correct. As far as Im concerned BS's should be free of charge, should be accountable and open to the peopel that use them and whilst I do respect and doth my cap to a lot of experts that sit on these panels I have to say a lot of it is down to an insular old boys club.
It dilutes what the BS is about. What a shame! The standards are supposed to give guidance, common sense guidance, to lay clear marks in the sand, and also offer suitable alternatives where a preferred option or method cant be achieved. They are by the very nature of what they stand for supposed to guide we mere mortals into the light, its high time that some of these experts came out and explained there logic. Im not hostile, ill listen to reasoned argument and logic, but once again a faceless panel gets paid x ammount to come up with something i think they dont actually understand. Rather like a brain surgeon - very intelligent can do wonders with brains but couldnt put up a shelf.
We need real world thinkers, not blue sky thinkers who talk the talk but never actually walked the walk
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Odd though that CFOA, who, of course, being firemen, fully understand the complexities of electronic systems (though the advice they gave previously had a circuit diagram that was not a circuit) had no problem with the standard all through the development of it, when they sat on the committee responsible. Nor did the 2 representatives of the trade (BFPSA as was) who were entirely happy. And it went out to the public for comment as well. Bit late to moan now. Avoid it at your peril and dont come moaning when the bodies are in the mortuary and you are in the dock- if you think thats melodramatic it was two deaths (one involving electronic locks that did not release and the other involving an old lady knocked over by the release of doors by MDHs) that were the last straw in causing the deveopment of this standard. Sorry we wanted locks to let people out of buildings when the fire alarm fails and the locks wont otherwise release automatically, but we thought it a good idea not to trap people in burning buidlings. Clearly, this was an over-reaction on our part given that its all too much bother to avoid trapping them.
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It's alright to say "avoid it at your peril" but when the manufacturer's haven't developed or at least haven't introduced the technology yet to achieve its requirements how do we then fair in the dock?
And who were the BFPSA members?
Perhaps we should ask them how the standard should be applied and with what control equipment......?
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Odd though that CFOA, who, of course, being firemen, fully understand the complexities of electronic systems (though the advice they gave previously had a circuit diagram that was not a circuit) had no problem with the standard all through the development of it, when they sat on the committee responsible. Nor did the 2 representatives of the trade (BFPSA as was) who were entirely happy. And it went out to the public for comment as well. Bit late to moan now. Avoid it at your peril and dont come moaning when the bodies are in the mortuary and you are in the dock- if you think thats melodramatic it was two deaths (one involving electronic locks that did not release and the other involving an old lady knocked over by the release of doors by MDHs) that were the last straw in causing the deveopment of this standard. Sorry we wanted locks to let people out of buildings when the fire alarm fails and the locks wont otherwise release automatically, but we thought it a good idea not to trap people in burning buidlings. Clearly, this was an over-reaction on our part given that its all too much bother to avoid trapping them.
Colin, I have no problem with the intent of the BS, and whilst I might have opinions that some of the recommendations seem a bit of an overkill, this is not the nub of my frustration with this BS. I can't understand why your post focuses on the actual need for the BS, when I have not read any posts on this thread that argue that it is not needed.
I have a problem in the way it is written and set out. It is too confusing. Every person I know who has read it agrees with me. Surely you would agree that it is pointless having any BS that is too difficult to understand by those that need to understand it?
I also have a problem with a BS that includes recommendations that are seemingly impossible to comply with by using the type of equipment that is currently available. Are you able to recommend an addressable control panel that has all the abilities required by BS7273 to control electromagnetic door holders via a loop-powered output unit?
It appears to me that other posters on this forum have the same problems.
I have the greatest respect for the purpose behind British Standards and I consider that mostly they are very well written considering the difficulties encountered in producing such documents.
Unfortunately, this one is a turkey!
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Do the best you can with what you have , then list as many variations to cover your rear.
All will come clear when I am retired as the kit in the field might have just caught up .
Look on the bright side at least you can upset as many consultants who want the doors included in a fire spec that reads 'complies to 5839 part 1 2002 . ;D
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..........................................Look on the bright side at least you can upset as many consultants who want the doors included in a fire spec that reads 'complies to 5839 part 1 2002 . ;D
Galeon, I'd never want to upset a consultant who wanted that! I'd be able to hide behind his ignorance as well as my own ;)
Obviously, if he wanted 'the BS we don't like to mention' I'd have to say 'well explain to me what I have to do and how I can achieve it'
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1. Our very good friends in the fire service always thought that these things totally failed safe and were nothing less than shocked to find that, notwithstanding their high standards of training in electronic systems, born of years of driving fire engines, in fact they had been totally oblivious to how they worked and universally failed to properly fail safe, as born out by your posts.
2. On the horror of realisation, they, quite rightly, wanted systems to perform as guides from home office and then dtlr and then odpm and then clg ALL, for many years, said they should and always had said so. It was a classic lack of communication between the industry and the enforcers.
3. We laid it on the line that no one had ever in the history of mankind actually paid a blind bit of notice to Government guidance on this subject established over many years, and the trade had got away with it because the enforcers did not take any interest or have any clear understanding of how the circuits actually worked. The fact that people are still happy to flaunt the guidance is evidence of this.
4. Quite rightly, the committee decided that-sorry to repeat myself-it was really not a good idea to trap people in a burning building or allow fire to spread unchecked by open fire doors, simply because of a fault on the fire alarm system.
5. The trade were not only warned of the "change", which was not a change at all, but merely a continuation of what had always been in guides on the FP Act, and were consulted over the issue of I/O units, the difficulties for which we were all not only well aware but disucssed at length. Consultation took the form of one of the largest manufacturers in the land and one of the smallest in the land to get a spread. It was agreed if thats what we wanted the trade would provide it-although contrary to postings one manufacturer already could.
6. Finally, there is clearly a misunderstanding by many regarding the interface between codes of practice and products. To clarify it is the CODES OF PRACTICE that say how things are to perform. Product standards and manufacturers then need to make products that do this. This is a fundamental and long established principle. To say, we should not ask for people not to be trapped in a burning building because people want to use products that will allow this is, frankly, stupid. Its a bit like saying that we cant have legislation that cars should have reduced emissions because cars have high pollutant emission and its all too much bother to design products that meet the requirement.
If you want to know who represented BFPSA, ask FIA. As it happens, both have been personal friends of mine for many years and they are extemely technically competent.
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There are many new elements being brought into this discussion and I will respond to them first.
a) The methods of controlling electromagnetic door releases and holds that I have used in the thirty years I have been involved in the fire alarm system industry have always been based on fail-safe principles. Not withstanding any documentation that may have been produced by the Fire Service I have always found that most fire alarm engineers understood and followed the basic principles. I will accept that the actual methods used (based on the equipment that was available to be used) were not perfect. But then again surely nothing is. Show me your solution and I'll find something with it that is not fail-safe!
I have no problem with the intent in improving the fail-safe integrity of these sort of systems. (Even if they do include things such as a time delay and warning buzzer before the release of door holders because there has been a case where someone was knocked over by a closing door. I'm sorry but in my opinion a time delay and warning buzzer will not prevent many of the type of people I see these days in Elderly Persons Homes from getting hit by a closing door.)
B) Colin Todd states that one manufacturer does already produce an I/O unit that complies with the recommendations but doesn't mention which it is. Does anyone else know which one this is? I would have thought this manufacturer would be swamping the trade press with advertisiments about being the only company with such a product. I haven't seen anything, have you?
I thought Colin may be talking about the Hochiki powered I/O unit, but unless I've misunderstood things, using this unit will provide the fail-safe requirement of fail-safe when losing power to the loop, but it still won't automatically fail-safe if there are some of the faults elsewhere on the system that 7273 recommends. Can anyone else confirm this?
C) Obviously, if new legislation requires new equipment, this shouldn't be a hurdle to making this new legislation. But I feel Colin's analogy is flawed by the fact that car manufacturers were given many years notice of new pollutant emission requirements before they were enforced. 7273 is in force now.
Notwithstanding all of the above I would confirm that the biggest problem with 7273 is that too many people have lots of trouble understanding it. They argue that it is difficult to read and is confusing.
I still await someone's explanation summary of it, to prove me wrong!
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Wiz I had a conversation with BBC a while ago and they "believed" the Notifier 3000 panel could do it but couldn't confirm at that time.
Surely if the BFPSA "reps" have agreed the principles, they should have instructed all their members to modify their panels accordingly... otherwise what's the point of the organisation?
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David, Hopefully CT will reveal the name of this equipment he knows about, and we can solve at least one problem.
There must be someone out there who knows how to comply with the BS, but I am beginning to have my doubts.
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Wiz if you use the same 240v supply as the panel and use the salamander kit wire a relay perm energised on fault and fire thats the job done.
In the scheme of things you and I know that don't help if you are a distance from the panel (which is 99.9% of the time).
So unless the above applies in relation to the panel you cant do no more than that.
I will use a judgement , and I am afraid thats all we can do.
In relation to doors closing injuring old people , I have just stopped one property whose door mags all 40 of them (not overheads) being replaced as they don't close , by a cowboy firm who rode into town.
As the premises don't close them (they are linked to the panel for closure , in fire don't you know - h&s officer). It seems they still are magnetised when called to close , a quick rub with sandpaper and a time clock to close when all the old dears are in bed was called for.
Whats worse doors that are retained and don't close or the risk it may shut on someone , well its 11.30 pm closure on this job , and if they are still coming back from the pub then at that hour , I shall get my kids to book me in to that home ;)
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Wiz if you use the same 240v supply as the panel and use the salamander kit wire a relay perm energised on fault and fire thats the job done.
In the scheme of things you and I know that don't help if you are a distance from the panel (which is 99.9% of the time).
So unless the above applies in relation to the panel you cant do no more than that.
I will use a judgement , and I am afraid thats all we can do.......................................
Galeon, I don't have 7273 in front of me right now, but I do have a copy of some very basic notes I took some months ago that I jotted down before my eyes glazed over and my small brain started throbbing. These notes seem to suggest that in a category A system the fail-safe doors should operate within the following times for all of the following circumstances affecting the fire alarm system and on any part of it:
120s - Open or short circuit
3 or 60s - Reduction of power supply voltage
32m - Failure of normal supply
17m - Failure of standby supply
120s - Open or short circuit on mcp or detector circuit
120s - Removal of any mcp or detector designed to be detachable
120s - Earth fault
120s - Fuse failure
120s - Software fault
120s - Disablement
120s - Failure of radio activated systems
Are you saying that the fault relay contacts you talk about on your fire panel operate for all of these conditions?
I welcome anyone explaining any errors, if I have misunderstood my notes.
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Wiz if you use the same 240v supply as the panel and use the salamander kit wire a relay perm energised on fault and fire thats the job done.
In the scheme of things you and I know that don't help if you are a distance from the panel (which is 99.9% of the time).
So unless the above applies in relation to the panel you cant do no more than that.
I will use a judgement , and I am afraid thats all we can do.
In relation to doors closing injuring old people , I have just stopped one property whose door mags all 40 of them (not overheads) being replaced as they don't close , by a cowboy firm who rode into town.
As the premises don't close them (they are linked to the panel for closure , in fire don't you know - h&s officer). It seems they still are magnetised when called to close , a quick rub with sandpaper and a time clock to close when all the old dears are in bed was called for.
Whats worse doors that are retained and don't close or the risk it may shut on someone , well its 11.30 pm closure on this job , and if they are still coming back from the pub then at that hour , I shall get my kids to book me in to that home ;)
Hmmm..... and how does that work when you disable a detector ?
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Assuming that your door signal is normally closed then if you use the Advanced with an Apollo 3 Channel I/O (and it's only hypothetical!!) you could tie the relay output to activate on any fire,any fault and any disablement.You could then use a closed circuit input through a small relay permanently energized by the loop that holds the contact in the required state as long as the switch (ie - the loop energized relay) is closed (ie - total panel power or loop failure = door shutting).
You would have to series the door release signal through the N/C of relay 1 (tied to the events) and the N/O of relay 2 (tied to the loop powered N/C input making it closed while power is on the loop.
If you cant assign an input to be closed going open (as opposed to the norm of open going closed) on the above you can do it with other manufacturers gear (ours for one).
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Assuming that your door signal is normally closed then if you use the Advanced with an Apollo 3 Channel I/O (and it's only hypothetical!!) you could tie the relay output to activate on any fire,any fault and any disablement.You could then use a closed circuit input through a small relay permanently energized by the loop that holds the contact in the required state as long as the switch (ie - the loop energized relay) is closed (ie - total panel power or loop failure = door shutting).
You would have to series the door release signal through the N/C of relay 1 (tied to the events) and the N/O of relay 2 (tied to the loop powered N/C input making it closed while power is on the loop.
If you cant assign an input to be closed going open (as opposed to the norm of open going closed) on the above you can do it with other manufacturers gear (ours for one).
Quiet day in the office ??!!
Apollo can't monitor a NC going open... as we found when trying to monitor a low pressure switch on a Fike system...
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Assuming that your door signal is normally closed then if you use the Advanced with an Apollo 3 Channel I/O (and it's only hypothetical!!) you could tie the relay output to activate on any fire,any fault and any disablement.You could then use a closed circuit input through a small relay permanently energized by the loop that holds the contact in the required state as long as the switch (ie - the loop energized relay) is closed (ie - total panel power or loop failure = door shutting).
You would have to series the door release signal through the N/C of relay 1 (tied to the events) and the N/O of relay 2 (tied to the loop powered N/C input making it closed while power is on the loop.
If you cant assign an input to be closed going open (as opposed to the norm of open going closed) on the above you can do it with other manufacturers gear (ours for one).
Good try Buzz, but no cigar, I think. Sorry. :(
My understanding of the BS (possibly flawed, I'll admit because I can't say I fully understand it) would require the Apollo I/O to be powered on in it's standby state with NC contacts. Which it isn't. I appreciate that your second relay (being loop powered) would drop out on loss of loop power but a strict adherance to the recommendations would reveal this to be insufficient because the I/O is not strictly fail-safe.
Hochiki do a powered I/O, so that might work in your scenario. But I still don't think it is enough.
I think that the only type of I/O that would really meet the BS is one that is powered in it's standby state and is kept in that condition by a data signal regularly being sent to it by the panel. Sort of an O.K. signal. As long as the I/O saw this O.K. signal it would remain in the standby condition. Any loss of the signal would cause the I/O to fail safe. As far as I know no-one does something like this yet.
You appear to be saying that an Advanced panel can be configured to operate an output unit for any of the fault conditions mentioned in my previous post. Can you confirm this because it will be of interest to those who use panels that can't do this. However, I still don't think it is enough based on my comments in the previous paragraph.
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Assuming that your door signal is normally closed then if you use the Advanced with an Apollo 3 Channel I/O (and it's only hypothetical!!) you could tie the relay output to activate on any fire,any fault and any disablement.You could then use a closed circuit input through a small relay permanently energized by the loop that holds the contact in the required state as long as the switch (ie - the loop energized relay) is closed (ie - total panel power or loop failure = door shutting).
You would have to series the door release signal through the N/C of relay 1 (tied to the events) and the N/O of relay 2 (tied to the loop powered N/C input making it closed while power is on the loop.
If you cant assign an input to be closed going open (as opposed to the norm of open going closed) on the above you can do it with other manufacturers gear (ours for one).
Quiet day in the office ??!!
Apollo can't monitor a NC going open... as we found when trying to monitor a low pressure switch on a Fike system...
David, did you think about using a switch monitor and the fault generated when you open circuit the EOL monitoring? Surely this would work if your panel C&E can be programmed to accept a fault input to give whatever signal you required?
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Assuming that your door signal is normally closed then if you use the Advanced with an Apollo 3 Channel I/O (and it's only hypothetical!!) you could tie the relay output to activate on any fire,any fault and any disablement.You could then use a closed circuit input through a small relay permanently energized by the loop that holds the contact in the required state as long as the switch (ie - the loop energized relay) is closed (ie - total panel power or loop failure = door shutting).
You would have to series the door release signal through the N/C of relay 1 (tied to the events) and the N/O of relay 2 (tied to the loop powered N/C input making it closed while power is on the loop.
If you cant assign an input to be closed going open (as opposed to the norm of open going closed) on the above you can do it with other manufacturers gear (ours for one).
Quiet day in the office ??!!
Apollo can't monitor a NC going open... as we found when trying to monitor a low pressure switch on a Fike system...
David, did you think about using a switch monitor and the fault generated when you open circuit the EOL monitoring? Surely this would work if your panel C&E can be programmed to accept a fault input to give whatever signal you required?
No we were using the Syncro XT analogue extinguishing system (XP95 propocol) - the system has pre programmed cause and effects for predetermined inputs depending whethere you are in the extinguishant area or not.. so a "low pressure input" would cause sounders to pulse within the area and various relays to change state and lights and whistles on the panel. Opening up the EOL just causes a general fault on that input. We could have messed around feeding outputs into inputs etc but it was a bit messy ...
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But it does look impressive....
We've just got the latest software for use with the Vega kit etc... I'll have to have a play.
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Quote from previous post:
Colin Todd states that one manufacturer does already produce an I/O unit that complies with the recommendations but doesn't mention which it is. Does anyone else know which one this is? I would have thought this manufacturer would be swamping the trade press with advertisiments about being the only company with such a product. I haven't seen anything, have you?
I thought Colin may be talking about the Hochiki powered I/O unit, but unless I've misunderstood things, using this unit will provide the fail-safe requirement of fail-safe when losing power to the loop, but it still won't automatically fail-safe if there are some of the faults elsewhere on the system that 7273 recommends. Can anyone else confirm this?
Any takers in answering the above questions yet?
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Is the problem here that we are looking at I/O's on the fire alarm system that signals the door release that meet this,as opposed to an door closer interface that take signal's from the fire alarm?
http://www.fseonline.co.uk/articles.asp?article_id=7572&viewcomment=1
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Glad you asked that question Buzz, Its what I have been wondering but not thought of the right way of asking :)
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Is the problem here that we are looking at I/O's on the fire alarm system that signals the door release that meet this,as opposed to an door closer interface that take signal's from the fire alarm?
http://www.fseonline.co.uk/articles.asp?article_id=7572&viewcomment=1
This is similar to the Salamander (except I think the Sal is better)... at the end of the day both systems are going to react on the opening or closing of a relay or relays controlled by the fire panel.
If you look at the list provided by Wiz I would think that all the faults would cause a "general fault" relay within your CIE to switch over... with the exception possibly of a software fault or the disablement of a device (quite what the power supply voltage has got to do with anything i'm not sure)
120s - Open or short circuit
3 or 60s - Reduction of power supply voltage
32m - Failure of normal supply
17m - Failure of standby supply
120s - Open or short circuit on mcp or detector circuit
120s - Removal of any mcp or detector designed to be detachable
120s - Earth fault
120s - Fuse failure
120s - Software fault
120s - Disablement
120s - Failure of radio activated systems
If your gen fault relay also switches over on software/disablement then happy days providing you run a cable from the CIE to relays within the door psu...
The problem as far as I can see is that at the moment we can't use an I/O unit on the loop to switch a door psu because it either cannot be programmed to react to all the necessary fault conditions, or won't change state in the event the loop stops transmitting data or voltage or both....
So we are back to using the panel relay (if it responds to all the conditions listed) and running more cables or using the panel relay (if it responds to all the conditions listed) and one of the radio tx systems.
.... I think.... !
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Is the problem here that we are looking at I/O's on the fire alarm system that signals the door release that meet this,as opposed to an door closer interface that take signal's from the fire alarm?
http://www.fseonline.co.uk/articles.asp?article_id=7572&viewcomment=1
The problem is actually both ways.
We've already discussed the issues with loop-powered I/O's and this appears to be an impossible solution to resolve with existing equipment (I'm still waiting for someone to identify the supposed version that evidently fully complies)
There are still issues even with direct connection to a control panel. If the panel has an output or outputs that operate on all the the required conditions then it shouldn't be a problem, But do most panels have these outputs for all the conditions and in the times required?
I read the info on the link you provided and I believe it to be a bit unclear about the issue of the control panel. It almost reads as if the interface device does all the monitoring of the 7273 conditions but how can it? These conditions are normally monitored by the fire alarm control panel.
I telephoned the manufacturers and their answers were all a bit confusing and included the following explanations:
a) By saying their interface monitors 12 conditions the interface is only actually looking for a single fault condition from a control panel relating to any or all of the 7273 conditions.
b) If the control panel only monitors say, 3 of the required conditions, then it is only these 3 conditions that the interface will operate to. (there was no understandable reply to how this complies with BS)
c) The requirements for BS7273 don't relate to the fire alarm system but just the doors etc. system. The fire alarm system is covered instead by BS5839.
I was somewhat confused by these answers, and said so. They have now promised to get their top man to call me sometime in the future. I'll let you know what they say, if and when it happens.
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Is the problem here that we are looking at I/O's on the fire alarm system that signals the door release that meet this,as opposed to an door closer interface that take signal's from the fire alarm?
http://www.fseonline.co.uk/articles.asp?article_id=7572&viewcomment=1
This is similar to the Salamander (except I think the Sal is better)... at the end of the day both systems are going to react on the opening or closing of a relay or relays controlled by the fire panel.
If you look at the list provided by Wiz I would think that all the faults would cause a "general fault" relay within your CIE to switch over... with the exception possibly of a software fault or the disablement of a device (quite what the power supply voltage has got to do with anything i'm not sure)
120s - Open or short circuit
3 or 60s - Reduction of power supply voltage
32m - Failure of normal supply
17m - Failure of standby supply
120s - Open or short circuit on mcp or detector circuit
120s - Removal of any mcp or detector designed to be detachable
120s - Earth fault
120s - Fuse failure
120s - Software fault
120s - Disablement
120s - Failure of radio activated systems
If your gen fault relay also switches over on software/disablement then happy days providing you run a cable from the CIE to relays within the door psu...
The problem as far as I can see is that at the moment we can't use an I/O unit on the loop to switch a door psu because it either cannot be programmed to react to all the necessary fault conditions, or won't change state in the event the loop stops transmitting data or voltage or both....
So we are back to using the panel relay (if it responds to all the conditions listed) and running more cables or using the panel relay (if it responds to all the conditions listed) and one of the radio tx systems.
.... I think.... !
David, I think you are seeing the problems exactly as I see them.
I'd be quite happy if someone proved I was misunderstanding the BS or to highlight all equipment that fully complies with the BS and how, because then it would make life much simpler for those of us who care in trying to comply with BS7273-4
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Is the problem here that we are looking at I/O's on the fire alarm system that signals the door release that meet this,as opposed to an door closer interface that take signal's from the fire alarm?
http://www.fseonline.co.uk/articles.asp?article_id=7572&viewcomment=1
The problem is actually both ways.
We've already discussed the issues with loop-powered I/O's and this appears to be an impossible solution to resolve with existing equipment (I'm still waiting for someone to identify the supposed version that evidently fully complies)
There are still issues even with direct connection to a control panel. If the panel has an output or outputs that operate on all the the required conditions then it shouldn't be a problem, But do most panels have these outputs for all the conditions and in the times required?
I read the info on the link you provided and I believe it to be a bit unclear about the issue of the control panel. It almost reads as if the interface device does all the monitoring of the 7273 conditions but how can it? These conditions are normally monitored by the fire alarm control panel.
I telephoned the manufacturers and their answers were all a bit confusing and included the following explanations:
a) By saying their interface monitors 12 conditions the interface is only actually looking for a single fault condition from a control panel relating to any or all of the 7273 conditions.
b) If the control panel only monitors say, 3 of the required conditions, then it is only these 3 conditions that the interface will operate to. (there was no understandable reply to how this complies with BS)
c) The requirements for BS7273 don't relate to the fire alarm system but just the doors etc. system. The fire alarm system is covered instead by BS5839.
I was somewhat confused by these answers, and said so. They have now promised to get their top man to call me sometime in the future. I'll let you know what they say, if and when it happens.
I read it as the door must close in the event of any of the 12 conditions (which this unit could do).
However,in the event of software failure is a bit of a sticky one unless it is a totally self intelligent processor based I/O!!
No I/O is infallible as I have had plenty that sit quite happy until called for and the actual relay fails - how do you compensate for that I ask??
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I'm going down the pub to think about it..... I'll let you know..!!
8)
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I read it as the door must close in the event of any of the 12 conditions (which this unit could do).
I haven't heard from the manufacturers yet to answer my queries but I think they are going to say that their unit monitors 1 fault relay contact in the control panel ,and they are assuming that this relay contact operates for any or all of the 12 conditions. I personally think it is hyperbole to say the unit monitors 12 conditions but that isn't really the important issue.
However,in the event of software failure is a bit of a sticky one unless it is a totally self intelligent processor based I/O!!
I think the BS says 'software failure' but not explain exactly what they mean by this or how it should be achieved.
No I/O is infallible as I have had plenty that sit quite happy until called for and the actual relay fails - how do you compensate for that I ask??
I think it is fair to say that the most likely fault with a relay is that it won't 'turn on' at the critical time so to hold it 'on' in the normal condition and turn 'off' on 'alarm' seems a sensible 'fail-safe' option. But I agree with you that nothing is infallible.
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I read it as the door must close in the event of any of the 12 conditions (which this unit could do).
I haven't heard from the manufacturers yet to answer my queries but I think they are going to say that their unit monitors 1 fault relay contact in the control panel ,and they are assuming that this relay contact operates for any or all of the 12 conditions. I personally think it is hyperbole to say the unit monitors 12 conditions but that isn't really the important issue.
However,in the event of software failure is a bit of a sticky one unless it is a totally self intelligent processor based I/O!!
I think the BS says 'software failure' but not explain exactly what they mean by this or how it should be achieved.
No I/O is infallible as I have had plenty that sit quite happy until called for and the actual relay fails - how do you compensate for that I ask??
I think it is fair to say that the most likely fault with a relay is that it won't 'turn on' at the critical time so to hold it 'on' in the normal condition and turn 'off' on 'alarm' seems a sensible 'fail-safe' option. But I agree with you that nothing is infallible.
I wasn't going to get involved in this because of the contradictions and personal perceptions but now that I have,well,I'm contradicting and arguing against myself now!!!
Polarised relay on a bell circuit anyone????
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I haven't really got time to do this but I am determined to get the confusion with BS7273-4 out in the open.
I'm not trying to score points off anyone or to make things difficult for anyone, although I am disappointed that some people who have the ability to clear this matter up seem unwilling to do so.
I'm just a simple fire alarm engineer who feels that it is not only I who is unable to understand and comply with this BS and I am just trying to sort things out for everybody's benefit.
Further to the above, I've just been reading the section regarding British Standards on the Fireco Dorgard X website at www.firecoltd.com/DGXBritishStandards.asp and have found the following:
(please note that this is only part of the full text)
BS 7273-4 concerns the interface (Critical Signal Path) between fire detection and fire alarm systems with forms of door hardware including devices to hold open self-closing fire doors.
The Critical Signal Path is the connection between the CIE and the door hardware. If the connection is compromised, the door hardware must fail-to-safe. It is important to note that for acoustically actuated systems fire alarm sounder circuits are not deemed to be part of the Critical Signal Path. There are three categories of actuation. A combination of categories can be used throughout a building according to the specific needs of the areas in question on a risk assessed basis.
I have highlighted part of the text above that confuses me and which I will discuss with Fireco when they return my call.
I would have thought that the fire alarm sounder circuits were the most important part of the csp on an acoustic system.
Can anyone else shed any light on what they mean?
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7273
3.9 critical signal path
all interconnections and communications between fire alarm CIE and
the input terminals on, or within, (a) device(s) provided to open, release
or unlock a door or shutter, or between CIE and other control
equipment by which such devices are controlled
NOTE 1 Examples of other control equipment include the
control equipment of an access control system.
NOTE 2 In the case of acoustically actuated systems (see Clause 16),
fire alarm sounder circuits are not considered to be part of the critical signal path.
Does seem a bit strange to me.... except that these "acoustic" units can't be used on Cat A doors, so the "fail safe" requirements are far less onerous....
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7273
3.9 critical signal path
all interconnections and communications between fire alarm CIE and
the input terminals on, or within, (a) device(s) provided to open, release
or unlock a door or shutter, or between CIE and other control
equipment by which such devices are controlled
NOTE 1 Examples of other control equipment include the
control equipment of an access control system.
NOTE 2 In the case of acoustically actuated systems (see Clause 16),
fire alarm sounder circuits are not considered to be part of the critical signal path.
Does seem a bit strange to me.... except that these "acoustic" units can't be used on Cat A doors, so the "fail safe" requirements are far less onerous....
Thanks David.
Comments:
(1) Obviously the definition of csp in 7273-4 is different to that in BS5839-1 although the concept of it is similar. Pity they didn't use a new term in 7273-4. I can see it confusing people.
(2) I would have thought that in any Category system, if the sounders didn't operate then the acoustic devices wouldn't operate, and so the integrity of sounder circuits is pretty critical!
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There you go again Wiz, using common sense, when will you see the light???
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I still hadn't heard from Fireco but I gave them a call a few minutes ago.
The guy I spoke to said that he wasn't technical enough to answer all of my questions but I understood from him that there is one fault input from the cie into their TX and that the panel needs to generate any of the required fault conditions to be able to signal their unit. Obviously if the control panel could only generate some of the fault conditions then only these could be sent to operate the TX. It would therefore appear that the TX itself doesn't actually monitor for all the fire system BS required conditions itself, as such (not that I'm saying it should) although the text on the link provided by Buzz earlier could be read as if it does.
The guy wasn't able to confirm any specific fire alarm control panels that were tested with their TX and that also definitely produced all the required 7273-4 fault warnings, although he said that someone more technical than him in his organisation might know of something and might call me back.
It sounds like the System X product is not the total solution to the queries being raised in this thread despite Buzz's previous highlight of a link to it hoping it would be.
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So to recap, as we kind of thought, the fireco or the Salamander product just want a relay from the fire panel to switch to cause the transmitter to signal the doors to release...
So now we need a panel that either has a relay that will switch over under all conditions (not forgetting this applies to non addressable micro processor controlled panels as well) or an I/O that will switch over under all conditions.
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So to recap, as we kind of thought, the fireco or the Salamander product just want a relay from the fire panel to switch to cause the transmitter to signal the doors to release...
So now we need a panel that either has a relay that will switch over under all conditions (not forgetting this applies to non addressable micro processor controlled panels as well) or an I/O that will switch over under all conditions.
David, I basically agree with that recap. Of course, it doesn't have to be a single relay and a combination of different relays would still work. I think that they would all have to be NC with the relay powered on in it's 'normal' state. I assume products like the Salamander and System X are looking for a NC input opening on 'alarm/fault'
I going to email a lot of the panel manufacturers and ask if any of them have anything in their ranges that they say definitely complies with BS7273-4
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i,m fairly sure that all the above fault conditions would trigger the fault contact in the a'a panels we use (Advanced).
The fault relay in the panel is inverted to fail safe. I did a hotel two years ago with the supply to the door holders going through the panels fault and fire contacts and it did close the doors on the fault conditions i generated during commsioning.
They had a small leak last week and water got into a detector and all the doors shut when it showed up earth fault on the panel.
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Not sure about fireco. but salamander has two inputs one for fire and one for fault... both inputs cause all the doors to close.
The inputs work when 24volts is applied, so the fire contact needs to be open, and the fault contact needs to be closed in "normal" state.
Sounds like "Advanced" may be the kiddy Graeme... just depends on this "software" failure bit, and if an I/O unit can react the same to save running more cables...
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Graeme & David, thanks for info regarding the Advanced. Although we really need a bit more confirmation than just 'fairly sure'. :)
It has begun to worry me that none of the fire alarm panel manufacturers who can comply with the recommendations of BS7273-4, are not highlighting such in their literature. Is it because they can't? or is it because this issue hasn't become a big enough issue in their eyes yet? I'm hoping that what we are posting here might bring answers to these questions.
If we find panels with all the required fault outputs then that solves the issues for 7273-4 where interfacing is carried out at the panel.
I think that addressable loop outputs will be a bigger problem. As explained previously, not only will their relays have to be powered in the 'normal condition but I think they have to be able to respond to two other criteria:
a) To respond to a data signal or signals relating to any of the system faults required by the BS (may be possible through c&e in some software) and to a fire signal.
b) Loss of data signals
The first is probably easy to achieve.
I can only see the second being achieved by a method where the addressable interface is made so that it is expecting to see a regular 'O.K.?' data signal and operating whenever it can no longer see it.
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Not sure about fireco. but salamander has two inputs one for fire and one for fault... both inputs cause all the doors to close.
The inputs work when 24volts is applied, so the fire contact needs to be open, and the fault contact needs to be closed in "normal" state.
Sounds like "Advanced" may be the kiddy Graeme... just depends on this "software" failure bit, and if an I/O unit can react the same to save running more cables...
David, Is the bit I've highlighted above in accordance with BS?
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Yes, I can't see anyreason why not.
Clause 10 note.
For Category A actuation, it is unlikely that a system that relies on operation of one or more relays to actuate a release mechanism will
conform to 5.1.1e) unless the coil of at least one relay is normally energized; in the case of a normally de-energized coil, failure of both the
normal and standby power supply to the fire detection and fire alarm system precludes changeover of the relay contacts in the event of fire.
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Yes, I can't see anyreason why not.
Clause 10 note.
For Category A actuation, it is unlikely that a system that relies on operation of one or more relays to actuate a release mechanism will
conform to 5.1.1e) unless the coil of at least one relay is normally energized; in the case of a normally de-energized coil, failure of both the
normal and standby power supply to the fire detection and fire alarm system precludes changeover of the relay contacts in the event of fire.
For years people have been saying that all relays used in this sort of interface must be powered on in the 'normal' state because failure of any normally 'unenergised' coil means that the system is not fail-safe.
I personally have always thought this to be overkill but believed that this requirement was now incorporated in this standard (as I've always said I don't profess to understand it all). But I agree the text you highlight could be read that it is not. But I am confused by the text you have highlighted. It doesn't make 100% sense to me. What do others think?
The drawing attachment shows both relays as NC contacts (and not a NO as you said one particular product needed!) The fire relay contacts are described as 'normally closed' and the fault relay contacts are described as 'held closed' so i read this as being that the 'fault' relay at least is 'normally energised'. I wonder why they consider the fault relay to be more important than the fire relay? I would have thought that the fire condition is always important and that very few fault conditions would have much as much impact.
As I've always said, this BS is very confusing.
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I have this morning emailed 5 major panel manufacturers regarding their equipment's compliance with BS7273-4.
Only one has got back so far and have confirmed that they need to look into BS7273-4 before they can comment.
I get the feeling that the industry has not paid too much attention to this BS yet.
I'll keep you advised of progress
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I have this morning emailed 5 major panel manufacturers regarding their equipment's compliance with BS7273-4.
Only one has got back so far and have confirmed that they need to look into BS7273-4 before they can comment.
I get the feeling that the industry has not paid too much attention to this BS yet.
I'll keep you advised of progress
When you say "I get the feeling that the industry has not paid too much attention to this BS yet" I assume you mean the British Standard??
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I have this morning emailed 5 major panel manufacturers regarding their equipment's compliance with BS7273-4.
Only one has got back so far and have confirmed that they need to look into BS7273-4 before they can comment.
I get the feeling that the industry has not paid too much attention to this BS yet.
I'll keep you advised of progress
When you say "I get the feeling that the industry has not paid too much attention to this BS yet" I assume you mean the British Standard??
When I said the industry I meant the fire alarm control panel manufacturers
When I said this BS I meant BS7273-4 2007
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Just spoke to another well known control panel manufacturer and they said their panel didn't have all the outputs needed to comply with 7273-4 on at least the 'disablement' monitoring.
He also said that he couldn't see any manufacturers who have built a panel to the requirements of EN54 and paid to have it third-party certificated, starting all other again. It would be too expensive for them.
He also said that he would be very surprised if there was any panel currently available that would be fully compliant for use with BS7273-4 systems.
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Further to David's earlier post I have now read the BS a number of times and would comment further.
David highlighted what he called a 'note' to Clause 10. I found it within the 'commentary' to Clause 10.
I think that what it is saying is that because it is unlikely that all relays used in the interface method are likely to be used in their energised state, if at least one is normally energised, this should be sufficient.
It further mentions Clause 5.1.1.e which is a recommendation that if both the normal and standby supplies to any part of the fire detection and alarm system on which the 'door release/holds' mechanism depends for it's correct operation then the system 'fails safe' within 120s.
Obviously, if the interface relays were in the control panel and this lost both normal and standby supplies any relay's it was holding energised would de-energise, and so if this relay was part of the signalling circuit to the door releases/holds then that circuit would fail-safe.
Makes sense to me. If the above was what David was explaining, I apologise for not understand fully the first time.
Obviously if there are other 'applicable' power supplies elsewhere on the system these would also have to be taken into consideration.
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If people actually bought the standard and read its contents as professional engineers, some of the mystery would go away, rather than lots of I think my brother in law once met a man in a pub and he said his cousin bought a copy and it said........... For example it does NOT make any vague references to software faults. It is quite specific, it is the software fault that must be monitored (and hence give a fault warning) for compliance with the EN on control panels. It happens anyway, so dont fret. Similarly, if anyone understood the first thing about control panel design, it would be obvious that the list of faults that people find so daunting and ridiculous is simply the list of faults that must be monitored and hence give a fault warning for compliance with the EN. We did this to stop people fretting about whether the faults are actually monitored or not. If they arent the panel doesnt meet BS 5839-1/BS EN 54-2. We mistakenly thought that people knew enough about the panels they were installing to recognize that list and so move on to read stuff they do need to worry about.
Instead of worrying about how hard it makes life, think about fire safety and worry about the people who can be trapped in a burning building with doors that wont open, because there is a fault on the fire alarm system or staircases that are full of smoke because doors dont close because there is a fault on the fire alarm system. It never ceases to cause a wry smile that enforcers who worry about rubbish like the number of hinges on a fire door simply because that it easy to count, assuming that enforcers can count to 3 with some accuracy, choose to ignore a standard that relates to circumstances in which a man died in horrific circumstances in which he could not be reached because the electronically locked doors did not release (cos supposedly it was all too much like hard work to make the interface fail safe) simply because its too hard to understand.
As it happens, I have to have an annual procedure by a leading specialist to prevent me getting a fatal illness. I believe the subject is quite hard to understand, but I am glad the good Prof has taken the trouble to do so, rather than treat my ingrowing toenails, which is probably a lot easier. Equally, last time I saw him in the street he was getting into a Porche with a nice bit of stuff, so I assume that doing difficult things pays better than doing toenails.
As for acoustically operated devices, again there is no need to fret if you cant understand why a sounder circuit is not part of the critical path in the case of these devices. Sheesh, its only a definition for pitys sake. If it really matters to anyone its a conceptual point that is clear as day if you think about it. Cat B must fail safe if the critical signal path fails. Now think about how an acoustic device works. Bells go ding a ling a ling doors close, kerchink. If the sounder circuit has failed how will the ding a ling noise be made??????? Pretty clever that would be. So if the definition of critical signal path included sounder circuits, it would be IMPOSSIBLE ever again to use an acoustically operated device. Old Uncle Neil of Dorgard would find the closure of his company something of a pity, and those made redundant because of careless or imprecise drafting of a definition would find it mildly inconvenient; why would one want to stop acoustically operated devices, given that BS 7273-4 recommends agaisnt their use in specificed mega crticial situations.
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Further to my earlier posts regarding the Fireco System X for use in Category A systems which Buzz highlighted as something that could possibly answer all of our questions, I would confirm that I have been in contact with them and established that their product monitors for a 'fault' and 'fire' condition from relay contacts. It does not within itself directly monitor all the individually listed fault conditions listed in BS7273-4 it monitors a set of fault relay contacts.
There is obviously nothing wrong with this, of course, and is what I would have expected such an interface of being capable of doing. The interface would need to be connected to a fire alarm control panel that monitored all of the BS7273-4 5.1.1. fault conditions and gave a fault output.
When I asked them if they knew of a control panel that complied with all of they 'fault conditions' they replied "no. do you?"
I want to make it clear that Fireco have been most helpful in my quest to clear up the confusion created by Buzz's suggestion, and I am sure that their product is an excellent product and is perfectly suited for the role it has been designed to provide.
For those who have not read my post in reply to C.T. I would also confirm that I have contacted 5 panel manufacturers regarding their equipment's ability to be able to interface fully with a 7273-4. Two have replied. I am still awaiting reply from the other three. The two that have replied thought that their equipment could not meet all the recommendations by at least one requirement.
Strangely, they both made the point that as BS7273-4 was an 'installation standard' rather than an 'equipment standard', they had not paid much attention to it!
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Well Colin, thank you for taking the time to explain things so clearly and concisely to all of us mere ignorant fire alarm engineers.
I would reply to some of your comments as follows:
1) It is precisely those people who have read a copy of 7273-4 that are complaining that it is difficult to understand. Not those who have only heard rumours about it. I also think it is unfair to infer that I am not 'professional' because I don't understand it and can't unravel all it's mysteries even after reading it many times. I normally have very few problems understanding these sort of documents. Furthermore, I can't recollect one person posting on this forum, apart from yourself, that claims that 7273-4 is straightforward and simple to understand!
2) You continually go on about the need for the Standard. I can't remember anyone (and certainly not myself) arguing against this need. Your emotive descriptions of people being trapped in a burning building are therefore superfluous.
3) If, as you say, the monitoring of software faults and indeed all the other long list of fault monitoring requirements, is automatically met by any panel meeting BS 5839-1 (is this the right BS?)/EN 54-2 then why bother listing all of these requiremnts in BS7272-4? Why not just, or alternatively also, state in BS7273-4 that this is so. I am afraid that, despite your beliefs that they should, very few fire alarm engineers learn all the BS recommendations for the requirements intrinisic in manufacturing a control panel. This is normally the job of the panel designer. Those of us that 'fret' about the specifics of BSs are those who are trying to make them work.
4) I have recently contacted 5 well-known control panel manufacturers regarding this standard. Two have already replied. Both said that BS7273-4 is an 'installation standard' and therefore they have not read it and are not that interested in it.
I asked them both, if any equipment in their range met all the recommendations of BS Clause 5.1.1. Both said that they 'thought they probably did' apart from the recommendation for monitoring disablements. Therefore neither, despite your assertions, that any fully BS compliant panel available today would meet the BS7273-4 interfacing recommendations, these two appear not to.. At the very least, a disablement on their control panels did not provide a signal that could be used to interface into a BS7273-4 system.
The other three well known panel manufacturers have not yet replied. I wonder why not? I would have thought that if they had a panel that was fully suitable for use with BS7273-4 they would be shouting it from the rooftops.
5) I still do not understand your explanation of my previous comments regarding the critical signal path comment. I appreciate that it is probaly just me who is too stupid to understand it and I will refer to BS7273-4 to try to rectify my ignorance. Alternatively, I await explanation from other members of Firenet.
6) I have previously asked you to identify the addressable loop powered interface that could be used in BS7273-4 systems that I understood you claimed was currently available. Are you yet able to do so for the benefit of all us ignorant fire alarm engineers who are desperately trying to work out what it could be? Again, I'm surprised that it's manufacturers are keeping it so secret.
If you find any of the above to be be written in a sarcastic tone, I can only offer the playground defence of 'well you started it' ;)
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Well obviously I'll join you in the thick as a McDonalds Milkshake Club Wiz....
So regarding this critical path and sounders on acoustic operated systems then....
11.3 If any part of the critical signal path is not exclusive to the release mechanisms (e.g. part of a loop of an addressable fire detection and fire alarm system), that part of the critical signal path should be protected against a single cable fault (i.e. both short circuit and open
circuit) anywhere on that part of the critical signal path (e.g. by the provision of short circuit isolators).
So an analogue addressable loop can be part of the CSP but standard sounder circuits aren't then?
11.4 In the case of acoustic actuation, failure of any single fire alarm sounder should not prevent the actuation of release mechanisms for self-closing fire doors at more than one location at which the doors protect stairways that form means of escape in the event of fire.
But the sounder circuit is not deemed part of the CSP and is allowed to fail..... ?
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Wizzy,
1.Read other people's postings and you will find that some clearly have not bought the standard and rely on rumours as to what it says.
2. Bearing in mind that at least one poster says he totally ignores it, I assume he does not see the need for it. Others argue against its recommendations because they are preceived to be a nuisance. So, i assume they dont see the need for these recs. I do not think that the findings of the fatal accident enquiry were particularly emotive.
3. Because some older panels might not meet the BS EN, and you would want to be careful then. Moreover, we did not want people to have to buy the BS EN in order to find out whether they did, because (I know you wont believe this) some people moan like nothing on earth about having to buy a standard.
4. BS 7273-4 is a code of practice and hence in simple parlance IS an installation standard. It is NOT a product standard.
5. I am well aware that the diablement facility is the most tricky. Ask your panel chums why they cant give you an output when there is disablement. I can't help it that it's not a good idea to leave fire doors standing open while the detectors that are meant to release them are disabled.
6. I cannot make the definition any clearer. It was included to satisfy an issue raised by the trade association as a result of (valid) concern by one of their members. Both the association and the member were entirely happy, so I assume they understood it.
7. Company policy is not to advertise or promote any particular product.
Davie, I do not know what you mean by allowed to fail. If the sounder circuit fails, how CAN an acoustically operated device be triggered?????? I am clearly missing why people find that a difficult concept to grasp, but I cannot think of how to make it any clearer. No ding a ling, no close doors. Does that help.
Sounder circuits are monitored, whereas sounders are not. People might feel mildly aggrieved (or so we thought, but then we could be wrong) if they were trapped in a burning building (it's that darn burning building again, Wiz, but if you didnt get them we would all be out of business) because TWO staircases were BOTH impassable because a single bell on just one floor was not working and so doors did not close (i.e. no ding a ling).
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Wizzy,
1.Read other people's postings and you will find that some clearly have not bought the standard and rely on rumours as to what it says.
2. Bearing in mind that at least one poster says he totally ignores it, I assume he does not see the need for it. Others argue against its recommendations because they are preceived to be a nuisance. So, i assume they dont see the need for these recs. I do not think that the findings of the fatal accident enquiry were particularly emotive.
3. Because some older panels might not meet the BS EN, and you would want to be careful then. Moreover, we did not want people to have to buy the BS EN in order to find out whether they did, because (I know you wont believe this) some people moan like nothing on earth about having to buy a standard.
4. BS 7273-4 is a code of practice and hence in simple parlance IS an installation standard. It is NOT a product standard.
5. I am well aware that the diablement facility is the most tricky. Ask your panel chums why they cant give you an output when there is disablement. I can't help it that it's not a good idea to leave fire doors standing open while the detectors that are meant to release them are disabled.
6. I cannot make the definition any clearer. It was included to satisfy an issue raised by the trade association as a result of (valid) concern by one of their members. Both the association and the member were entirely happy, so I assume they understood it.
7. Company policy is not to advertise or promote any particular product.
Davie, I do not know what you mean by allowed to fail. If the sounder circuit fails, how CAN an acoustically operated device be triggered?????? I am clearly missing why people find that a difficult concept to grasp, but I cannot think of how to make it any clearer. No ding a ling, no close doors. Does that help.
Sounder circuits are monitored, whereas sounders are not. People might feel mildly aggrieved (or so we thought, but then we could be wrong) if they were trapped in a burning building (it's that darn burning building again, Wiz, but if you didnt get them we would all be out of business) because TWO staircases were BOTH impassable because a single bell on just one floor was not working and so doors did not close (i.e. no ding a ling).
Colin, thank you for your considered reply.
Because you have taken the time to answer my post in full, I feel it only right to extend you the same courtesy (using your numbering scheme)
1) Fair point.
2) Fair point.
3) Fair point, but it would have been nice to have an explanation in 7273-4 that the recommendations would/should be met by a panel meeting BS5839/EN 54. (subject to 5) below).
4) Understood. The panel manufacturers are obviously not yet taking into account BS7273-4 although they obviously take into account that other 'installation standard'; BS5839-1 because they often describe their equipment as 'designed for use in systems complying with BS5839-1'
5) I consider it somewhat confusing to be told that 'up to date' panels should be able to monitor all the 7273-1 5.1.1 recommendations when they clearly don't on. at least, the 'disablement' recommendation. I've asked representatives (hardly my chums!) of panel manufacturers about this and they say they don't need to, to comply with current 'product standards'
6) I need to find time to read about this a bit more, to make sure I understand it, before making any further comments.
7) Understood and reasons why accepted. But can't you give us even a cryptic clue to point us in the right direction? ;)
I would once again state that I have no ulterior motive in 'highlighting' BS7273-4. I am hoping that my humble efforts in discussing the 'problems/confusion' with it on this forum, may even lead to some better attention to 7273-4 by everybody who should be working with it.
I'm sure that everyone who worked on BS7273-4 did so with the best intentions, and I also accept that if I was involved in producing something like it, I would be most likely to want to 'support' it.
I appreciate that this particular forum gives many of us the unique opportunity to discuss things with people deeply involved in producing BSs' and I would hope that these people understand that most of the criticism is surely meant to be constructive.
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Wizzo,
1. Thank you.
2. Thank you. On this point, I have some sympathy with the fire alarm guys who are doing their best to comply and who actually care. I dont have a lot of time for fire safety generalists, who are arrogant enough to say that because a subject is too complicated for them, they will just ignore the recommendations of a code that all parties, including CLG and CFOA, agreed was definitely needed on the grounds of safety. If the world we live in has become too complicated because its not all bimetallic strips and hinges on fire doors that non engineers can understand, would it not be best to stop counting hinges and do something else for a living.
3. You will find these things in BS 5839-1 for exactly the same reason, so people dont have to buy too many standards. You dont seem to have a problem with BS 5839-1, which has more or less the same list and does not say not to worry about it cos its all in the EN.
4. The panel manufacturers will wake up one day when it all goes pear shaped and they have to explain that like some of the posters, they were above bothering about a national consensus standard published by the UK's national standards body , and supported by CLG, CFOA and even London Fire Brigade, the greatest fire brigade in the whole of.................London.
5. Disablement is an issue but hopefully you see our concern over people disabling detectors without realising the knock on effects. One reason to disable is during hot work. During hot work fires sometimes occur. Thats not the time to find your fire doors didnt close.
6. If its not clear (and I cannot understand why it wouldnt be), trust me it does not matter to you. It is a minor subtlety to avoid inadvertently saying that acoustically linked devices are not permitted when in fact they are.
7. No.
Maybe we should re-start the seminars we did on BS 7273-4. I still feel its taking money for nothing as the code is easy peasy, but why look a gift horse in the mouth.
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Davie, I do not know what you mean by allowed to fail. If the sounder circuit fails, how CAN an acoustically operated device be triggered?????? I am clearly missing why people find that a difficult concept to grasp, but I cannot think of how to make it any clearer. No ding a ling, no close doors. Does that help.
Sounder circuits are monitored, whereas sounders are not. People might feel mildly aggrieved (or so we thought, but then we could be wrong) if they were trapped in a burning building (it's that darn burning building again, Wiz, but if you didnt get them we would all be out of business) because TWO staircases were BOTH impassable because a single bell on just one floor was not working and so doors did not close (i.e. no ding a ling).
To be honest I think I must be missing the point.
I don't understand why an analogue addressable loop, which is part of the critical signal path (11.3) .....
"11.3 If any part of the critical signal path is not exclusive to the release
mechanisms (e.g. part of a loop of an addressable fire detection and
fire alarm system).............."
...can be allowed to fail, therefore not operating its loop sounders....(no ding-a-ling), therfore not providing an acoustic signal (ding-a-ling) to activate the release mechanism on a Cat B door.
But.....
11.4 In the case of acoustic actuation, failure of any single fire alarm sounder should not prevent the actuation of release mechanisms for self-closing fire doors at more than one location at which the doors protect stairways that form means of escape in the event of fire.
So does this mean that there should be two alarm sounders in the vicinity of each acoustically operated door mechanism in order that the door will still release even if one sounder fails ?
And just generally, why is it acceptable for acoustically controlled doors not to close if sounders fail as you seem to intimate ?
"I do not know what you mean by allowed to fail. If the sounder circuit fails, how CAN an acoustically operated device be triggered?????? I am clearly missing why people find that a difficult concept to grasp...."
Well this is what i don't grasp... your major concern over these people trapped in a burning building... doors need to shut if the door is classed Cat A (by definition a hardwired/radio system) but can stay open if its a Cat B door (could be hardwired/radio/acoustic)
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On the whole software thing - what section mentions data signals?
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Surely data signals are part of the software as such?
The way I see it, is that to comply with BS7273-4 for Cat A systems using a loop-powered interface you would need
i) To have the interface relay loop-powered and normally energised
ii) For it to de-energise to the appropriate fault conditions elsewhere on the system, it would need to receive the appropriate data telling it to de-energise. But that is the problem. What if the data doesn't get through because of any sort of other fault stopping it?
I believe that it would need to work with the loop interface being sent regular 'o.k.' signals but if these should stop for any reason the relay would de-energise.
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Further to my earlier posts regarding suitable fire panels for use with BS7273-4 systems.
Two of the 5 manufacturers contacted felt their panels were not suitable due to lack of having a 'disablement' relay.
Two of the five have not yet responded. They could be still looking into the matter because they hadn't yet given BS7273-4 any thought. Or they could be showing their disdain of BS7273-4 because it is only an 'installation standard'.
Ampac have responded and confirmed that their FireFinder range has both a Fault and Disablement relay that they believe could be used for interfacing to a BS7273-4 installation. They are now giving the matter further consideration.
Ampac's techinical guy is also considering ways of using their configuration programme and current Apollo interfaces to provide a loop-powered interface for BS7273-4 systems. He thinks he can make it work!
I hope CT doesn't say this was the manufacturer he knew about!
I'll keep you informed of any further developments.
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Surely data signals are part of the software as such?
The way I see it, is that to comply with BS7273-4 for Cat A systems using a loop-powered interface you would need
i) To have the interface relay loop-powered and normally energised
ii) For it to de-energise to the appropriate fault conditions elsewhere on the system, it would need to receive the appropriate data telling it to de-energise. But that is the problem. What if the data doesn't get through because of any sort of other fault stopping it?
I believe that it would need to work with the loop interface being sent regular 'o.k.' signals but if these should stop for any reason the relay would de-energise.
I read it as the generation of a fault due to software failure as already monitored by panels that have to comply to part 4 (internal watchdog etc. that monitors the software or config).It doesn't mention data.
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Ampac have responded and confirmed that their FireFinder range has both a Fault and Disablement relay that they believe could be used for interfacing to a BS7273-4 installation. They are now giving the matter further consideration.
I hope CT doesn't say this was the manufacturer he knew about!
I'll keep you informed of any further developments.
Just for info... the Syncro "Alarm Contact" will change state on any disablement if not used elsewhere in c&e ... so presently I still think the only way of complying is not to use loop powered I/Os and run a separate cable between CIE and door PSUs..... less anyone knows different??
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Surely data signals are part of the software as such?
The way I see it, is that to comply with BS7273-4 for Cat A systems using a loop-powered interface you would need
i) To have the interface relay loop-powered and normally energised
ii) For it to de-energise to the appropriate fault conditions elsewhere on the system, it would need to receive the appropriate data telling it to de-energise. But that is the problem. What if the data doesn't get through because of any sort of other fault stopping it?
I believe that it would need to work with the loop interface being sent regular 'o.k.' signals but if these should stop for any reason the relay would de-energise.
I read it as the generation of a fault due to software failure as already monitored by panels that have to comply to part 4 (internal watchdog etc. that monitors the software or config).It doesn't mention data.
Buzz, what you say sounds absolutely right. But do you think that by not mentioning the word data it means they are not worried about loss of data? If so, that would be great for us who are struggling to comply.
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Well,no one seemed too worried about data loss when complying to the "tick boxes" for CIE in complying to part 4 prior to 7273 in reference to the software part,and as it appears that to comply to 7273 means compliance to other standards amongst other things then I take it as it is written - no point complicating what may be already complicated in my opinion!
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Wouldn't that be a bit of a hole in the standard then.... surely if there is a state when no data can be sent to an I/O to tell it to change state then the doors should release ?
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Theres holes in all of them if you stop and think about them - if it was amended to include loss of data then (and has already been suggested/stated) there would be a major diffoculty for using any manufacturers equipment as it sits presently (they aren't going to make a special issue panel for the UK that is going to cost more than a few tweaks within software or materials).
If it meets the recommendations of Part 4 1988 (although no time limits are given for the generation of faults within this version) then it ticks the boxes for this.
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So what we really need then is guidance from the NSI committee to know for sure if they mean the loss of ability to transmit data or something different as it has major impact on the implementation of this standard....
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So what we really need then is guidance from the NSI committee to know for sure if they mean the loss of ability to transmit data or something different as it has major impact on the implementation of this standard....
If you have a gander at the standards for CIE (EN54-2 or 5839-4 1988) they list what needs to generate a fault in relation to software controlled systems.All panels that state compliance to these standards meet the requirements for 7273 (imo) because it cross references from other standards.
There may be a case to look at the implications of software failure but I think that relates to a far bigger picture than the operation and integrity of door closers,and brings into question the standards referiing to CIE and the realistic chance of current manufacturers making such UK specific CIE to comply.
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David you are right to be concerned about this matter. I personally feel that all the efforts to make the system as 'fail-safe' as possible are wasted through not requiring some method for monitoring that the data is getting through correctly.
However, Buzz is right if his interpretation of a 'software' fault doesn't include loss of loop data (and I think he is right). I think his belief that this is not included in recommendations because it is impossible to do with existing equipment is also correct.
If BS, in their wisdom, say that we don't have to correct monitor data loss who are we to argue? It saves us another trying to resolve another difficulty.
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Davie, I do not know what you mean by allowed to fail. If the sounder circuit fails, how CAN an acoustically operated device be triggered?????? I am clearly missing why people find that a difficult concept to grasp, but I cannot think of how to make it any clearer. No ding a ling, no close doors. Does that help.
Sounder circuits are monitored, whereas sounders are not. People might feel mildly aggrieved (or so we thought, but then we could be wrong) if they were trapped in a burning building (it's that darn burning building again, Wiz, but if you didnt get them we would all be out of business) because TWO staircases were BOTH impassable because a single bell on just one floor was not working and so doors did not close (i.e. no ding a ling).
To be honest I think I must be missing the point.
I don't understand why an analogue addressable loop, which is part of the critical signal path (11.3) .....
"11.3 If any part of the critical signal path is not exclusive to the release
mechanisms (e.g. part of a loop of an addressable fire detection and
fire alarm system).............."
...can be allowed to fail, therefore not operating its loop sounders....(no ding-a-ling), therfore not providing an acoustic signal (ding-a-ling) to activate the release mechanism on a Cat B door.
But.....
11.4 In the case of acoustic actuation, failure of any single fire alarm sounder should not prevent the actuation of release mechanisms for self-closing fire doors at more than one location at which the doors protect stairways that form means of escape in the event of fire.
So does this mean that there should be two alarm sounders in the vicinity of each acoustically operated door mechanism in order that the door will still release even if one sounder fails ?
And just generally, why is it acceptable for acoustically controlled doors not to close if sounders fail as you seem to intimate ?
"I do not know what you mean by allowed to fail. If the sounder circuit fails, how CAN an acoustically operated device be triggered?????? I am clearly missing why people find that a difficult concept to grasp...."
Well this is what i don't grasp... your major concern over these people trapped in a burning building... doors need to shut if the door is classed Cat A (by definition a hardwired/radio system) but can stay open if its a Cat B door (could be hardwired/radio/acoustic)
David, my 'take' on understanding this; The actual sounders themselves are not monitored for failure even in BS5839-1. Furthermore, 'acoustically' operated door holds can't be used anyway in the most 'critical' categories of system. The liklihood of a single sounder failing is pretty small, but in acoustic systems the most critical doors need to be covered by two sounders anyway.
Also, by my understanding, the csp of the 7273-4 installation is a different element than the csp of a BS5839-1 installation.
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Well according to Table A2 Cat A/B/C can be applied to the following type of doors at least...
4. Forming part of the enclosures of a stairway that forms part of means of escape (other than stairways described in items 2 and 3 and
stairways in dwellings) A, B or C In the case of Category C, only if the critical signal path, and any wiring from non-fire alarm control equipment to the release mechanisms, fails safe.
5. Forming part of the enclosures of a fire-resisting lobby to stairways described in items 2 to 4 inclusive A, B or C In the case of Category C, only if the critical signal path, and any wiring from non-fire alarm control equipment to the release mechanisms, fails safe.
6. Subdividing corridors A, B or C
7. Any fire door in a dwelling, other than in the common parts of an HMO A, B or C
8. Any other positions, including (but not limited to) fire doors to rooms A, B or C
.........and the following type of building
1. Common places of work, not generally occupied by significant numbers of members of the public (e.g. offices, factories and warehouses), where staff are trained in the fire safety provisions in the building A, B or C
..........So to me it seems that Acoustic units could be used on quite critical doors protecting employees and the public alike and as you say, suddenly the release mechanism needs to be in range of two sounders !
I'd lay odds 99% of dorguards installed in the country aren't within earshot of two sounders. Perhaps we should contact them and ask why they don't mention it in their installation instructions ?
Suddenly the cost saving device might not be so appealing.....!
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I think that the Dorgard is a device (liked or loathed) that was designed with current equipment in mind (ie - loop powered sounder bases etc. throughout the loop) and not the applications that they are commonly used in because of the ease in installing in existing sites (sheltered acc. nursing homes etc.) that have 20 - 30 year old Tann Sync Firecheck panels and one bell in each corridor!
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Exactly that........... So who's going to tell the owners they either need to upgrade their complete fire system and add more sounders if they want to keep the DGs or replace them with hard wired units....?!!
I think if this Standard was written before any acoustic product was on the market then acoustic products wouldn't be acceptable in a modern building...... ;)
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I suppose it's not really Dorgards (or whoever) fault or problem as they make it clear of whats required to activate it.The problem aries when the PAT guy is asked about who can they close the doors automatically because the nasty fire alarm company say it's going to cost a bomb to achieve this -
"They're chancing their arm - I can install handy units with no wiring at each door for £XXX pounds,no problem".Customer asks you why you didn't recommend these and no matter what you say they think you are trying to rip them off!
If you have the scenario that one sounder is meant to close two doors and te first door closes before the other you get dB drop off!!!
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David, your interpretation of critical is as anomalous as your interpretation of the written word. The most critical doors need cat A. I regret the fact that, as a fire alarm specialist, you think those with expertise on means of escape are wrong in their interpretation of what is critical, but the concept of criticality espoused in the table to which you refer is a well established one, in which staircases in sleeping risks and single staircase situations are more critical than cross corridor doors in a office. This is fairly basic baby talk in fire safety principles.
And you have not read what you wrote again. Nowhere does it say every acoustically linked device must receive the appropriate SPL from 2 sounders. If, however, there were acoustically linked hold open devices on two staircases that were not separated by fire doors then the two could not rely on a single bell. Is this really really very difficult to understand, because, to me, it is what you wrote correctly and then apparently misinterpreted what you wrote down.
Remember that burning building again (sorry wiz but you do somethimes get burning buildings). Bad, bad bad, very very very bad karma if people are trapped and unable to use TWO alternative staircases (which might be the only two means of escape from several upper floors), because just one tiny wee bell failed. That is what you wrote down accurately. Now believe it, or just trust loads of people who do.
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...............Remember that burning building again (sorry wiz but you do somethimes get burning buildings).
Oh Colin, you really are a one! I shook with mirth again!
I don't know where you got it into your head that I don't seem to realise that 'you do somethimes (sic) get burning buildings'.
I do look forward to you confirming where you got this little gem from! Your continual repeating of it must mean it is based on fact.
I believe that you have the wrong end of the stick, but I will gladly continue laughing along with you over my stupidity if you can just point me in the right direction of where I made this faux pas. You see, I think I understand that you sometimes get burning buildings because I've seen the pictures and read the reports. In fact, burning buildings are often uppermost in mind having been in the fire alarm system industry for 30 years.
However, I do feel that you have been somewhat kind to me in comparison to my friend David. I think that David is strong enough to fight his own battles, so I'll leave him to it for now.
But it is obvious to me, that David, like myself and others on this forum, look to our 'betters' for a bit of explanation and guidance on some matters and it is a shame that it is often given with a hefty dose of sarcasm in respect of our inadequacies.
I can assure you that we are all only trying to understand something that we obviously find difficult. In fact we are the ones that are trying to make BSs work. In that context we are, in fact, their biggest supporters.
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Wizzy, I had no idea people were simply seeking advice on things they found too difficult to understand. Now I see things much more clearly..... I was previously misled by comments such as (and I quote):
waste of paper
hands up, I didnt buy it
burn it. best thing you can do with it
men in black overcooked it
and the best one of all (from an ex enforcer) I ignore it completely.
Had I realised that all this somewhat puerile ranting was simply a request to understand a standard that is a bit tricky for non fire alarm engineers (and, yes maybe for some engineers), I would have tried to help. However, from the comments as I re-read them all today, I think many of those are beyond help, particularly those outside the fire alarm industry who cant be bothered buying it, or who think they are so much above it that they ignore it. (As a matter of record, I dont think you fit into these categories, but are merely frustrated that you cant understand some of the philosophy and practice. I can relate to this as I find the same problem in using a video recorder and, on the basis that I find "The simple guide to brain surgery" is somewhat dificult to understand, and I am not in the field of brain surgery anyway, I tend to ignore it completely too).
Clearly, your conceptual and practical, but I suspect genuine, difficulties with the standard cannot be resolved by a few simplistic words of advice here, nor are they assisted by people who dont understand the technology in the first place jumping on the bandwaggon.
Accordingly, I am pleased to offer the Wizzy fire alarm co unlimited a course on the standard at a specially discounted rate. This is a course that has been presented as a public course for some time, but it is now formally available to the Wizzyco as an in-house course. The good news is that the whole course only takes half a day as the standard is so simple. The bad news is that, even at the discounted rate, it is quite expensive, but will repay itself in the time you could have been fixing wee alarm systems at a good rate of pay instead of berating the standard to vent your frustrations. I will happily give a price for delivering the course anywhere in the UK except Middlesbrough. Please feel free to email us for a quotation.
Stop Message Ends. Now off watch on this subject. Returning Home station for refreshments (including a large talisker.)
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Sorry for the long winded post but there you go….
CT - David, your interpretation of critical is as anomalous as your interpretation of the written word. The most critical doors need cat A.
DR – And who decides what doors are critical, the code doesn’t put responsibility on anybody except “a competent person.”
7273-4 Introduction
Often, the acceptability of the devices, and of the type of device used, will be determined by a risk assessment carried out by a competent person. Building control bodies and fire and rescue authorities can give advice in particular circumstances.
DR – well has anybody told them that because I thought this forum was populated by such persons but it seems that despite nearly 1000 views of this topic none have come forward to offer clarification of any part of this standard. Or is it simply testimony to the fact no one else actually understands it either?
CT- I regret the fact that, as a fire alarm specialist, you think those with expertise on means of escape are wrong in their interpretation of what is critical, but the concept of criticality espoused in the table to which you refer is a well established one, in which staircases in sleeping risks and single staircase situations are more critical than cross corridor doors in a office. This is fairly basic baby talk in fire safety principles.
DR – I can’t see where I’ve said anyone with expertise on means of escape is wrong in their interpretation of what is critical. Perhaps you could point it out?
To my simple mind, if a door on a staircase can fail to close for any reason (software failure or failure of the sounder knocked off the wall by the men shifting the office around) then personally I don’t want to be on the floor at the top of that staircase if a fire breaks out.
I still don’t see why there is one rule for acoustics and one for hardwired systems. I understand there is a concept of some doors more critical than others I just disagree that any door should be left open if the technology exists to close it as regardless of whether the door is on a staircase or subdividing a corridor the action of leaving that door open in a fire condition is increasing the risk to life and property in that area and beyond – bad karma?
From what I can see “those with the expertise” appear to have left the door open (!) for misinterpretation in favour of boosting sales of cheaper acoustic options by building owners, electricians, odd job men and fire companies (of which none of whom have ever heard of this standard or care.)
I have referred to the table in Annexe A which shows that some doors can in particular instances be categorized A, B or C. I find this a little ambiguous as again, I have no misconception that we are competent to be able to carry out a risk assessment and make a judgment as to how these doors should be categorized, but even less competent is the building administrator who wants the cheapest option. Again, the standard puts it in the hands of the enforcers who in my experience so far have less knowledge of the standard than I do, or choose to ignore it, and by virtue of these facts would appear they too are not competent to make such assessments.
“This annex describes the category of system that is likely to be specified
(e.g. by other standards or by enforcing authorities/bodies) in particular
circumstances.”
At the moment we have Joe Public who has gone and bought very well marketed acoustic devices and installed them anywhere and everywhere without thought of assessment or “categories” and I haven’t heard of any devices being removed at the request of the “enforcing” authorities in any of the big office/public buildings that we maintain. And being incompetent, who are we to suggest to the client they should be removed and replaced with a Cat A device?
Perhaps we should give them your phone number ?
CT - And you have not read what you wrote again. Nowhere does it say every acoustically linked device must receive the appropriate SPL from 2 sounders. If, however, there were acoustically linked hold open devices on two staircases that were not separated by fire doors then the two could not rely on a single bell. Is this really really very difficult to understand, because, to me, it is what you wrote correctly and then apparently misinterpreted what you wrote down.
DR – Well if you read what I wrote again, you will note I asked a question for clarification, I didn’t make a statement. But the following clause to which I assume you refer doesn’t seem to mention staircases separated by fire doors as you do it simply mentions the number of locations, or have I misinterpreted it again?
11.4 In the case of acoustic actuation, failure of any single fire alarm sounder should not prevent the actuation of release mechanisms for self-closing fire doors at more than one location at which the doors protect stairways that form means of escape in the event of fire.
I have buildings where acoustic devices are installed on two sets of doors (forming a lobby) on various floor levels off a staircase and buildings where devices are installed on double doors to the staircase, and perhaps 10 metres away down the corridor on more double doors dividing the corridor. In each case there is a single sounder within ear shot of these devices. General alarm levels in the buildings are acceptable.
So would you interpret all these doors in the two examples as being in the same location and therefore the single sounder in earshot arrangement acceptable?
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Wizzy, I had no idea people were simply seeking advice on things they found too difficult to understand. Now I see things much more clearly..... I was previously misled by comments such as (and I quote):
men in black overcooked it
To quote it properly I asked
"So what does it actually take to get the men in black to admit they've overcooked it and rethink ??"
Hardly a berating statement of the standard or the writers.
I too can appreciate the the reason for the standard. I admit I find it very difficult to understand and interpret and haven't met anybody else - fire alarm system engineers, control officers, architects, consultants or fire officers yet who can explain it fully.
I don't think that means we are all thick, it suggests to me the commentary is insufficient and the wording of parts of the standard is not clear enough to the target audience it's aimed at.
It's not a personal critisism it's just a fact.
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I see it talks of acoustic coupling as well - been a long time since I had an acoustic coupling as our two boys are light sleepers.
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David, Thank you for your offer to market our services. The number is 01252 792088. Of course you should tell them to get a consultant if they cannot deal with something themselves. Many thanks in advance for the future referrals.
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David, Thank you for your offer to market our services. The number is 01252 792088. Of course you should tell them to get a consultant if they cannot deal with something themselves. Many thanks in advance for the future referrals.
No problem Colin, I'll include it within the emergency pack containing bushmills, prozac and the number for the local samaritans....! ;)
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Also pass it on to Wizzy fire alarms as he has not ordered the course yet
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Wizzy, I had no idea people were simply seeking advice on things they found too difficult to understand. Now I see things much more clearly..... I was previously misled by comments such as (and I quote):
waste of paper
hands up, I didnt buy it
burn it. best thing you can do with it
men in black overcooked it
and the best one of all (from an ex enforcer) I ignore it completely.
Had I realised that all this somewhat puerile ranting was simply a request to understand a standard that is a bit tricky for non fire alarm engineers (and, yes maybe for some engineers), I would have tried to help. However, from the comments as I re-read them all today, I think many of those are beyond help, particularly those outside the fire alarm industry who cant be bothered buying it, or who think they are so much above it that they ignore it. (As a matter of record, I dont think you fit into these categories, but are merely frustrated that you cant understand some of the philosophy and practice. I can relate to this as I find the same problem in using a video recorder and, on the basis that I find "The simple guide to brain surgery" is somewhat dificult to understand, and I am not in the field of brain surgery anyway, I tend to ignore it completely too).
Clearly, your conceptual and practical, but I suspect genuine, difficulties with the standard cannot be resolved by a few simplistic words of advice here, nor are they assisted by people who dont understand the technology in the first place jumping on the bandwaggon.
Accordingly, I am pleased to offer the Wizzy fire alarm co unlimited a course on the standard at a specially discounted rate. This is a course that has been presented as a public course for some time, but it is now formally available to the Wizzyco as an in-house course. The good news is that the whole course only takes half a day as the standard is so simple. The bad news is that, even at the discounted rate, it is quite expensive, but will repay itself in the time you could have been fixing wee alarm systems at a good rate of pay instead of berating the standard to vent your frustrations. I will happily give a price for delivering the course anywhere in the UK except Middlesbrough. Please feel free to email us for a quotation.
Stop Message Ends. Now off watch on this subject. Returning Home station for refreshments (including a large talisker.)
Colin, I accept that the comments you highlight have been made on this thread, but only one of them is by me. In response to someone saying they couldn't currently find their copy of BS7273-4, I light-heartedly wondered if they had 'burnt it, because that was the best thing to do with it!'
I maintain my opinion that this BS is confusing and difficult to understand. It seems that others agree with me. No-one on this forum, apart from yourself, has professed to understand it, but that shouldn't be a surprise, if you have been involved in some way with it's production.
We, who are prepared to state that we find it difficult to understand, are those that want to make it work.
If we are making the comments that we find it frustrating and difficult to understand, do we deserve to be treated as idiots? We have two options; one is to pretend to understand it, the other is to admit to not understanding it and to seek help with input from others on this forum. Obviously, this 'input' may not always going to your liking, but we are entitled to our own opinions.
I have been considering your very kind offer of a half-day course on BS7273-4 at a discounted rate. I have discussed it with my colleagues (There is no Wizzy fire alarm company as you believe, but I do have daily contact with a large number of people who would possibly benefit from such a course)
My discussions with these people have revealed two concerns to their potential interest in attending such a course.
Firstly, they say they are not interested in a course that would be presented in a manner that was sarcastic and arrogant. Can you provide them with any reassurances on this point?
Secondly, they wonder if such a half-day course would really be sufficient for them to get a even a reasonable understanding of the subject, based on their difficulties in understanding what has been written in the BS? To ascertain this they have asked me to ask you if the 'course trainer' could first provide an explanation on this forum, of the following single sample BS 7273-4 clause;
5.1.3 Category C actuation
Category C actuation is designed to be fail-safe under the conditions of Category B actuation, but, in Category C actuation, there is no direct communications path between the fire alarm CIE and the release mechanism; actuation of the release mechanism is facillitated by other control, or similar, equipment (e.g. the control equipment of an access control system, or of an electrically controlled hold-open system).
Accordingly, any circuit between the fire alarm CIE and other control equipment needs to fail safe (see 10.6). It should be noted that, in category C actuation, the critical signal path is deemed to end at the other control equipment. However, it is preferable, subject to conformity to the relevant standard for the other equipment, that the release mechanism is actuated in the event of an open or short circuit of wiring between the the other control equipment and any release mechanism (see Note 10.6)
I appreciate the difficulties in trying to understand such a clause presented in the manner above and without reference to the notes and terms and definitions etc., but my colleagues hope to be able to use the explantion in tandem with what they can read in their copies of the BS, to ascertain their ability to get a worthwhile result from the proposed course.
I thank you for your help in this matter and hope we will be able to take you up on your offer.
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1. Wizzy. There is nothing certain in life other than death, taxes and chewing of gum by the inspecting officers of a large metropolitan fire and rescue service. So, I can offer no assurances of anything. I tend to meet fire with fire, and the postings in this thread are mostly along the lines of I can't understand it , so it must be rubbish, rather than I can't understand it, could someone explain. I find this arrogant and ignorant. I would love to know why the universe is expanding, but find books on quantum physics very difficult to understand, but I tend not to be-rate them and make stupid comments about them such as certain posters, other than your goodself, have made. Given that the standard was endorsed by just about every organization that is anything in the fire world, I find it difficult to believe that there is a fundamental flaw in the standard, rather than a flaw in the capacity of some people (other than your goodself, who merely have some difficulty with the practical engineering of some of the recommendations) to understand quite basic fire safety principles that I thought were adequately explained in the commentary of the clauses (which is why, when invited by BSI to write a guide to the code of practice, I thought there would be no market for it).
2. I have been doing public half day courses in BS 7273-4 for some time, and training is 20% of the turnover of our consulting practice. Under our ISO 9000 system, the delegate feedback on every course we do is independently analysed. At last count, delegate satisfaction was running at around 90% across all the courses we do. Our last customer complaint was in 2006, and related to lack of political correctness in describing how an optical smoke detector works (which I still maintain is related to the fact that women can never see to drive through fog because they never dip the bleeding headlights). The view I take is that the lady in question will now never forget how an optical smoke detector works AND she will dip her headlights when she drives through fog, making the roads of Britain safer for the rest of us to drive on (and all this included in the course fee).
3. You can have as long as you want for the course. If you wish to pay for a day, that's fine too. We can spend some of it talking about Joanna Lumley's legs, as we will probably run out of things to say about BS 7273-4, since understanding the recs is easy as falling of a log (albeit that going away and engineering them may take some time and effort). I find Joanna more interesting than BS 7273-4, though as she ages it becomes more and more a close run thing.
4 Alas, it is not company practice, to do free offers as incentive to buy training, and since, whether we sell a half day course or not will make little difference to the company shareholders, its not something I am inclinded to do. Equally, I cannot believe anybody has difficulty understanding the clause you describe, particularly as we drew a picture to support it. If you look at the drawing, the clause is prefectly clear. Not only that, but that very clause was discussed in depth with a security body to make sure they could understand it before we finalized it. It is a bit tricky to comply with, but then it is only a RELAXATION of a previous recommendation of BS 7807, which the fire alarm industry (and no doubt ex enforcers selling their expertise as consultants) seemed to ignore, so we made it less onerous.
As I am now very bored with this subject, please contact us if you wish to have some training for WIZZYCO at a favourable rate. Otherwise, to be honest, I feel sure if you just spend a little more time going through the standard, it will all fall into place and you can save WIZZYCO money. Joking apart, I do hate to take fees for something that does not really need specialist input, but if you feel you really do want that, you are welcome to buy a course.
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Colin, thank you for your reply.
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Further to previous posts about how to interface to a BS7273-4 system, this, after much discussion with equipment manufacturers, by advice on this forum, and some deep thought on the matters are my understanding of how we can meet the BS recommendations for category A systems with the equipment currently available:
Non-addressable systems
The interfacing to the fire alarm system can only be carried out at the control panel.
All EN54 panels should have the recommended monitoring in clause 5.1.1 (except possibly the one for disablement) to operate the panel's fault relay, as standard. Some panels also have the disablement monitoring (either operating the fault relay or a seperate disablement relay). A panel that can monitor all the faults recommended in 5.1.1 is required. All these fault conditions would need to be tested on commissioning.
The fire, fault, and if seperate, disablement relay contacts would all be wired in series to the fail-safe BS7273-4 signalling relay. At least one of the fire, fault & disablement relays would have to be normally energised. (I understand that EN54 requires this of fault relays).
Addressable systems
If the interfacing is to be carried out at the panel then the requirements are as the non-addressable system above.
If the interfacing is on the addressable loop then an interface that is loop powered energised in it's normal condition is required (Hochiki manufacture such a device). With other interfaces it will be necessary to also wire a simple relay powered from the loop and wire the contacts of both relays in series to the fail-safe BS7273-4 signalling relay.
I would welcome comments from those that are interested in the above summary so that we can 'tweak' it until it is correct and understandable to everyone.
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Addressable systems
If the interfacing is to be carried out at the panel then the requirements are as the non-addressable system above.
If the interfacing is on the addressable loop then an interface that is loop powered energised in it's normal condition is required (Hochiki manufacture such a device). With other interfaces it will be necessary to also wire a simple relay powered from the loop and wire the contacts of both relays in series to the fail-safe BS7273-4 signalling relay.
I would welcome comments from those that are interested in the above summary so that we can 'tweak' it until it is correct and understandable to everyone.
Hello Wiz...
Seems about right to me.... my only question is still regarding the action of the Hochiki I/O - do you know if it changes state on "software failure" and what that means?
Re the "other interfaces" I've also been advised by Apollo in the past not to power relays directly from a loop... but just to be clear, are you suggesting a relay connected to the loop (permanently energised) in turn connected to its own closed contacts (open on power fail) in series with the normally closed on the I/O (the "part 4 relay") so if either one opens the magnet releases?
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Addressable systems
If the interfacing is to be carried out at the panel then the requirements are as the non-addressable system above.
If the interfacing is on the addressable loop then an interface that is loop powered energised in it's normal condition is required (Hochiki manufacture such a device). With other interfaces it will be necessary to also wire a simple relay powered from the loop and wire the contacts of both relays in series to the fail-safe BS7273-4 signalling relay.
I would welcome comments from those that are interested in the above summary so that we can 'tweak' it until it is correct and understandable to everyone.
Hello Wiz...
Seems about right to me.... my only question is still regarding the action of the Hochiki I/O - do you know if it changes state on "software failure" and what that means?
Re the "other interfaces" I've also been advised by Apollo in the past not to power relays directly from a loop... but just to be clear, are you suggesting a relay connected to the loop (permanently energised) in turn connected to its own closed contacts (open on power fail) in series with the normally closed on the I/O (the "part 4 relay") so if either one opens the magnet releases?
Hi Dave - as 5839/en54 recommendations the CIE should indicate a fault due to sotware failure anyway via the watchdog so I (personally!) think it's a red herring.
I'm still missing the failsafe recommendations of the actual I/O but maybe I just get snowblind when it comes to that part!!
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Addressable systems
If the interfacing is to be carried out at the panel then the requirements are as the non-addressable system above.
If the interfacing is on the addressable loop then an interface that is loop powered energised in it's normal condition is required (Hochiki manufacture such a device). With other interfaces it will be necessary to also wire a simple relay powered from the loop and wire the contacts of both relays in series to the fail-safe BS7273-4 signalling relay.
I would welcome comments from those that are interested in the above summary so that we can 'tweak' it until it is correct and understandable to everyone.
Hello Wiz...
Seems about right to me.... my only question is still regarding the action of the Hochiki I/O - do you know if it changes state on "software failure" and what that means?
Re the "other interfaces" I've also been advised by Apollo in the past not to power relays directly from a loop... but just to be clear, are you suggesting a relay connected to the loop (permanently energised) in turn connected to its own closed contacts (open on power fail) in series with the normally closed on the I/O (the "part 4 relay") so if either one opens the magnet releases?
Dave, my understanding is the 'software fault' monitoring is a standard requirement of the current EN/BS for control panels. What this actually covers, I don't know because I don't design control panels. Obviously, there is some sort software fault monitoring on control panels and this will give a panel 'fault' condition.
So the C&E would be that any fire or fault condition monitored by the the cie would operate the addressable loop output interface. If the panel fault condition also operated on disablements then no further action is required. (although it seems the disablement function giving a fault condition isn't a standard requiremnt of the EN/BS for panels)
However, most addressable panels have a seperate disablement warning (i.e doesn't necessarily create the fault condition) so in this case the C&E would be either a fire/fault/disablement condition on the cie would operate the addressable loop output interface.
To cover the requirement whereby the interface fail-safes on loop power failure we would need an interface that was energised on in the normal condition and fail-safe de-energised on loop power failure. Evidently one of the Hochiki models does this.
Evidently, the Apollo output units don't do this because they have more of a 'flip-flop' style relay which might stay in it's last state even after power disconnection. In this case if we use a simple standard relay kept energised from the loop and wired it's contacts in series with the addressable output unit, either relay changing state (the addressable on fire/fault/disablement data received , and the standard on power failure) will provide the signalling circuit to our 'part 4' system. I note your comments about not powering a standard relay coil from the loop. I could see that back emf etc. might cause problems. I've powered other stuff from the loop with no problems but never relays. I'm going to talk to Apollo about this. It might mean a 'special' relay or relay circuit is going to be required.
Going back to the software fault, it would seem that this doesn't have to include loss of data on the loop. I thought that it might. Buzz previously highlighted that the BS doesn't specifically mention it. So I think he is right. We just need to know when the panel detects a 'software' fault as determined in the panel standards.
This BS recommendations don't seem to provide a perfect fail-safe situation. But does this matter to us? At this time we're more interested in finding out how to make the BS work rather than any potential failings with it.
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I have the solutuion to disablements ;D
set up all panels in future with restricted access so the end user cannot disable anything only an Engineer.
So if a customer gets a fault,the fault relay will shut the doors and he will have to call out an engineer of he wants them to stay open again.
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I have the solutuion to disablements ;D
set up all panels in future with restricted access so the end user cannot disable anything only an Engineer.
So if a customer gets a fault,the fault relay will shut the doors and he will have to call out an engineer of he wants them to stay open again.
Your'e getting desperate, Graeme! Next you'll be suggesting that we disable the end-users so they can't touch the fire panel!
I know your post was in jest, but disablements, even by an engineer, have to operate the release mechanism interface. Also I have found that there are a reasonable number of panels out there with disablement relays, but nowhere near all of them because it is evidently not a requirement of the cie design EN/BS.
By the way, the BS is only looking for disablements that are capable of affecting the correct operation of the release mechanisms, but I can't see anyone taking the time to wire/configure so that only if detectors a or b are disabled will door x release automatically, and only if detectors c, d or e are disabled will door y release automatically. I suspect that it in practice designers will just want any disablement to operate all release mechanisms.
Also we have found that there are a reasonable number of panels out there with disablement relays
I can't wait until the scaremongering about having to comply with this BS begins - I will enjoy watching the ensuing panic. I might even start the scaremongering myself, if I ever work out how to comply with all parts of the BS!
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So.... if you can set up a system eg 10 storey office block and in a quite simplistic scenario program detectors/callpoints to release doors on the floor of origin only - the detectors that are "capable of affecting the correct operation of the release mechanisms"....
does that mean that when testing as required in 7273-4...
22.1.1 Every week, a fire alarm signal(s) should be used to cause actuation of all release mechanisms. It should be confirmed that each
release mechanism operates correctly and that the doors close properly, unlock or revert to the fully open position, as appropriate.
This test should normally be carried out at approximately the same time each week.
...... you should then test a call point on every floor level once a week to prove the release "path" is fully working?
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So.... if you can set up a system eg 10 storey office block and in a quite simplistic scenario program detectors/callpoints to release doors on the floor of origin only - the detectors that are "capable of affecting the correct operation of the release mechanisms"....
does that mean that when testing as required in 7273-4...
22.1.1 Every week, a fire alarm signal(s) should be used to cause actuation of all release mechanisms. It should be confirmed that each
release mechanism operates correctly and that the doors close properly, unlock or revert to the fully open position, as appropriate.
This test should normally be carried out at approximately the same time each week.
...... you should then test a call point on every floor level once a week to prove the release "path" is fully working?
Two tests - one as per normal requirements on a different MCP and the other on a general alarm input (evac button??) that drops everything??
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So.... if you can set up a system eg 10 storey office block and in a quite simplistic scenario program detectors/callpoints to release doors on the floor of origin only - the detectors that are "capable of affecting the correct operation of the release mechanisms"....
does that mean that when testing as required in 7273-4...
22.1.1 Every week, a fire alarm signal(s) should be used to cause actuation of all release mechanisms. It should be confirmed that each
release mechanism operates correctly and that the doors close properly, unlock or revert to the fully open position, as appropriate.
This test should normally be carried out at approximately the same time each week.
...... you should then test a call point on every floor level once a week to prove the release "path" is fully working?
david, I think your question is answered in 22.1.2
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ooops.... sorry didn't get that far.....!
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I have now identified a cie that runs XP95 that has the fire/fault/disable relays that would allow connection from the cie to the BS7273-4 system. I am told by the manufacturers that this cie complies with EN54 and so, according to what we have been told on this forum, will therefore monitor all the faults conditions required of the fire alarm system for this sort of system.
Furthermore I have identified a loop powered addressable output relay that runs on XP95 protocol that when used in conjunction with the cie mentioned above, will allow a special loop-powered interface to be used. The panel C&E programming software can be used to write a programme that will keep the interface enrgised in the normal condition and release it on either a fire, fault or device disabled condition. If the interface loses loop power it will fail-safe denergised.
I believe that the above is everything required to control Category A systems of BS7273-4
The C&E programming software also provides the ability to make the loop-powered output de-energise on single or groups of detection devices and for zones of detection devices etc.
I am willing to provide details of the cie, the 'special' addressable output relay and the required C&E programming to those who are interested.
However, I've learnt from some people on this forum that you shouldn't do anything for nothing and I'm therefore going to make a charge of £10 to each person who wants the info. All proceeds from this will be given to a charity of my choice.
If you are interested please PM me and I'll provide details of how you can pay to obtain this information.
David R, Buzz and Graeme - I have PM'd you a message
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...will you be sharing this information via a 'half day course' ;D
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...will you be sharing this information via a 'half day course' ;D
Very good! It could happen, you never know ;)
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Thanks Dr Wiz for your work on this. Whilst your technical analysis and proposed solution is above my head (and I guess the majority of my peers) it is very useful and enlightening. I have been ploughing through the document itself prompted by the issues you raise. It strikes me as an esoteric mix of information, partly founded on performance based standards which will not relate to anyone other than the designers of CIE or software protocols, with a broad base of functional requirements founded on common sense to which I and my peers in fire risk assessment can relate but perhaps beyond the normal considerations of the equipment designer. It is of course most relevant to the M&E design team for new buildings. Because the standard is so dependent on the CIE and software protocols perhaps it would have been more widely understood if it had been part of the BS5839 or EN 54 series?
To me it would be a bit like a highway code that instead of simply setting out overall braking distances for the education of drivers also set out the technical performance for the cadence braking applied by the ABS system.
Certainly whilst it raises essential considerations for the fire risk assessor, for use in assessing everyday fire safety issues and problems in existing premises with existing alarm systems (eg wedges in persistent use or old ladies being knocked over by fire doors) it would appear very difficult or expensive to achieve BS7273 part 4 compliant solution.
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... Spot on K.... and from a contractors point of view, do we
a. try and comply but lose the job as our costs are considered excessive, eventually declare ourselves bankrupt, hand back the sky dishes and put a dozen people on the dole
b. not comply but sign a 5839 compliance certificate (may be slipping in a variation) like most other installers who most likely are ignorant of 7273 or don't care, rake in the profits and go and live in essex, apparently one of the safest area in the country?
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Prof. K, I trust you had a nice holiday but I hope your post is not a criticism of BS7273-4! You might regret it if it is! (I can't tell if it was a criticism - using words such as esoteric is above my head - for an explantion of my poor educational standards please see below)
David, your fears are understandable, but you should look at the BS as an opportunity rather than a hinderance. If we ever get to understand it fully and know how to comply with it (and you know how hard we are struggling to do that!) then you will be one of the few that can install to that standard. In fact, you'll be able to start prompting the designers to include reference to BS7273-4 in their specifications, and really give the other installers something to think about!
I also thank you for your comments regarding the safety of Essex. I have lived in Essex for most of my life and my business has been based in that beautiful ;) County for 28 years, partly servicing/installing but mainly now just supplying equipment, design & commissioning services and technical back-up to installers and I have undoubtedly 'raked in the profits'. Small as they are - I still rake madly and continuously!
I am therefore obviously entirely responsible for making Essex one of the safest areas in the Country! :)
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I am therefore obviously entirely responsible for making Essex one of the safest areas in the Country! :)
God bless the humble modest engineers for they shall (or is it should) receive their badge of competency (following a risk assessment on working at heights) in heaven........!!