Audible activated door release units

[Gary Howe]

Does anyone have any knowledge of door release units activated by fire alarm sounders?

I have a property with linked smoke detectors (small office) which needs the fire doors opening onto the escape staircase to be held open during the day (at the moment they are being held open with wooden wedges!!!!!!!!!).

I am looking at this as a possible alternative to hard wiring magnetic door release units from the type 'M' fire alarm system installed (separate to the detectors mentioned above).

I have seen adverts for them in the IFE/FPA journal however I do not know of their features, functions and benefits and most important of all their disadvantages.

Has anyone specified them? And if so what do you think?

Any advice would be welcomed.

Regards


Gary

[John Webb]

Dear Gary,
Look at the 'Dorguard' topic on this site which is discussing these devices already.

[kurnal]

These devices can be an ideal solution where door wedges are in use but through your risk assessment you should first  seek to prove that it is not reasonably practicable to improve the fire alarm to an L3 (or even L5) standard and provide magnetic releases wired to the fire alarm.
It is undesirable to have two seperate fire alarm systems in a building- two different sounds, two different sound pressure levels and different audibility throughout the building.
Normally the benchmark standard  an office is for a manual system unless the smoke detectors have been used to compensate for some other shortcoming.

Before installing the dorgard type units it is essential to check the units will operate from both smoke detectors and manual sounders. They also do a radio linked system if audibility is a problem- but the cost of this more or less erodes the cost benefit over conventional magnetic releases.

Sometimes they can struggle with heavy doors, powerful or maladjusted closers, uneven floors or some floor coverings- an optional floor plate is usually provided for use in these situations.

But they will never be as resilient as a wired in system, their biggest weakness is that they may fail to work if the local sounder fails. But a thousand times better than a wedge.

[Chris Houston]

Gary,

They are better than a wedge, but both seem unacceptable in the circumstances.  In my opinoin, fire doors need to be closed, or held open by something that will close them in the event of a fire without human intervention.  Smoke detection around the doors must be a minimum.

I would also have concearns about their reliability, are they fail safe, do they snag on carpets, do things get put in the way of the door, is the fire alarm loud enough in the area.  

In my opinion, there are too many variables to go wrong.

[Brian Catton]

Gary,

If your risk assessment confirms that linked smoke detection is adequate I would not recommend any additional expenditure. I would ask the question, why do the doors have to be open during the day? When I know the answer to this question I could advise you further!!!!!

[Gary Howe]

Brian,

Yes my FRA does confirm that the linked smoke detectors are adequate, the doors are only open during the day as there is no real ventilation to this 4 storey building (converted mid terrace georgian house in central London) and the (single) staircase and doors leading off it are in constant use. In order for the building to be used (practically speaking) on a day to day basis, the doors need to be maintained in the open position, otherwise it would uncomfortable and inpractical for the tenants to occupy the building.

So my view, in order to find a pragmatic solution and to balance out fire safety is to have the doors held open by some form of automatic closuer device.

Does this help?

[Paul]

Gary,

As others have said, the door retainers we are discussing do have limitations, although under certain circumstances are worth fitting.  As you say this is an office facility served by a single stair.  If you take adequate messures to ensure the door retainers will indeed release upon activation of the alarm sounding then I see no reason why this is not a viable option.  I would work on the fact that if you do not fit them, the doors in question will be wedged anyway.

I have believe that weekly testing of this release mechanism must also be carried out and documented as part of the overall fire precations testing.  In doing so any issues with operation are managed early on.

For what its worth.
P

[Graeme]

open a window

[Gary Howe]

Open a window, now why did I not think of that!!!!!!!!!!!!!, I can assume you have never been in an office (without air con) in the middle of summer (when the temp was 29oC), which leads onto a busy London street, the combination of car fumes and warm air blowing through the windows is not highly desirable.

Next sensible suggestion please!

[Graeme]

It was a joke Gary...

[messy]

Has anyone any views about dorgards being used on single staircase buildings such as being described here?

Personally, as had been said, with safeguards I see no problems. But would the Fire Brigade agree to a MDH or dorgard on such an important escape route?

[Gary Howe]

Graeme, your Scottish sense of humour was lost on me for the moment there, perhaps you are not used to the warm weather in your part of the world?

[Graeme]

It's like the Med up here Gary.

[Chris Houston]

Graeme, your Scottish sense of humour was lost on me for the moment there, perhaps you are not used to the warm weather in your part of the world?

Don't worry chaps, I will ensure that Gary is suitably punished for his lack of understanding of the Scottish.