Green break glass door release boxes

[Wiz]

Wiz, I may be missing the point, but for the most part in multi-occupied buildings the green boxes are on the occupier's side of the door to allow them to access the stairway in the event of an emergency.  Where they are sited alongside final exit doors they are again on the occupier's side.  How does this allow your "scum" to use them to over-ride the system?

Tall Paul,

In this case there are obviously doors leading to an emergency escape staircase from a car park. People are misusing the staircase so electromagnetic locks have been fitted to the door to prevent unauthorised use of the staircase. On a fire alarm condition the locks automatically release to allow the emergency escape staircase to be used.
The argument is that a green BGU (operation of which would also release the door lock) should also be fitted to the car park side of the door in case of an emergency where the fire alarm has not released the door, for whatever reason and ,particularly, if there was a failure of the system to send the release signal. Obviously, such a provision could be abused and people use it to gain access to the staircase when they are not meant to.
I trust this explains the situation which is a very common predicament. Even green BGU's on a side that can be clearly determined as the 'occupiers' side can be misused i.e if the occupants are prisoners or mentally disabled etc. etc.

[afterburner]

Wiz,
your comments regarding prisoners is correct. Where electro magnetic locks are used (of the normal design variety) they are not fitted with green BGU's. Absolute reliance is placed on the deactivation of the magnet by operation of the fire alarm system or any power failure. (this reliance is subject to substantial routine systems checking). The real problems come from the fire alarm system which is really a big electronic key to open the magnetically locked doors. Interference with the fire alarm system is a whole subject on it's own!

[Keith Tarbuck]

Some very interesting comments and thoughts on this subject.

Just for information purposes, one of our Students accommodation sites (Manchester) recently had a Fire Safety Audit conducted by the local Fire and Rescue Service in line with RRO and these devices are not at all liked by the Manchester Fire Service. Main reason is that they are relying on a electric power source to work in conjunction with an alarm system i.e. alarm is activated and the locking door maglock fails?

We have a policy that all doors are tested (black key) same as our MCP test key weekly and during the weekly alarm test all doors are checked to ensure they release.

We have had 3 occasions where the maglock (same door) failed to release during the "emergency release" box test and  failing to release during an alarm test.
 
The door would operate on the normal release push button, each time down to a wiring issue?

We are looking at at changing the door locking system to a good old simple but effective yale lock (outside only) and the push pad release system.

We believe long term this will be more cost effective and safer in the event of an emergency?

Take on board comments regarding security issues, we have this where the students will use stones to wedge doors open (lost swipe or key won't infrom  staff - as they are charged to replace) we have looked at systems that alert if the door has not be closed fully (set your own time delays)

[kurnal]

Keith
By their very nature if power fails magnetic door locks will release. The normal switch breaks the supply to the magent allowing the door to be opened. The green box usually breaks both poles of supply to the magnet  to be absolutely certain  the magnet wll let go, and to cover for any earth faults.  If the green box is not releasing the door then its not wired into the circuit. Is the best answer to wire it correctly rather than get rid of it? Yale locks are also subject to abuse and no more secure than the mag lock in this respect.

I have never heard of a correclty wired mag lock failing to release, whereas electronic keeps are notorious for failure to release especially if the door is not well hung and the keep is under tension.

[Wiz]

Keith,
Following on from Kurnal's comments, it would be very surprising if a correctly wired green bgu should fail to release the fail-safe door lock unless it is incorrectly wired or there is the problem I mentioned previously where the two-wires connected to it are shorting out (wire insulation damaged as it goes through a hole in a metal door frame?).
The green bgu should be wired as a normally closed (opening on operation) switch wired in series with the power supply feeding the magnet (it should preferably the last item in circuit before the magnet).
One serious, but little known, problem with magnetic door lock systems relates to the request to exit button. This button can also be a normally closed switch wired in series (like the green BGU) with the power source to the magnet, but is often, when there is a keypad or card access system also fitted to the door, wired as a normally open switch to a special set of terminals provided on the keypad or card reader for such a switch (I won't go into the reasons  why you might do this unless someone specifically asks me to!). because this sort of switch is normally open it is not fail-safe. When you have such a switch it is imperative that you have the normally closed switch green BGU as a back up to any possible Request To Exit switch failure.
Of course, someone could also incorrectly wire the green BGU as normally open, in parallel, to a normally open RTE switch. If they do such, it will open the door but will now be not fail-safe.

[saddlers]

Thats how i view it too. A red box ie fire callpoint is red becuase it indicates that when activated it will raise the fire alarm.

Sorry I have may not have explained the circumstances in using the "call point" very well. If in addition to the call point there is a sign saying something like "break glass to open door and activate fire alarm" this could be a possible solution. Whilst as pip says it is two functions (signal to panel and back to door) and therefore may not be perfect, it may be a bespoke solution to a particular issue in that it makes people aware that the alarm will activate if they use the override. Not perfect, but a lot better in my mind than risking arson by unauthorised people gaining access.

As I say it is not a solution I would apply everywhere, but I would definitely consider it in the correct scenario.

[jokar]

For all those interested BS 7273 part 4 has now been issued.