FireNet Community
FIRE SERVICE AND GENERAL FIRE SAFETY TOPICS => Fire Safety => Topic started by: Paul2886 on July 28, 2009, 06:07:43 PM
-
Your views please. Do you consider it necessary to link an electronic lock, on a final exit door, to the fire alarm system if its fitted with a green break glass box. Some varying views here at my neck of the woods.
-
See the topic on BS 7273 part 4 and try to gain an insight from that.
-
Nah, No one can understand BS 7273-4. Its all too difficult (apparently!!!!!!!!!)
-
If you are asking for opinion rather than code, then I would say yes - default to the highest level of safety, unless your risk assessment can justify a lower standard.
Mag locks are increasingly used on doors where the occupancy & risk has previously deemed an anti panic fastening is required - if you are relying on someone identifying a little green box in a panic situation you might as well replace the panic bolts with a key in glass fronted box, as the exit is no longer panic proof. But if you have a fire alarm link then the mag locks should be dropped as people reach the door and it becomes panic proof on the bolts alone.
There is considerable ignorance about green & white override boxes by general staff and they are either totally overlooked and not understood, rarely being used in drills (where no alarm link is present) and peole either constantly using the normal push to exit or finding a different door - very little training seems to mention them.
-
This is the minimum standard I accept.
When considering the acceptability of electronically powered locks on exit doors ensure they meet all the following requirements:
they "fail safe" so that the door is unlocked in the event of power failure, system error or failure of the alarm system; and
they are unlocked automatically on the activation of the fire alarm; and
there is an easily operated override at the door.
The first of these points requires some clarification as it has come to light that some installations have been considered to "fail safe" when they failed to the locked condition for security reasons. Clearly in the case of fire exits this is never appropriate and "fail safe" must always mean failing to the unlocked position.
The third of these points also requires some elaboration, the standard requires them to be fitted only with a lock or fastening which is readily operated, without a key. This means the operating devices must be useable by anyone in the building and so would normally prevent the use of card operated locks, unless there was an emergency override (Green box).
Also
The Scottish guides technical annexe goes on to state:-
Electrically powered locks should not be installed on any door where it is:
The only route of escape from a building or part of a building
A protected door serving a fire fighting shaft.
Serving any room or storey with an aggregate occupancy capacity exceeding 60 persons.
-
Your views please. Do you consider it necessary to link an electronic lock, on a final exit door, to the fire alarm system if its fitted with a green break glass box. Some varying views here at my neck of the woods.
This is an interesting question.
BS7272-4 starts with 'It is now commonplace for there to be an interface(s) between the fire detection and alarm system and various forms of door hardware'
Therefore it would appear that BS7273-4 only contains the recommendations applicable where there is such an interface. It doesn't appear to provide the recomendation that you have to link the two systems.
Is the need for having any interfacing link between fire alarm systems and electrically release mechanism on doors covered by any other authorative document, rather than just the opinions of individuals?
Does anyone know?
-
The Scottish guides technical annexe goes on to state:-
Electrically powered locks should not be installed on any door where it is:
Serving any room or storey with an aggregate occupancy capacity exceeding 60 persons.
Which implies doors liable to be fitted with anti panic fastenings - yet here in E&W they are spreading willy nilly.
Agree with your own requirements BTW
-
From a common sense point of view, why would you require a green box on an electomagnetic lock that will fail safe and is interconnected to the FA system?
-
From a common sense point of view, why would you require a green box on an electomagnetic lock that will fail safe and is interconnected to the FA system?
FSO your question has previously been answered on this forum by Mr Todd. It has to do with the number of people who have been/or could be trapped and die in a burning building if the fire alarm system did not signal the fail-safe release properly and there was no Emergency Door Release available.
The British Standard version of recommendations for achieving what is required can be found in BS7273-4 : 2007.
But the original question asked was actually the other way around - If you have the green Emergency Door Release, who says you also need the link to the fire alarm system? I think it is a good question and await the answer with interest.
-
Thank you Wiz.
I still fail to see why the system would not work.
If the FA system interlock worked, then job done.
If the FA system did not work then push the button that they do every day to open the door.
If the power fails, job done.
-
Thank you Wiz.
I still fail to see why the system would not work.
If the FA system interlock worked, then job done.
If the FA system did not work then push the button that they do every day to open the door.
If the power fails, job done.
The problem could arise where damage to the cabling to the locking device, or the rocker switch/button (generally single pole) or an earth fault could interfere with the "failsafe design" and prevent the locking mechanism from releasing. Hence the need for a double pole switch to physically disconnect all power from the locking device.
Of course this isn't necessary if you have a single action "turnkey" or similar that allows you to open the door from the secure side in the direction of escape.
If the door can be used to escape in both directions you wouldn't really want a turnkey on the secure side ..... or even a breakglass come to that.... see the various notes/commentary/clauses on secure locations etc..... hence risk assessment.
-
Is the need for having any interfacing link between fire alarm systems and electrically release mechanism on doors covered by any other authorative document, rather than just the opinions of individuals?
Does anyone know?
7273pt 4 mentions "Guidance on the security of buildings against crime, including the use of locking devices, is given in BS 8220" but I don't know this document or what it might refer to... and not spending £100 to find out....!
-
Thank you Wiz.
I still fail to see why the system would not work.
If the FA system interlock worked, then job done.
If the FA system did not work then push the button that they do every day to open the door.
If the power fails, job done.
FSO, the 'normal' exit switch you are talking about is the switch I call the 'Request To Exit' Switch.
Firstly, not all doors have a Request To Exit switch i.e some electronically locked doors are only to be used in an emergency and have no switches.
Secondly, not all 'Request To Exit' switches are wired in 'series' with the power feed to the locking device. The ones that are, are those which unlock the door only as you depress the switch and where the door locks again immediately when you release the switch. If you had this type of switch you could possibly argue that it is only doing the same thing as the 'green box' (which I call the Emergency Door Release) would do i.e breaking the power feed to the locking device. However all Emergency Door Releases meeting BS7273-4 recommendations need to be double pole and your RTE switch would also have to be double pole for the following safety reasons; Whilst it is true that an accidental disconnection of the wiring to a single pole RTE switch would release a fail-safe release mechanism, an accidental short of the wiring to a single pole RTE would actually short out the switch contacts and keep the release mechanism energised even when the RTE was operated!! The double-pole requirement is meant to avoid short circuits allowing this to happen.
Thirdly, many RTE switches are not wired as above. With the above scenario, it can be annoying when the door locks immediately you release the button (i.e if you are carrying something you have try to press the RTE switch with your elbow and open the door with your foot before you release the switch!)
The method of connecting RTE switches asscociated with a keypad/or proximity reader on the entrance side of the door is different. They normally have dedicated connection terminals for a RTE switch. If you wire the RTE to these terminals what happens, is that when you operate the RTE switch, it opens the door for the same period of time programmed into the keypad/reader controller for 'door open' time. i.e. pressing the RTE button causes the system to unlock the door for the same pre-programmed period of time as if someone has entered the correct code into the keypad/shown a valid token to reader that is on the entry side of the door. This makes the door much easier to use, press the RTE and the door stays unlocked for a few seconds.
However, the type of RTE switch usually required for this connection method is a Normally Open switch. This means its wiring is not monitored for disconnection i.e. a wire disconnecting from it won't cause the lock to fail-safe door open. Furthermore it is relying on the controller to accept the signal from the RTE switch and open the door. If the controller failed the door wouldn't open. In both these circumstances it is imperitive that a double pole Emergency Door Release is also provided and wired into the power feed to the door locking device. You certainly couldn't rely on just the RTE switch.
-
Your views please. Do you consider it necessary to link an electronic lock, on a final exit door, to the fire alarm system if its fitted with a green break glass box. Some varying views here at my neck of the woods.
Wow! This has got technical....
Returning to the original question, I think AnthonyB and Marty, early on, gave the ideal answer. But I've been in buildings that are huge (from Cathedrals to big sheds (and I mean big)) and to link every electronically secured door back to the alarm panel would mean literally miles of very expensive cabling. In such cases, is it not agreed that a reliable one of these
(http://dc161.4shared.com/img/121572400/6821956e/green_box.jpg) (http://www.4shared.com/file/121572400/6821956e/green_box.html)
is satisfactory as the sole means for ensuring that the door is always available for escape.....provided it also has one of these
(http://dc148.4shared.com/img/121572656/ffb11070/Green_box_sign.jpg) (http://www.4shared.com/file/121572656/ffb11070/Green_box_sign.html)
Stu
-
SEE WIZZY, you CAN understand BS 7273-4 just fine. And goddam it now that you do you like it so much that you want to extend its scope beyond that for which the BS 7273 suite was first invented. How cool is that. For your next task, I want to you to work on explaining Ohms Law to those amongst our enforcing authority chums who are arrogant enough to think if they cant understand it, it is not worthy of their attention. Use the analogy of water going through pipes cos they can relate to that.
-
Your views please. Do you consider it necessary to link an electronic lock, on a final exit door, to the fire alarm system if its fitted with a green break glass box. Some varying views here at my neck of the woods.
Wow! This has got technical....
Returning to the original question, I think AnthonyB and Marty, early on, gave the ideal answer. But I've been in buildings that are huge (from Cathedrals to big sheds (and I mean big)) and to link every electronically secured door back to the alarm panel would mean literally miles of very expensive cabling. In such cases, is it not agreed that a reliable one of these
(http://dc161.4shared.com/img/121572400/6821956e/green_box.jpg) (http://www.4shared.com/file/121572400/6821956e/green_box.html)
is satisfactory as the sole means for ensuring that the door is always available for escape.....provided it also has one of these
(http://dc148.4shared.com/img/121572656/ffb11070/Green_box_sign.jpg) (http://www.4shared.com/file/121572656/ffb11070/Green_box_sign.html)
Stu
Stu, You can't have understood my answer. I apologise that it isn't clearer.
There is no question that the equipment shown in your pictures is what might be required for a system. However, It is how you wire them up that is the important part! You could install the equipment shown in your pictures in a manner that would mean that the system didn't fail-safe if affected by a fault. BS7273-4 provides recommendations to reduce the liklihood of faults causing the door(s) to remain locked in an emergency.
BS isn't interested in the difficulties you might have in complying with it because of cost and/or effort in doing so just because your site is a cathedral or a big shed.
Your post seems to be more in-line with the original question (not FSO's off-shoot) and it would be interesting to find out why exactly 'it is now commonplace to find an interface between the fire alarm system and electrical release mechanisms', when these 'mechanisms' are doors.
My last answer was given in response FSO to a diiferent question from the original. It was answering the question as to why you can't rely on just a RTE switch and fire alarm link. i.e without any EDR.
You also have to understand two things; One, that there is often much more than first meets the eye. Just seeing a RTE switch and EDR switch installed doesn't mean that the system is fail-safe. Two, that on this forum you get both personal opinions of what someone thinks is sufficient, and also details of what the authorative standards and guidance recommend. It is your own choice to decide which you follow.
However, some people also want to understand the reasons behind what the recommendations are asking for or why it is common practice to do somethin. I considered FSO's question to be this sort. I therefore answered FSO's question in as much depth as my knowledge and experience extended to. I apologise if it was too technical but I hope I covered every angle for FSO :)
Most importantly please note that the original question posted has not yet been answered by anyone. In other words ,the question asked was, ' If an EDR (green box) is installed (lets assume it is installed properly to BS7273-4) then why does the release system need to be linked to the fire alarm? The underlying question being that, fire condition or not, anyone needing to exit that door in an emergency could always use the EDR. Seems a good question to me.
I subsequently asked if anyone knew of any authorative document that recommended the linking of door release mechanisms to the fire alarm system. There has been no answer.
-
SEE WIZZY, you CAN understand BS 7273-4 just fine. And goddam it now that you do you like it so much that you want to extend its scope beyond that for which the BS 7273 suite was first invented. How cool is that. For your next task, I want to you to work on explaining Ohms Law to those amongst our enforcing authority chums who are arrogant enough to think if they cant understand it, it is not worthy of their attention. Use the analogy of water going through pipes cos they can relate to that.
Colin, they say that sarcasm is the lowest form of wit, and whilst I accept that I have stooped somewhat low myself on occasions, you must be slithering around Firenet on your belly for much of the time!
I have never said that I understood none of BS7273-4, only that there is too much in it that is difficult to understand. My opinion is that it is a poorly written BS. I am entitled to my opinion and I know others share it. I have much more experience and knowledge of fire alarm systems and of understanding various guidance documents than you seem to believe, so I think my opinions are valid.
On this forum we have tried to get some discussion going in the hope that those of us who are interested in being able to comply with BS7273-4, find ways of doing so. This is in the hope of making the world a safer place, which I'm sure is also the intention of this BS. We had hoped to to receive some useful guidance from those who may have been involved in the production of this BS, but that has not materialised.
I have been unable to convince any of my colleagues to share the cost of the half-day BS7273-4 'enlightenment' course, not because we don't need it, but because we wonder why we should pay to be lectured in a condescending manner, when we can get that for free at home!
You previously said that you were bored with the subject of our complaints about BS7273-4, but you have continued to make sniping comments. Please, either give me some useful input to help me understand the BS, or just don't bother replying to my posts. I rarely find your sarcasm of anyone's posts on Firenet to have much humour.
-
Phoenix, if the route doesn't require anti panic fastenings and is used by persons familiar with the building who can be instructed about the fastenings, then as long as it's wired locally correctly as Wiz details then there may be grounds to accept it without a link to fire alarm systems.
As for authoritative documents requiring a fire alarm link to mag locks there are several in the form of Guidance Notes to the Fire Precautions Act issued by many brigades which set the minimum specification they would accept for mag locks in certified premises. Although the FP Act is gone a few brigades have retained the notes for responsible persons under the FSO to refer to.
This is, I think, the origin of the practice.
-
Phoenix, if the route doesn't require anti panic fastenings and is used by persons familiar with the building who can be instructed about the fastenings, then as long as it's wired locally correctly as Wiz details then there may be grounds to accept it without a link to fire alarm systems.
As for authoritative documents requiring a fire alarm link to mag locks there are several in the form of Guidance Notes to the Fire Precautions Act issued by many brigades which set the minimum specification they would accept for mag locks in certified premises. Although the FP Act is gone a few brigades have retained the notes for responsible persons under the FSO to refer to.
This is, I think, the origin of the practice.
That makes sense AnthonyB, and I suppose that now the FP Act doesn't apply, it is now all down to a risk assessment.
What do the guys doing Risk Assessments and the Fire guys doing inspections think about not linking emergency release mechanisms (only talking about doors held normally locked here) to the fire alarm system, as long as there is a correctly (BS7273-4) powered, wired and signed EDR (green box) appropriately positioned beside the normally locked door?
-
However, some people also want to understand the reasons behind what the recommendations are asking for or why it is common practice to do somethin. I considered FSO's question to be this sort. I therefore answered FSO's question in as much depth as my knowledge and experience extended to. I apologise if it was too technical but I hope I covered every angle for FSO :)
Yes thank you Wiz.
-
Gents
In MHO Anthony B got it spot on, if people don't know what it is they ain't gonna give it a bash
Also, please advise how I would know how it is wired when the wiring is not visible ???
We have over 200 of them, some with thumb twists on the doors, some without
davo
back two days and already missing me Amstel varellio megalo :'(
-
What do the guys doing Risk Assessments and the Fire guys doing inspections think about not linking emergency release mechanisms (only talking about doors held normally locked here) to the fire alarm system, as long as there is a correctly (BS7273-4) powered, wired and signed EDR (green box) appropriately positioned beside the normally locked door?
Well, a lot of these guys think it's just fine. But, just for argument's sake I'd like to hear Marty's opinion.
I think there's good answers to the original question embedded here and there in this thread.
Thanks for your elucidation, Wiz. I do have a further question though. You say this:
My last answer was given in response FSO to a diiferent question from the original. It was answering the question as to why you can't rely on just a RTE switch and fire alarm link. i.e without any EDR.
But I, and excuse my ineffective gleaning powers if you have made this explicitly clear earlier, am left wondering the following:
1. Are you saying that every electronically secured fire exit is unsatisfactory if it only has a red fire alarm call point next to it (as well as the obligatory RTE button, of course) to release the door? i.e. Should it also have a green emergency door release box?
2. If so, could you, for my simple brain, explain why?
Ta
Stu
-
What do the guys doing Risk Assessments and the Fire guys doing inspections think about not linking emergency release mechanisms (only talking about doors held normally locked here) to the fire alarm system, as long as there is a correctly (BS7273-4) powered, wired and signed EDR (green box) appropriately positioned beside the normally locked door?
Well, a lot of these guys think it's just fine. But, just for argument's sake I'd like to hear Marty's opinion.
I think there's good answers to the original question embedded here and there in this thread.
Thanks for your elucidation, Wiz. I do have a further question though. You say this:
My last answer was given in response FSO to a diiferent question from the original. It was answering the question as to why you can't rely on just a RTE switch and fire alarm link. i.e without any EDR.
But I, and excuse my ineffective gleaning powers if you have made this explicitly clear earlier, am left wondering the following:
1. Are you saying that every electronically secured fire exit is unsatisfactory if it only has a red fire alarm call point next to it (as well as the obligatory RTE button, of course) to release the door? i.e. Should it also have a green emergency door release box?
2. If so, could you, for my simple brain, explain why?
Ta
Stu
Stu, I am always happy to provide my understanding of these things. I think it is what Firenet should be used for i.e an exchange of information and opinions between people with a common interest.
1) The simple answer to your question is yes if you want to comply with BS7273-4, and, in fact, the practice that was most acceptable to those who know about these sort of systems even before that BS existed.
2) An electronically secured fire exit is probably the most dangerous (for life safety) of all types of release mechanism for doors. If the door can't be opened in an emergency people can become trapped.
BS7273-4 recommends that all such doors always have an Emergency Door Release (green box) (other than on doors in buildings where people are being lawfully detained -although these might need alternative precautions) The right type of EDR, and correctly wired, is meant to provide the best protection against failures in any of the other provided release mechanisms i.e link to fire alarm or Request To Exit switch.
Both the link to the fire alarm and the RTE switch have numerous possibilities for failure. The fire alarm link because it is so complicated and the RTE switch because it can wired in ways that are not fail-safe and also that constant normal use might make it more likely to fail.
The BS7273-4 recommendations for the EDR provide the best 'fail-safe' back-up for the failure of the other methods. If all else fails, the EDR is a switch wired in both legs of the power feed to the lock and is sited close, both physically and electrically, to the lock.
The above is the general background to my interpretation of the thinking behind the recommendations, and I am hoping that is what you want. I have explained the technical bits about the potential problems with the RTE switch in my previous answer. I hope that was sufficient. If you want to know about the potential problems with the fire alarm link, it would take me some hours to explain!
All of the above is my interpretation of the thinking behind the BS recommendations. It doesn't mean to say that I agree with them, or disagree with them, only that the above is my understanding of what the BS is trying to achieve and why.
-
Thanks Wiz. Very interesting.
Up until about ten or twelve years ago, before the emergence of these green boxes, all we had (and what we used to ask for) was a break glass fire alarm call point next to the door and the door interfaced with the alarm. We were quite happy with that and there are still thousands of doors like that around the country.
Fire alarms are interfaced with all sorts of life safety mechanisms, for example:
Lifts
Dampers
Escalators
Automatic opening vents
Pressure differential systems
Sprinkler pre-activation valves
Hold open devices on fire doors
Car park barriers
Fire shutters
Fire curtains
Entire smoke control systems in atria
etc
These are pretty important life safety interfaces. Some have manual over-rides, but these over-rides are generally for more complex reasons than being there just in case the interface fails.
In each case where such systems are interfaced it is assumed that the interface will work as planned. It is assumed that correct servicing, testing, fault correction and general maintenance will ensure that these interfaces perform as required when required.
I know you're just commenting on the standard but why do you think 7273-4 singles out electronic security locks to have this additional piece of equipment?
Seems over the top to me. I can get very cynical about such recommendations, especially when the industry has been involved in the development of the standard.
Stu
-
Stu, I don't disagree with some of your opinions. Sometimes belt and braces are not enough for some people, for them it has to be two belts and two braces, and others at least three sets! Where do you stop?
I've often said to people preaching about how they've made something fail-safe, that if they show me their 'fail-safe' circuit, I'll point out where it doesn't actually 'fail-safe'. Total 'Fail-safe is an impossibility!
I am not the biggest supporter of BS but for reasons other than those you mention. I disagree with you, for example, about the necessity of involving equipment manufacturers in the production of BSs. I think it is an imperitive.
Also, I believe absolutely that BS7273-4 has been written with the best intentions to make systems more reliable.
The people who devised the BS were obviously concerned about people being trapped in a burning building by not being able to use a locked door that has not released, and have tried to provide a solution by use of an EDR. I presume, the locked door scenario risk is seen to be higher than most, if not all, of the other systems you mention.
You would need to talk to these people about the reality of this risk, and if their methods of reducing it are the most appropriate. Mr Todd has made mention of these risks in various previous postings on Firenet.
-
I shall take the simpleton's view of it all. Ignoring any failsafe devices, any british standards, any electrical detail... What you want to avoid is a system where a failure of the fire alarm system also ensures that all the doors in the building remain locked at the time when they are most needed.
-
My similar simple view...
All electronically locked doors on fire escapes should generally release automatically with the fire alarm simply because it saves people in a panic situation looking for a release mechanism be it handle/thumbkey/pushbar or whatever and may prevent a pile up of bodies crushed against a door preventing the one up against the door from using the mechanism even if he could find it.
In addition, if the door has a single action mechanical release etc that withdraws the latchbolt from the keep (like a pushbar/thumbkey arrangement) then no other form of release ("green breakglass") is necessary.
But all electronically locked doors on fire escapes without a mechanical release mechanism that rely on electrical connections to affect the release of the lock (such as mag locks/solenoids etc) must have a reliable absolute method of cutting power to the lock ie. double pole green breakglass directly in line with the lock.
-
Thanks again for your comments Wiz.
I am not the biggest supporter of BS but for reasons other than those you mention. I disagree with you, for example, about the necessity of involving equipment manufacturers in the production of BSs. I think it is an imperitive.
You don't disagree with me here actually, because I also know that it is essential that industry practitioners are involved in the setting of standards. I just know that committees are prone to human frailties, particularly the frailties that arise when some characters are more vociferous than others. This is just the way of the world, and there is nothing that can be done about it. Catch 22. I accept.
But this realisation and acceptance is important because it tempers my/your/one's faith in the standards. I get the feeling that you're with me on this point, Wiz, and I hope that most others in this field feel the same.
What you want to avoid is a system where a failure of the fire alarm system also ensures that all the doors in the building remain locked at the time when they are most needed.
This is true, but a properly maintained and tested alarm system shouldn't fail. In a shopping mall, it is of paramount importance that when the fire alarm actuates, the correct channelling screens drop, the air inlet ventilators open, the appropriate fans or natural roof ventilators operate, appropriate containment screens drop, dampers and shutters operate as required, HVAC system shut down or adapt as required and so on. All this is reliant on the alarm system operating correctly and we trust that this will happen. All I'm saying is, why can't we have the same faith when we're considering doors linked to the fire alarm?
As a pragmatist, I do have an answer to my own question. I'd just like to hear someone else's opinion.
Stu
-
Thanks again for your comments Wiz.
I am not the biggest supporter of BS but for reasons other than those you mention. I disagree with you, for example, about the necessity of involving equipment manufacturers in the production of BSs. I think it is an imperitive.
You don't disagree with me here actually, because I also know that it is essential that industry practitioners are involved in the setting of standards. I just know that committees are prone to human frailties, particularly the frailties that arise when some characters are more vociferous than others. This is just the way of the world, and there is nothing that can be done about it. Catch 22. I accept.
But this realisation and acceptance is important because it tempers my/your/one's faith in the standards. I get the feeling that you're with me on this point, Wiz, and I hope that most others in this field feel the same.
What you want to avoid is a system where a failure of the fire alarm system also ensures that all the doors in the building remain locked at the time when they are most needed.
This is true, but a properly maintained and tested alarm system shouldn't fail. In a shopping mall, it is of paramount importance that when the fire alarm actuates, the correct channelling screens drop, the air inlet ventilators open, the appropriate fans or natural roof ventilators operate, appropriate containment screens drop, dampers and shutters operate as required, HVAC system shut down or adapt as required and so on. All this is reliant on the alarm system operating correctly and we trust that this will happen. All I'm saying is, why can't we have the same faith when we're considering doors linked to the fire alarm?
As a pragmatist, I do have an answer to my own question. I'd just like to hear someone else's opinion.
Stu
I'd have to raise the point that the system shouldn't fail but sometimes does.Have you ever had the customer arguing with you that they aren't paying for the call out and associated part because you were only here last week doing the service.
Bit like the MOT being on as good as the day of the test!
-
In a shopping mall, it is of paramount importance that when the fire alarm actuates, the correct channelling screens drop, the air inlet ventilators open, the appropriate fans or natural roof ventilators operate, appropriate containment screens drop, dampers and shutters operate as required, HVAC system shut down or adapt as required and so on. All this is reliant on the alarm system operating correctly and we trust that this will happen. All I'm saying is, why can't we have the same faith when we're considering doors linked to the fire alarm?
It is my opinion that a failure of all those things at once will be nowhere near as much of a guarantee of a catastrophe as locked exit doors during a fire. I am not saying there wouldn't be a potential disaster, just that a locked exit during a fire just about guarantees it.
-
In some cases in residential care/mental health etc. it is desirable to have as few opening devices as possible. Whilst maintaining a high stanadard of fire safety.
As stated in one of the original posts to this thread, you must risk assess the situation, therefore if you don't need it, don't have it.
My personal view is that there should always be a fire alarm call point linked into the system adjacent to the door with electronic locking ( the method of protecting or operating this can be escalated, should the risk assessment determine it being needed ). So if someone needs to raise the alarm they are not restricted by a locked door.
I agree that we have so many engineered solutions in high occupancy and life risk buildings, that all are initially activated by the alarm system, and now we are saying it is unreliable and cannot be trusted !
I know of one consultant who as said that all bedroom doors with swing free self closers must be kept shut at all times, because the fire alarm system might fail - It must be me, that's missing something !!!!
For those wanting the extra comfort, I believe that 'Ochiki' do a fire alarm call point that is double pole, so you can have it doing both operations i.e. activate fire alarm and it also has a direct link to the lock to open it ( I am not an electrician so don't shoot me if that's wrong ).
-
Clive, Even when your risk assesment has determined what you would like to achieve, please remember that there is a BS (7273-4), that provides recommendations for these sort of systems. It states what equipment you need to have, where it should be sited, how it should be interconnected etc .etc.
I know that if I was in a court of law explaining why I had designed/installed any system I would like to have the defence of 'I followed BS to the letter' rather than I did what I thought was right or what I had seen done previously.
I'm not aware of any product from Hochiki that does what you mention, although there are any number of double-pole fire alarm manual call points available. However BS7273-4 does not recognise a combined fire mcp and emergency door release switch. It might seem to be a good idea, some might even consider it to be a clever 'solution', but if it don't comply with BS I wouldn't even consider it!
p.s. being an electrician is not necessarily enough to cope with the modern world of fire alarms, at the very least you now need to be an electricain with an extensive knowledge of fire alarm systems, or preferably, a recognised fire alarm specialist.
-
.......... I did what I thought was right ..........
Wiz. Thats what Tony Bliar said when he and Bush declared war on Iraq and failed to find non existant (surprise, surprise) weapons of mass destruction.
If that excuse is good enough for him I'll let you use it in the court of public opinion.
-
Buzzard and Civvy, you both make good points that support the stance of the BS. The good thing is that the BS is only a standard and comprises only recommendations; recommendations that should always be followed - unless there are very good reasons for an alternative approach.
Clive's comments I know of one consultant who has said that all bedroom doors with swing free self closers must be kept shut at all times, because the fire alarm system might fail - It must be me, that's missing something !!!!
indicate what might happen if you rely too heavily on a prescriptive approach.
No, it's not you Clive.
Stu
-
.......... I did what I thought was right ..........
Wiz. Thats what Tony Bliar said when he and Bush declared war on Iraq and failed to find non existant (surprise, surprise) weapons of mass destruction.
If that excuse is good enough for him I'll let you use it in the court of public opinion.
Nearlythere, as I said, to avoid problems I wouldn't rely on a 'Blair defence'. My defence, though with no guarantee of success, would always be of ensuring compliance with BS. No use of 'bright ideas' or 'shortcuts' suggested by those who don't realise their possible implications.
However, if I am ever before Justice Nearlythere, then I might use whatever lies will fool most of the general public, as you suggest :)
-
I agree that to follow the BS is the initial route, and the primary defence route.
But they are not a one size fits all, that is why we risk assess, and provide the most appropriate solution taking 'all' things into consideration.
When it comes to mental health or secure areas ( mental health or criminal ) , the BS's have to be adapted to suit. Yes it must be robustly done, and with the knowledge and experience to do that. The firecode has 'variations' to BSs in it, ( as do BSs themselves) . The BSs are an acceptable standard, but not a ' must do' ruling in all cases.
As we know a lot of the BSs are one persons or a commitees view on a subject area, not everything in them is backed by science, there is a lot of consensus of opinion, and possibly a few things plucked out of the air. They will generally cover a lot of projects, but not all.
Don't get me wrong I am not knocking them, and will continue to use them as the benchmark in 98% of cases, but as with all risk assessed and engineered/managed solutions, they are there to assist not bind.
-
Clive, as a system designer/installer, if anyone produces an authority in writing for me to deviate from the BS recommendations and totally idemnifies me from the consequences of doing so, and confirms that I have advised them of the consequences of doing so, they can have whatever they are prepared to pay for - and good luck to them !!! Failing that they get exactly what BS recommends whether they have a 'risk assessed variation', or not!
-
So Wiz,
As a designer, what answer do you give to my question at the very start of this topic. Thanks
-
Paul2886, I don't have a definitive answer to your question, unless it is that BS7273-4 naturally assumes that an electric release mechanism is always interfaced to the fire alarm system.
My very first reply to your original post clearly stated that I thought you had raised a very interesting point i.e If an EDR (green box) was correctly installed to a door with an electrcially held locked door, why bother connecting the the release system to the fire alarm system?
The posts went off at tangents at various times, as they are wont to do on this forum, and the reason for the recommendations requiring EDR's, and how and why they should be connected in a certain way, were discussed at length.
I regularly asked other members to comment on why we always linked systems with EDRs to the fire alarm system and asked if anyone was aware of any authorative guidance on this subject.
As far as I recollect no-one really answered your question.
Here is my guess as to how the current typical system set-up has evolved;
When electrically operated locks were first used on doors, someone (probably the fire service), quite understandably, requested that the system was linked to automatically release on a fire alarm condition. At this time there was no requirement for an EDR. probably, no-one thought such an item was required.
At some later time, probably due to a failure on a system somewhere, someone (again, probably the fire service) decided that a secondary means of release of the locking mechanism was required in an emergency, and the EDR was incorporated as an integral part of the system.
At an ever later time, it was decided that the EDR was to be wired as double-pole, for enhanced saftey reasons.
Finally, BS7273-4 was issued with recommendations on how the evolved system above, was to be designed, installed, commissioned and serviced. I don't think it even considered that systems with a correctly wired EDR might not need to be linked to fire alarm systems.
In my opinion, from a safety perspective, the order of importance of the elements of the typical release system are as follows:
1) Good quality reliable release equipment.
2) System wired as 'fail-safe'
3) Emergency Door Release switch
4) Emergency Door release switch wired as 'double-pole'
5) Link to fire alarm system
However, the above is my opinion only.
-
Thanks Wiz,
I appreciate the time you've given to this subject and certainly your last post. Its always great to hear the opinions of others and think you're probably right on how things evolved over the years.
-
Came across this thread - cant understand how I missed it last summer.
Dr Wiz the Fire Safety Order Guidance appendix B within each version of the guide gives us the answer to your question in post 5. Here is a heavily edited summary:
Management of electronic door-control devices
The use of such devices may be accepted by enforcing authorities if the responsible person can demonstrate, through a suitable risk assessment for each individual door, both the need and the adequate management controls to ensure that people can escape safely from the premises. In particular:
•Access control should not be confused with exit control. Many devices are available which control the access to the premises but retain the immediate escape facility from the premises.
•In public areas, when push bars are operated on escape doors in conjunction with magnetic locks, they should release the electromagnetic locks immediately and allow the exit doors to open.
•The requirement for exit control should be carefully assessed and should not be seen as a substitute for good management of the employees and occupants.
•The device should be connected to the fire warning and/or detection system.
•The device should incorporate a bypass circuit for immediate release on activation of the fire warning and/or detection system.
•Each door should be fitted with a single securing device.
•The emergency exit doors should be clearly labelled about how to operate them. •
•In premises where there may be large numbers of people, the devices should only be considered when linked to a comprehensive automatic fire-detection and warning system in accordance with BS 5839-1.
•There should be an additional means of manually overriding the locking device at each such exit (typically a green break-glass point).
Hopefully that answers that one- but does anybody have a view on PIR operated sliding doors on escape routes - eg at the entrance to a shoppng centre mall.
I was having a discussion with one of the largest installers of doors in Europe who is adamant that these doors do not require green boxes. You know the set up- sliding doors without a break out facility that are controlled by PIR, designed in accordance with BS7036-2 incorporating a big rubber bungee so they open on failure of the power supply, linked to the fire alarm system etc.
I think a green box is required in this case as the PIR is processor controlled so if it crashes the doors will not open unless the power fails or the alarm sounds. Often there is no fire alarm call point for public use near the exit doors for obvious reasons. The installer disagrees and has installed many thousands of doors without it being questioned before.
What do you think?
-
Came across this thread - cant understand how I missed it last summer.
Dr Wiz the Fire Safety Order Guidance appendix B within each version of the guide gives us the answer to your question in post 5. Here is a heavily edited summary:
Management of electronic door-control devices
The use of such devices may be accepted by enforcing authorities if the responsible person can demonstrate, through a suitable risk assessment for each individual door, both the need and the adequate management controls to ensure that people can escape safely from the premises. In particular:
•Access control should not be confused with exit control. Many devices are available which control the access to the premises but retain the immediate escape facility from the premises.
•In public areas, when push bars are operated on escape doors in conjunction with magnetic locks, they should release the electromagnetic locks immediately and allow the exit doors to open.
•The requirement for exit control should be carefully assessed and should not be seen as a substitute for good management of the employees and occupants.
•The device should be connected to the fire warning and/or detection system.
•The device should incorporate a bypass circuit for immediate release on activation of the fire warning and/or detection system.
•Each door should be fitted with a single securing device.
•The emergency exit doors should be clearly labelled about how to operate them. •
•In premises where there may be large numbers of people, the devices should only be considered when linked to a comprehensive automatic fire-detection and warning system in accordance with BS 5839-1.
•There should be an additional means of manually overriding the locking device at each such exit (typically a green break-glass point).
Hopefully that answers that one- but does anybody have a view on PIR operated sliding doors on escape routes - eg at the entrance to a shoppng centre mall.
I was having a discussion with one of the largest installers of doors in Europe who is adamant that these doors do not require green boxes. You know the set up- sliding doors without a break out facility that are controlled by PIR, designed in accordance with BS7036-2 incorporating a big rubber bungee so they open on failure of the power supply, linked to the fire alarm system etc.
I think a green box is required in this case as the PIR is processor controlled so if it crashes the doors will not open unless the power fails or the alarm sounds. Often there is no fire alarm call point for public use near the exit doors for obvious reasons. The installer disagrees and has installed many thousands of doors without it being questioned before.
What do you think?
Between 5588 Pt10, 7274 Pt4 & 9999 I can't see a specific requirement for a bypass switch (green box) Kurnal, so long as the other safeguards are provided.
However, under 9999
"......security grilles and shutters (roller, folding or sliding), loading
doors, goods doors, sliding doors and up-and-over doors, unless
they are capable of being easily and quickly opened. If power
operated they should:
1) be provided with a fail-safe system for opening if either the
mains supply and/or any alternative power supply fails;
2) be capable of being easily and quickly opened manually;
Could this also mean that the door should be quickly and easily opened by manual operation of switch?
-
Prof., not another document!
Is the Fire Safety Order Guidance appendix B document just guidance, or based on BS recommendations or law?
And when I take it into account, if it is at variance to the guidance document from the Outer Hebrides sheep-shearing station's fire service Assistant Chief Officer's Committee, which do I consider most important?
Personally, I think that the double-pole green emergency door release switch is the most important element of an access system in terms of safety. Any link to a fire detection and alarm system to automatically release the locked door may be a bonus, but if I'm trapped in a building, the ability to be able to use the EDR to make my escape through an otherwise locked door (whether the fire alarm system has operated or not) is paramount.
By the way, I recollect that BS7273 includes sliding doors in it's recommendations, which also include the need for a double-pole EDR. I also seem to remember that nowhere in BS7273 does it specifically state that access control systems should be linked to the fire alarm system, but it does provide recommendations on how it should be linked, if it is!
-
Might I just point out:
Guidance and BS aside... From the Fire Safety Order:
(f) emergency doors must not be so locked or fastened that they cannot be easily and immediately opened by any person who may require to use them in an emergency;
Subject to the usual 'where necessary' condition of course. Read into it what you will.
-
Out of pure interest......
With the exception of a workplace familiar to employees, how many members of the public can recognise and understand the purpose of the green box?
I may be wrong but I doubt it is a huge percentage.
-
FSO, a proper EDR is green in colour (safety?) and has the words Emergency Door Release printed on it.
I don't know if this is easily recognisable to the general public or if, in a panic situation, it is even harder to recognise.
The underlying point of your question is probably that automatic release of locked doors in a fire condition is far safer than relying on someone operating an EDR. I can see this point as very valid.
However, since much can go wrong with any interface between a fire alarm system to an access control system, I would much prefer to rely on the EDR (complying to BS7273-4) than the interface link, if it was a simple choice between on of the two options.
Obviously, most systems have both and I suppose that is for the best.
-
Prof., not another document!
Is the Fire Safety Order Guidance appendix B document just guidance, or based on BS recommendations or law?
Dr Wiz I am referring to the DCLG Guidance documents published by the Government in support of the Fire Safety Order.
My cut and paste (and edit) was from the following:
http://www.communities.gov.uk/documents/fire/pdf/150955.pdf
-
Prof., not another document!
Is the Fire Safety Order Guidance appendix B document just guidance, or based on BS recommendations or law?
Dr Wiz I am referring to the DCLG Guidance documents published by the Government in support of the Fire Safety Order.
My cut and paste (and edit) was from the following:
http://www.communities.gov.uk/documents/fire/pdf/150955.pdf
Thanks for that Prof.. I note that the document you refer to is applicable to Large Places of Assembley (300 persons or more). I wonder if it is applicable in other premises? I suppose someone could read all the various different guides to find out. I don't know what we would do with ourselves if there weren't so much guidance, recommendations and laws available for us to look at!
And is the fire alarm link mentioned in this document because it is guidance, or a recommendation or because it is written in law?
I did note, as well, that the document is the normal hotch-potch of guidance, recommendations and law and without any reference to which is which. It would be easy for anyone to believe an opinion is actually a law and visa versa.
I know I've mentioned this before, but it is one of my many gripes with so many different documents issued by various bodies about similar matters.
In the same vein, I recently read an interesting article stating that judges are actually making up Divorce laws on the spot because there is, evidently, very few laws in place. I never realised that they could do this. I thought their job was to interpret The Law as it was written. The article explained that because hardly anything was written up as being right and fair in any particular circumstances, the judges unillaterally just make things up as they see fit on a case by case basis! Can this be right?
-
[. I note that the document you refer to is applicable to Large Places of Assembley (300 persons or more). I wonder if it is applicable in other premises? I suppose someone could rwead all the guides to find out. I don't know what we would do with ourselves if there weren't so much guidance, recommendations and laws available for us to look at!
They are all pretty well identical in respect of Appendix B.
-
Intrestingly I was in IKEA at the weekend and noticed that they have EDRs fitted in the situations described by Kurnal.
-
EDRs for self assembly and probably unpainted?
-
Indeed Kurnal. Also complete with pointless pictorial instructions.
But I should not worry, because no doubt it will fall apart after a year of limited use anyway. :) ::)