Author Topic: Silencing of Automatic Fire Alarms  (Read 4727 times)

Offline BB

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Silencing of Automatic Fire Alarms
« on: September 13, 2008, 07:21:43 PM »
Hi All

Question for all you technical boffins out there on a Saturday night.

Premises in question has installed a fully addressable automatic fire alarm which has separate zones.

The Fire Service have responded to fire in premises, however upon arrival and having carried out a through search of the premises that cannot find a fire either in the premises or the effected zone.

The OIC gets the key holder to silence the alarm but does not reset it leaving it with the key holder who it not overly familiar with the system and therefore leaves zone A silenced but not reset.

If another head in that zone picks up on particles of smoke will the fire alarm actuate in that zone again.

My feeling is that it will. Had a look through BS5839 but cannot find a definitive answer but gut feeling tells it would.

Any further guidance would be appreciated.
Save a little money each month and at the end of the year you'll be surprised at how little you have :)

Offline Benzerari

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Silencing of Automatic Fire Alarms
« Reply #1 on: September 13, 2008, 11:03:21 PM »
Quote from: BB
Hi All

Question for all you technical boffins out there on a Saturday night.

Premises in question has installed a fully addressable automatic fire alarm which has separate zones.

The Fire Service have responded to fire in premises, however upon arrival and having carried out a through search of the premises that cannot find a fire either in the premises or the effected zone.

The OIC gets the key holder to silence the alarm but does not reset it leaving it with the key holder who it not overly familiar with the system and therefore leaves zone A silenced but not reset.

If another head in that zone picks up on particles of smoke will the fire alarm actuate in that zone again.

My feeling is that it will. Had a look through BS5839 but cannot find a definitive answer but gut feeling tells it would.

Any further guidance would be appreciated.
Indeed it would, If the panel has been silenced and not reset due to device was in fire and did not clear out fire condition (due to broken glass or to much smoke in the chamber of a head...), this wouldn't prevent any other device to trigger and set alarm off in case of fire!

Regarding the device that wouldn't reset, apart from broken glass, too much smoke in the chamber...etc, the worst scenario could be caused from the PCB, I have seen once such incident... etc.

Call fire alarm engineer in charge of the system :)

Offline Allen Higginson

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Silencing of Automatic Fire Alarms
« Reply #2 on: September 14, 2008, 12:39:25 AM »
Quote from: Benzerari
Quote from: BB
Hi All

Question for all you technical boffins out there on a Saturday night.

Premises in question has installed a fully addressable automatic fire alarm which has separate zones.

The Fire Service have responded to fire in premises, however upon arrival and having carried out a through search of the premises that cannot find a fire either in the premises or the effected zone.

The OIC gets the key holder to silence the alarm but does not reset it leaving it with the key holder who it not overly familiar with the system and therefore leaves zone A silenced but not reset.

If another head in that zone picks up on particles of smoke will the fire alarm actuate in that zone again.

My feeling is that it will. Had a look through BS5839 but cannot find a definitive answer but gut feeling tells it would.

Any further guidance would be appreciated.
Indeed it would, If the panel has been silenced and not reset due to device was in fire and did not clear out fire condition (due to broken glass or to much smoke in the chamber of a head...), this wouldn't prevent any other device to trigger and set alarm off in case of fire!

Regarding the device that wouldn't reset, apart from broken glass, too much smoke in the chamber...etc, the worst scenario could be caused from the PCB, I have seen once such incident... etc.

Call fire alarm engineer in charge of the system :)
Not strictly true Benz in the case of conventional alarm systems or addressable systems that are configured to resound in the event of fire on another zone only (this option is available on the MINERVA ie - resound for another device or resound in another zone).

Offline John Dragon

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Silencing of Automatic Fire Alarms
« Reply #3 on: September 14, 2008, 08:53:45 AM »
Buzz is correct, usually an addressable system is set not to resound when another device in the same zone activates.
If we believe that a building has the potential for the end user to leave the system in fire condition (i.e. just press "silence alarms"and not "reset" after an activation) we will then enable "another device in same zone to resound alarm". e.g. HMOs.

Offline BB

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Silencing of Automatic Fire Alarms
« Reply #4 on: September 14, 2008, 09:16:21 PM »
Gents thanks for the information. pretty much as i thought
Save a little money each month and at the end of the year you'll be surprised at how little you have :)

Offline Benzerari

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Silencing of Automatic Fire Alarms
« Reply #5 on: September 14, 2008, 10:58:25 PM »
Quote from: Buzzard905
Quote from: Benzerari
Quote from: BB
Hi All

Question for all you technical boffins out there on a Saturday night.

Premises in question has installed a fully addressable automatic fire alarm which has separate zones.

The Fire Service have responded to fire in premises, however upon arrival and having carried out a through search of the premises that cannot find a fire either in the premises or the effected zone.

The OIC gets the key holder to silence the alarm but does not reset it leaving it with the key holder who it not overly familiar with the system and therefore leaves zone A silenced but not reset.

If another head in that zone picks up on particles of smoke will the fire alarm actuate in that zone again.

My feeling is that it will. Had a look through BS5839 but cannot find a definitive answer but gut feeling tells it would.

Any further guidance would be appreciated.
Indeed it would, If the panel has been silenced and not reset due to device was in fire and did not clear out fire condition (due to broken glass or to much smoke in the chamber of a head...), this wouldn't prevent any other device to trigger and set alarm off in case of fire!

Regarding the device that wouldn't reset, apart from broken glass, too much smoke in the chamber...etc, the worst scenario could be caused from the PCB, I have seen once such incident... etc.

Call fire alarm engineer in charge of the system :)
Not strictly true Benz in the case of conventional alarm systems or addressable systems that are configured to resound in the event of fire on another zone only (this option is available on the MINERVA ie - resound for another device or resound in another zone).
Sorry, I haven't read carefully, it's true in automatic system which is conventional system, according to the title, but not for addressable system, I kept in mind automatic fire alarm system while in fact BB said addressable automatic fire alarm.... in his post…

Conventional system doesn't need in general any configuration except very few makes, and so if you trigger another device in the same zone, where a device in fire condition is been just silenced, any second device would set alarm again, I have tried that myself :)

Offline BB

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Silencing of Automatic Fire Alarms
« Reply #6 on: September 15, 2008, 08:28:14 PM »
Many thanks Benzerari for the clarification. regards BB
Save a little money each month and at the end of the year you'll be surprised at how little you have :)