Author Topic: Electronic Lock on final Exit  (Read 48545 times)

Offline lyledunn

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Electronic Lock on final Exit
« on: December 17, 2010, 10:50:23 AM »
I know that this is an old chestnut but looking at BS9999 2008;
"Except for premises in occupancy characteristic A, doors on escape
routes from rooms with an occupant capacity of more than 60 either
should not be fitted with lock, latch or bolt fastenings, or should be
fitted with panic exit devices in accordance with BS EN 1125."
My query relates to a social club (likely occupancy characteristic B) with an occupant capactity of 300. The final exit door is fitted with an electric lock which releases on supply failure. There is also a green breakglass unit fitted adjacent. I assume that the panic exit device referred to simply overrides the electric lock mechanism. This has become a bit of a hot potatoe as Council will not issue Entertainment Licence until it can be confirmed that the arrangement complies (although they do not say to what standard it must comply). I would obviously prefer the eod override but I have no wish to cause the Club expense that they can ill-afford.
Regards,
Lyle Dunn

Offline Davo

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Re: Electronic Lock on final Exit
« Reply #1 on: December 17, 2010, 11:06:50 AM »
lyle

Ask them the exact standard.

From what you say it sounds alright, I presume other exits available?

davo

Offline SeaBass

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Re: Electronic Lock on final Exit
« Reply #2 on: December 17, 2010, 12:33:43 PM »
BS 7273 covers the operation of electrical locks on fire exits and their interfacing with fire detection and alarm systems. 

The electric locks need to automatically unlock in the event of a fire alarm activation so that the anti-panic door furniture can be operated as designed, with a single action.

The green BGU is a safety fall back to ensure that the doors can be opened in the event of a system fault. It is not there as a primary means of unlocking and opening the doors.

I hope this helps, let me know if you need more on this topic.


Offline nearlythere

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Re: Electronic Lock on final Exit
« Reply #3 on: December 17, 2010, 01:25:50 PM »
Lyle
BS7273 also says :-
6.1 The user or purchaser of the system (or an appointed
representative of these parties, such as a consultant) should ensure
that, to the extent appropriate, there is consultation, during or prior to
the design of the actuation arrangements, with all relevant interested
parties, particularly the authority responsible for enforcing fire safety
legislation (e.g. the building control body, fire and rescue authority,
local authority, or Health and Safety Executive).


Therefore EH, which enforces fire safety in places of entertainment under The Local Government (Miscellaneous Provisions) (Northern Ireland) Order 1995, should be much more specific of what it wants and to what standard.
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Offline lyledunn

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Re: Electronic Lock on final Exit
« Reply #4 on: December 17, 2010, 07:31:26 PM »
Thanks guys,
I have just got a slap on the back of the head from my good lady who just happened to be looking over my shoulder when I opened this reply. Forget years of electrical engineering expertise, absolutely meaningless when you add a superfluous "e" to potato! Ouch!
Any way, have you any idea why BS9999 does not refer to BS7273?
I have taken your advice and have asked to which standard they would require the system to comply. I had a wee look at 7273 and found this;
Often, enforcing authorities/bodies will not permit use of electronically secured doors or powered sliding doors on means of escape in certain premises in which the doors will be used by a substantial number of members of the public (see Annex A), or in certain premises that need a licence, including bars and places of public entertainment. Reluctance to accept securing of doors or powered operation of doors is based on lack of familiarity with the building, and with the use of manual release controls, by members of the public, in conjunction with the delay in operation of manual call points that has been known to occur in the event of a fire in buildings of this type.
I have to accept that contention. Folk can be pretty stupid at the best of times, those perhaps unfamiliar with the building and, dare I say it, labouring under the influence of some intoxicating liquid may be even in a category worse than stupid.
I am sure that I have seen these locks with a simple mechanical override??
Regards,
Lyle Dunn

Offline colin todd

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Re: Electronic Lock on final Exit
« Reply #5 on: December 17, 2010, 11:05:04 PM »
The failure of BS 9999 to mention BS 7273-4 is just one of many errors in this badly written and ill-conceived standard. It is a well recognized oversight, since those responsible for the code were consulted on the contents of BS 7273-4. A number of building control authorities in NI are aware of 7273-4 and call for compliance with it. And not before time too!
Colin Todd, C S Todd & Associates

Offline AnthonyB

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Re: Electronic Lock on final Exit
« Reply #6 on: December 17, 2010, 11:19:04 PM »
The primary advantage of a panic bolt over a mag lock with all the fail-safes is that the panic bolt is anti-panic at all times (once the night chains are off!)without a need for the fire alarm to sound. A green break glass point is not panic proof and in a panic mass evac and crushing (Station Night Club, Stardust)the door will not open automatically and the chances of someone being able to see & use the break glass is remote, that's if they even know what it is and don't assume the door is locked.

Also is the door lock is electromechanical as oppose to electromagnetic there is a greater risk of failure, particular in panic if the door is compressed and these locks are frowned upon in the DCLG Guide as not being acceptable on means of escape (you may be able to risk assess it through for smaller numbers of persons, who are also familiar with the persons, but possibly not here).
Anthony Buck
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Offline lyledunn

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Re: Electronic Lock on final Exit
« Reply #7 on: December 18, 2010, 12:19:15 AM »
You dont mince your words Colin! I think my copy of BS9999 is for the bin!
With respect to my little situation, I have to admit not being able to find any specific wording in 7273 (other than the comment quoted) as to why the existing system would fail to meet the standard.
Regards,
lyle Dunn

Offline colin todd

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Re: Electronic Lock on final Exit
« Reply #8 on: December 18, 2010, 11:03:50 AM »
Lyle, They are probably not asking about compliance of two forms of locking (panic bar plus maglock). This arrangement will be obvious to them. Two forms of locking is normally frowned upon, I have to say. Also, people usually dont like e-locks on ents premises. However, in NI, it is not uncommon to find e-locks on ents premises. I think I know exactly what they are asking about in terms of compliance. As I noted in the earlier post, the authorities in NI are more attuned to BS 7273-4 and the difficulties for many systems to comply than we English(!!).  If e-locks are used in ents premises, the interface with the fire alarm system should be Cat A (as defined in the BS).  This means that it must fail safe in the event of a fire alarm system fault, including total power down of the system. This can be difficult to achieve with most addressable systems, and the trade have ignored the recommendation. They bleet about it, rather than design equipment and instllations that comply. They are probably quite rightly asking you whether the arrangement will meet Cat A. Hope this helps.
Colin Todd, C S Todd & Associates

Offline graz

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Re: Electronic Lock on final Exit
« Reply #9 on: December 19, 2010, 08:51:08 AM »
I believe that you can get push bar devices with the electronic over ride built in.
Therefore it still acts as a panic device and does not require the operation of a green or red BGCP.
Hope this is helpful.
gamekeeper turned poacher

Offline nearlythere

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Re: Electronic Lock on final Exit
« Reply #10 on: December 19, 2010, 09:45:54 PM »
I believe that you can get push bar devices with the electronic over ride built in.
Therefore it still acts as a panic device and does not require the operation of a green or red BGCP.
Hope this is helpful.
Anyone know where something like this can be sourced?
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Offline mr angry

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Re: Electronic Lock on final Exit
« Reply #11 on: December 19, 2010, 11:58:34 PM »
I believe that you can get push bar devices with the electronic over ride built in.
Therefore it still acts as a panic device and does not require the operation of a green or red BGCP.
Hope this is helpful.
Anyone know where something like this can be sourced?


http://www.magneticlockkits.com/proddetail.asp?prod=KIT-PUSHBAR36

I understand from speaking with an installer that these devices do not stand up well to heavy use.

Offline kurnal

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Re: Electronic Lock on final Exit
« Reply #12 on: December 20, 2010, 07:40:29 AM »
A google search on panic bars and magnetic locks and microswitches comes up with a number of similar products.
As CT pointed out none of them mention BS7273 part 4.
The use of micro switches in these things is a little worrying, not the most reliable or robust of devices. In some buildings such as workplaces this may not be too much of a problem - you may not even connect the lock to the fire alarm system so the conventional green emergency over ride box would be a reasonable compensation, though why bother witht he panic bar?
But in assembly buildings and public buildings there is no option so BS7273 part 4 must be considered.
« Last Edit: December 20, 2010, 07:42:29 AM by kurnal »

Offline SeaBass

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Re: Electronic Lock on final Exit
« Reply #13 on: December 20, 2010, 07:54:57 AM »
I've come across push bars with built in electrical connections twice in the past. They appeared to be fairly robust in that there were no electro-mechanical failures, but they didn't always release the locks.  This was because the electrical actuation was via proximity switches fitted into each bar and there was a slight delay (no more than a second) between the operation of the proximity switches and the locks releasing. This resulted in people pushing against the doors before the catches had been released which, because of the side ways pressure applied to the catches, prevented them from releasing, effectively preventing the doors from opening until the pressure, which was applied by people trying to open the door,  was released.   

Offline nearlythere

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Re: Electronic Lock on final Exit
« Reply #14 on: December 20, 2010, 08:18:38 AM »
Presumably we are looking for green boxs at doors  with hold closed devices so it can be released manually in the event of the FA not sounding.
In the case of a PPA, or places of similar volumes of people, should we consider the provision of an additional green box positioned well away from the door for use by staff?
If the theory is that a crowd pushing at a door which is held closed fails to have the presence of mind or don't know to oerate the GB, it would be unlikely that a member of staff would be able to get through to do so. Therefore a GB a distance away would be beneficial.
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