7273 and location of detectors

[Wiz]

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

[Allen Higginson]

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??

[Wiz]

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

[Wiz]

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.

[Wiz]

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.

[colin todd]

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.

[Wiz]

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!

[Wiz]

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'

[David Rooney]

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..... ?

[colin todd]

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).

[Wiz]

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.

[colin todd]

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.

[David Rooney]

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)
 

[Allen Higginson]

On the whole software thing - what section mentions data signals?

[Wiz]

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.