Fault Monitoring of cable from Fire Panel to ARC transmission eqpt

[Guest1]

Most fire alarm designers who are familiar with BS 5839~1:2002 will opt for a BT RedCARE monitored signal for their fire system instead of a standard digicom, mainly for the issues about having continuous fault monitoring of the telephone line between the transmission equipment and the ARC and the fact that most intruder alarm digicom's don't comply to BS 5839~1:2002. There are still a lot of fire alarm engineers who don't understand the need to monitor this link but the numbers of those who do are rapidly rising.

What seems to be lacking throughout the industry is the monitoring of the signal from the fire control panel to the transmission equipment. I have always found the transmission equipment to be in a separate enclosure and, according to item 9 of 12.2.1a) of BS 5839~1:2002, this wiring should be monitored for a short or open circuit.

My experience is that most systems, including those designed & commissioned by specialist fire companies, simply have a 2-core signal wire from the unmonitored changeover contacts in the panel to the transmission equipment. This is usually because the manufacturer has not provided any monitored contacts, though a very small number do. The main question I would be interested to hear any answer on is does any one bother ensuring that this signal is monitored, especially when a monitored output is available?

On the same vein, does anyone monitor the fault output contacts of their transmission equipment so that such a fault is indicated on the fire system CEI? EN54-4 requires that a fault, such as the failure of the battery when the mains supply is still healthy, should be indicated but, again, I never come across anyone who ensures that a fault of the transmission unit or its separate PSU is monitored at the CEI.

[Allen Higginson]

Good points.Although I would always monitor PSU's where possible (it's much easier on an addressable system) I'm proboably as guilty as most in the non-monitoring of the two core to the comms.Again,it's much easier in the new panels so borne in mind from now on!

[Guest1]

I agree, it is much easier with an addressabel system. The problem I see is that most manufacturers still don't have monitored output contacts in their control panels ....

I have quizzed several manufacturers on this point and most usually say to use use the monitord contacts off a loop interface or a spare alarm circuit in the control panel to energise a relay in the transmission equipment. I am extremely unhappy with the first idea as a fault on the loop card of the loop of said interface means you lose the ARC signal for the entire system.

The second idea seems to be the only other acceptable way of achieving this but a lot of fire officers and designers want the signal to be be taken off on a panel "reset" rather than a panel "silence". It also depend on a spare alarm circuit being available to use soley to energise a mini-relay mounted within the transmission equipment. This is usually not a problem with an addressable system but is for most makes of conventional panel - a rare exception is a 4 or 8 zone Gent Xenex panel which has the same number of alarm circuits as zone circuits.

For the few manufacturers that do have monitored output contacts in their panels, e.g. the Ziton ZP3 analogue addressable panel, this still doesn't provide fault monitoring of all parts of the transmission equipment and its power supply (if separate) ....... ()

[colin todd]

It is done. Otherwise a variation from 5839 has to be agreed.

[Guest1]

Colin, when you say "it is done", do you mean that most systems you are involved provide monitoring of both the signal cable and the faults outputs of the transmission equipment (inc. the PSU)?

In theory, these two factors would either occur or, as you stated, be a variation. In practice, I have very rarely found this to be the case. Most designers don't want to know once they have issued their tender documents or once the contract is placed with the installer and, in many of the cases I'm aware of, the first time the commissioning engineer gets a sniff of the job is when he is told a day or two in advance that the job is to be done - explaining to the installer that the designer has missed a vital part of the system and having to list it as a variation when the designer is not interested usually leads to future work being awarded to someone else.

I don't know how much verificiation work you do on other peoples systems where you have had no prior involvement, but what percentage do actually have a fully compliant signal to the transmission equipment and also fault monitoring as described above? Also on the same vein, if either is lacking and has not been agreed as a variation by the time of project handover, can such a non-compliance be accepted as a variation, say, 18 months later?

[Allen Higginson]

The Haes excel range of conventional panels have both monitored fire and fault outputs.These can be configured as sounder outputs if required.

[Guest1]

Haven't seen any Haes panels before but like the idea of monitored fault output contactsas well.

What about monitored fault inputs on the panel as standard? I'd anticipate that this sort of function is better suited to an addressable panel where a set of monitored 'fault inpit' terminals in the control panel can be labeled to suit the equipment being monitored. Is there such a beast?

[Graeme]

Haven't seen any Haes panels before but like the idea of monitored fault output contactsas well.

What about monitored fault inputs on the panel as standard? I'd anticipate that this sort of function is better suited to an addressable panel where a set of monitored 'fault inpit' terminals in the control panel can be labeled to suit the equipment being monitored. Is there such a beast?

Yes-Aritech FP1200 and 2000 series.

[Allen Higginson]

As you say it can be done with any addressable system but it can also be done using a spare zone input.Just place the EOL through the closed fault contact.Then when a fault occurs you get a fault up on the zone on the panel.Or have I got the wrong end of the stick??

[Guest1]

Buzzard905, yes, you've got the correct end of the stick! A spare zone circuit will work as will a spare alarm circuit - in many ways, an alarm circuit is better as the transmission equipment is part of the external alarm 'critical signal path'. In my experience, it's just a matter of ensuring a suitable label is fitted on the facia of the panel so that a maintenance engineer knows what to look for.

Graeme, I tried a search for Aritech and keep on getting transfered to GE who appear to have aquired them along with several other firms recently. Are the panels mentioned conventional or addressable? If the latter, is there a facility to change the label of the monitired fault input?

[Graeme]

http://www.geindustrial.com/ge-interlogix/emea/aritech/fire/fp2000.htm

It's a/a panel with internal supervised inputs and outputs which are programmable through the cause and effects table.You can give each input and ouput text description.

G.E.C Interlogix bought Aritech but they still trade as Aritech under G.E.C

[Guest1]

Thanks for the link. Will look for it at Fire Expo tomorrow.

[smoke monkey]

Its so simple this....

Wire up the output from the fire panel through a normally closed fire relay in the fire alarm panel and set your signaling unit to send a fire signal when the positive voltage is removed from the fire signaling channel 1.

Then if someone cuts the cable or it goes open circuit due to a cable fault the signaling unit will send a fire signal to the Alarm Receiving Centre.


The problem with common sense is that its not that common.

[David Rooney]

But I thought "monitoring" included for short circuit faults ??

I though all EN54 panels have to have a fire and fault "routing" - ie monitored outputs... Syncros do and they have programmable inputs that can be used for fault inputs....

[Wiz]

I'm pretty sure the BS only recommends monitoring of the link between CIE and alarm transmission device (if not in same enclosure) but without confirming exactly what level of monitoring is required nor if it is the CIE or arc who should be made aware of a problem. This leaves things pretty much open for interpretation.

Whilst we are on the subject of RedCare, may I ask for comments on the monitoring provided beyond the transmission device. I was once told by a BT engineer that it is only the telephone line between the transmission device and the local telephone exchange that is monitored i.e the whole circuit from transmission device to arc is not continuously monitored. Is this true?