Electro Magnetic door release

[Graeme]

That would be the better solution,but it's not always possible on some types of door.

[messy]

What is the position with maglocked final exit doors in secure or semi-secure locations? (such as Resi care -esp EMI, Mental health units and Prison/Police establishments)

Presumably they can be fitted without a green BGR??

[wee brian]

They have very strict standards of supervision and management to allow for the restrictions on escape routes.

This isn't really viable in anything other than a place of lawful detention.

[Bill J]

Question:

As I understand it there are 2 reasons why A sounder circuit Cannot be used.

1) if someone silences the sounders, then the doors relock, or in the case of doors held open by Magnets, are held open again.

2) failure of a sounder circuit means failure of the door release.

Would it be acceptable to operate the door through a hand reset relay, which would mean that silencing the bells would not relock or "hold open" the doors.

This would have the benefit of controlling the doors over a monitored circuit, (sounders) which means a failure is likely to get attention, rather than an unmonitored (Change-over contact) which may fail.

Just a question, but would really appreciate constructive views.

Bill

[Graeme]

Bill

Magnets should be on a fail safe connection.That means if the cable is damaged or  burned through the magnet de-energises.If the relay failed the magnet would also release as it is inverted.
If taken off a sounder circuit and the line develops a fault,the magnet will stay energised and will not release when the sounders go.

Don't grasp what you mean about a hand set relay.

your points 1 and 2 are also correct reasons why not to.

[colin todd]

Graeme, he means a latching relay I think.

[Graeme]

Thanks Colin.

If this is the case Bill a latching relay would keep the sounders on until the reset button was pressed.

[Bill J]

Hi,

The relay is a latching relay with a manual release, connected to the sounder circuit, the idea being that the sounder circuit will operate as normal, but the relay will on the first activation of the sounder circuit, release the doors, but will not relock until someone has physically visited the doors and positively reset the relay. This is completely different from resetting the panel or silencing the sounders.

I am looking at a number of old buildings in Central London, and running cables from the panel to doors is expensive and aesthetically unacceptable, so i am trying to find an acceptable means of operating.

I am not keen on Dorgards, (which also still hold open when the FA panel shows fault!) and would like to find alternative (But Safe and acceptable) means of door holding, and door releasing.

Therefore a latching relay would allow the doors to be released without them being locked/held open when the sounders are silenced.

Faults on the system which affect the operation of the doors would be monitored, but would not automatically release the doors.

Are there times that you would consider this acceptable. The Alternatives are Dorgard units, or persistent tenants using Fire Extinguishers as wedges.

Thanks

[Graeme]

You are still looking to use sounder circuits which for reasons mentioned before should not be considered.
I know now what you are describing

i.e the sounders trip a relay at each door which would have a reset button on them which would have to be physically pressed to re-energise the magnet.

If you have a lot of magnets,these would have to be done individually every time they were released.

Short answer is no beacuse you are using a sounder circuit.

The way you are describing will still need cables form the sounder to the magnet relay. 240v supply to the psu and output from the psu to through the relay and out to the magnet.

From the panel will require(depending on rating of aux output) one cable to the first door and to next etc.The only current draw will be from the energised relays for the magnets,so the output from panel should support a few.
Also needed would be psu supply and output to magnet.

For Dorguards i'm with you on them but a magnet on a fire system would stay energised if the panel had a fault,unless you went through the fault relay in panel.
This would mean that the doors would close if you got a zone fault etc.
The fire relay is normally used for this as it is non-silenceable.

[Bill J]

Thanks Graeme,

Its not that I want to cut corners, the difficulty I have is that the client will not have disruption to his (very nice) reception areas, which are in some cases listed, and in many cases are crown premises, so they do what they feel anyway.

I am aware of LFEPA Fire Safety Guidance note 48, which is relatively useful, but is there a clause in BS5839 or Part B, or somewhere which I can use regarding NOT using sounder circuits, or stating that the doors must release automatically when the Fire Alarm system is indicating a fault?

The Final possibility is the installation of a mini detection system, on either side of the door, purely to control the door, and releasing the door if any faults are present, this is an option, but would not then be linked to the Fire Alarm system, so the doors would need manually testing once per week, the building would not benefit from the additional detection which would be installed for the fire doors, and there would be no alarm to indicate that there is smoke in the area.

Thanks for any help.

[Graeme]

Hi Bill

The mini detection idea would need a detector from the fire system nearby or like you say if there was smoke the doors would close and nobody would be any the wiser.
Mr Todd is the best person to ask about relaxations in BS5839-1.I,m not aware of any on this matter.
Not sure that if your customer was hell bent on the sounders idea that you could list it as a variation as these need to be justified for certain reasons not cosmetically.

I know exactly where you are coming from with customers who have nicely decorated buildings and want miracles.

ever considered wire free?

[colin todd]

or I/O units if the system is addressable.

[Graeme]

never done it that way.
would you use the input to monitor the fault relay in the psu?
is that required to work fail safe or by the fact the interface and cable on the loop is monitored by the panel anyway?

[colin todd]

The cable to the I/O unit is monitored and powered by the AFD system. If you wanted to be purist and shut the doors on fire alarm fault you would need to operate the relay on fire alarm fault though. Personally, I think that this is OTT, but some guides ask for it. This will all be resolved as and when BSI produce a new CoP on this subject as BS 7273-4.

[Graeme]

Thanks Colin.
Will the new cop ask for doors closed on fault condition and is that a general fault condition or specific to the i/o unit?
If it's a general fault i agree with being ott.