Author Topic: Slow to Silence  (Read 5781 times)

Offline Gasmeter

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Slow to Silence
« on: August 06, 2008, 09:38:22 AM »
This may be a really stupid question, but I don't have any alarm technical background so please be kind.  We have a 4 loop Morley system in a large old mill type building, the system has had a new panel fitted (last year) and various upgrades over the years.  The problem is that when the staff do their weekly test the system takes around a full minute to silence, by which time people are starting to evacuate, is this normal? Can it be fixed? Thanks for any advice.

Offline Wiz

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Slow to Silence
« Reply #1 on: August 06, 2008, 10:19:06 AM »
I have very little knowledge of Morley control equipment, but this problem seems very strange. I've never seen anything like it (a whole minute!) with other control equipment. Maybe someone who has more experience of Morley can shed more light on it but I suspect there is more to it than just the panel type.
I wonder if the new panel has been 'interfaced' somehow to the old equipment (instead of being directly connected to it) and the interface is introducing the delay? Or is it something to do with your alarm sounders being loop-powered?

The questions I would ask you (to try and work out what is going on) are:

1) How long after physically operating an MCP is it before a fire condition is indicated on the control panel?

2) How long after the fire condition is indicated on the control panel is it before alarm sounders operate?

3) When alarm sounders operate do they do so all at the same time? (or do they seem to begin to sound one after the other?)

4) When the alarm/sounder silence button is pressed how long is it before all the sounders stop sounding?

Offline Benzerari

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Slow to Silence
« Reply #2 on: August 06, 2008, 12:30:52 PM »
Quote from: Gasmeter
This may be a really stupid question, but I don't have any alarm technical background so please be kind.  We have a 4 loop Morley system in a large old mill type building, the system has had a new panel fitted (last year) and various upgrades over the years.  The problem is that when the staff do their weekly test the system takes around a full minute to silence, by which time people are starting to evacuate, is this normal? Can it be fixed? Thanks for any advice.
This could happen in a big system (I mean big load), where probably extra conventional sounders are fitted, the system takes longer time to silence than a smaller system, in my understanding this can happen to any big system...

Offline Benzerari

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Slow to Silence
« Reply #3 on: August 06, 2008, 12:33:09 PM »
The other issue with morley panel is, the same silence button is used to resound again if pressed for the second time, so make sure the bell tester guy is not trying to press on silence button several times to stop it quickly... in fact he is resounding it this is just my guess

Offline Gasmeter

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« Reply #4 on: August 06, 2008, 02:19:51 PM »
Many thanks for your help, I suspect that the guy who does the test is repeatedly hitting the silence button.  If not I'll do as suggested and time the events.

Graeme

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Slow to Silence
« Reply #5 on: August 06, 2008, 08:13:42 PM »
loop powered sounders on addressable systems i.e Apollo ones if not group configured have to all switch on individually and then switch off individually.

It is not unusual to have a delay from pressing the silence button to when the last sounder stops. The bigger the system the bigger the delay but a minute is excessive.

are you sure that your staff are not exagerating?

Offline Benzerari

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« Reply #6 on: August 06, 2008, 10:58:00 PM »
Quote from: Graeme
but a minute is excessive.

are you sure that your staff are not exagerating ?
I would agree with Grame about this bit, the only system takes that longer time is Radio system 5000 of EMS, wave signals are in general slower then the hard wired ones. but in abscence of any other effects and issues...

Offline Gasmeter

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Slow to Silence
« Reply #7 on: August 08, 2008, 08:14:21 AM »
They do the test on Wednesday afternoons, I'm going to attend, see what they're doing and time it.  I'll let you know what happens.  As far as I know the sounders are loop powered, the devices are labeled as Eircom, but I think they're actually Apollo.

Offline Allen Higginson

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Slow to Silence
« Reply #8 on: August 08, 2008, 08:46:09 AM »
Quote from: Gasmeter
They do the test on Wednesday afternoons, I'm going to attend, see what they're doing and time it.  I'll let you know what happens.  As far as I know the sounders are loop powered, the devices are labeled as Eircom, but I think they're actually Apollo.
They will be - eircom is Atlas who were Atlas Communications before eircom previously took them over before going back to Atlas again.

Offline Wiz

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Slow to Silence
« Reply #9 on: August 08, 2008, 08:52:40 AM »
Gasmeter, I wondered in my original answer if the sounders were loop-powered. As Graeme stated above, in the basic operation function of these sort of devices, the system needs to turn them on individually and turn them off individually.
Particularly on multi-loop systems and/or heavily loaded loops it can seem a long time after sending the control signal (e.g. sounder silence) before the last sounder reacts.
However, a minute seems far too long unless there is a further issue with the way the control panel sends it control signals.
It is good that you are going to check this 'problem' out yourself because you will be able to experience and take note of all the relevant information required to be able to properly assess this problem. (I have personal experience of supposed 'faults' being wildly exaggerated. Some reported faults even defied the laws of physics"!)
Again, as Graham mentioned, some sounders and control equipment have a facility known as group addressing that will be able to turn on and turn off all loop powered sounders to one control panel signal. This might be what you need to resolve the 'problem'

Offline Benzerari

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Slow to Silence
« Reply #10 on: August 08, 2008, 10:54:06 AM »
Quote from: Wiz
Gasmeter, I wondered in my original answer if the sounders were loop-powered. As Graeme stated above, in the basic operation function of these sort of devices, the system needs to turn them on individually and turn them off individually.
Particularly on multi-loop systems and/or heavily loaded loops it can seem a long time before sending the control signal (e.g. sounder silence) before the last sounder reacts.
However, a minute seems far too long unless there is a further issue with the way the control panel sends it control signals.
It is good that you are going to check this 'problem' out yourself because you will be able to experience and take note of all the relevant information required to be able to properly assess this problem. (I have personal experience of supposed 'faults' being wildly exaggerated. Some reported faults even defied the laws of physics"!)
Again, as Graham mentioned, some sounders and control equipment have a facility known as group addressing that will be able to turn on and turn off all loop powered sounders to one control panel signal. This might be what you need to resolve the 'problem'
Yes indeed grouping is another issue used to set some sounders with delay, this reminded me some funny case we had one day with Advanced MX4000 panel, the managers them selves complaint of not hearing alarms during bell test, in fact the bell tester guy used to silence them so quick as long as he heard the closest sounder to him going off, we sets a delay by grouping the sounders in the manger’s floor with 10 seconds delay...

One day the managers them selves complaint of alarm going off for quite longer time, it disturbs their meeting…, they instructed us to set the system back to normal (with no alarm delay) obviously we keep charging them of what so ever they ask...