Fire alarms signalling connected to an intruder alarm system

[Gary Howe]

As the use of the intruder alarm redcare to send fire signals to a central station is non compliant to the requirements of BS5839 part1:2002, unless of course you put this down as a variation on the design certficate.

As this sort of interconnection is common place, and most people are unaware of the non compliance issue, would not the solution be to always have the Redcare at the fire CIE and get the intruder alarm company to install a cable to the fire panel instead of the other way round.

My question being, how does this affect the intruder standards and the requirements of NACOSS?

Does the requirements of Fire Safety override the requirments of the intruder system, or is there a solution to dovetail them together?

[Guest]

It may not always fail to comply with the BS. It depends on how you configure it. But the answer if you want to be 100% compliant is as you suggest. This will not worry the intruder people.

[Gary Howe]

Colin,

Thank you for your prompt reply, this seems to be an issue that is now cropping up on a regular basis.

[Guest]

Where one system is getting its signalling mechanism piggybacked on another system, it is most important to spell out in the specifications exactly who is going to be responsible for what.
In such circumstances it is likely that three or more service providers are involved, the Intruder system firm, the Fire system firm and the alarm receiving centre (ARC). It gan get very messy and costly when the relationships and responsibilities get confused.
It is widely believed that the Fire services will seek to introduce URNs for FDAs with signalling facilities

[Guest]

....It is widely believed that the Fire services will seek to introduce URNs for FDAs with signalling facilities

Interesting. Can anyone shed light on this proposal?

[Gary Howe]

To outline who is responsible for what is an excellant idea, but at the end of the day the client will more often than not seek the cheapest option, we have to look at this issue from another angle.

The Fire brigades have alreardy started to adopt procdures to prevent uneccesary attendance, or reduced attendance based on the risk of the building, what we need is some form of incentive to make building owners aware of their responsiblities under 5839 pt1: 2002.

The standard clearly outlines what is acceptable as far as false alarms are concerened per annum, but the problem I am finding is this "so what" attitude, if I go over and above the recommeded number of false alarms, then what is going to happen to me?

Well we know the obvious answer is that the fire detection system is now non-compliant to the standard, and public and civil liabilty issues may now arise, but is still does nothing to push the average building occupier to do something about it!!

History has shown us that most current fire safety legislation has arisen from specific fire disasters, and in relation to this subject, the big question is, where is the teeth!

[colin todd]

I'm not sure but, in all seriousness, you have just reminded me that I have an appointment with the dental hygienist in the morning, which I had forgotten all about. So many thanks for that!

[colin todd]

There are various other non-compliances with this arrangement. Battery capacity is one of the most important and is the most readily soluble, but its only one of several.

[colin todd]

There is a list on the NSI website,

[Gary Howe]

When you connect an intruder STU to a fire alarm you have to comply with the following 6 clauses:

 Clause 25.4: recommendations for standby supplies (page 67): all power supply units should have sufficient capacity to maintain the system for 24hrs after which sufficient capacity to provide either an evacuate or alert signal in all zones for at least 30mins.
My response: This means that a standard PSU supplying a intruder RedCare does not comply as it would typically have a 8hr capacity. Also fire alarm PSU’s should comply with EN54-4, intruder PSU’s are not tested to this European standard.

 Clause 12.2.1: fault monitoring (page 22) a fault indication should be given at the control and indicating equipment within 100sec of the occurrence of the following:  

12.1.1 9): a short or open circuit between the control equipment and RedCare STU

My response: This means the cable linking the fire alarm and the intruder RedCare has to be monitored. This in the majority of installations will not happen as the STU is normally a –ve applied system, and any damage/fault to the cable will not be recognised at the fire alarm panel.

12.2.1 b) 1): failure of the main power supply to any part of the system (within 30 min of occurrence)

My response: This means the intruder panel signalling a mains failure back to the fire alarm panel, at the moment if the mains fails at the intruder panel, the fire alarm will not be aware of it.
12.2.1 b) 2): failure of the standby power supply to any part of the system (within 15 min of occurrence)

My response: This means the standby batteries being monitored. If they fail then the fire panel needs to be aware of this fault.

12.2.1 b) 3): failure of the battery charger (within 30 min of occurrence)

My response: This means the internal intruder panel battery-charging unit being monitored. If it fails then the fire panel needs to be aware of this fault.


 Clause 26.2 (page 70): cables, wiring and other interconnections.

My response: This means the wiring between the fire panel and the intruder RedCare being wired in at least standard fire resistance cable e.g. FP200, Firetuff.


Summary: It is a common misconception that by linking the two systems together, you have fully complied with 5839 part 1 (I am afraid not!). The majority of electrical contractors/fire alarm installers claim compliance, when they should not. The only way to fully comply with the standard is to fit the intruder RedCare immediately adjacent to the fire panel this way any wiring between the two is classified as internal panel wiring.

By simply linking the two together in fire proof cable, as you can see from the text above, does not really comply in any shape or form.

If you do want to share a RedCare it is important that a variation is put on the design certificate to inform the client that there are variations away from the code of practice. As long as everyone is aware of the variations, then this could be deemed to be fine. I hope my advice helps.


Best Regards



Gary Howe

[Graeme]

Gary,
      Many thanks on taking time for that very useful reply.It helps a lot to see it laid out in the way you have done it.

Kind Regards

Graeme Millar

[NE-Neil]

The comments about using a EN54 compliant PSU and one of the new 24V Redcare STU's isone that seems to becoming the norm' but the issues about monitoring the the signal cable from the fire panel to the STU and also the fault monitoring of the PSU and the STU still seem to be conveniently ignored by most fire alarm engineers.

One method which I have seen employed recently is to use the usual 2-core cable off a spare alarm circuit in the fire control panel to activate a relay in the STU which in turn sends the signal to the ARC but then the End-Of-Line for that circuit in series with the fault contacts of the STU and the PSU to provide monitoring of the cable, the STU and the PSU.

This seems to comply with all the recomendations and the only negative comment I have got so far is that many folk prefer to have their fire output from the panel to come off auxilary contacts rather than a relay off an alarm circuit. The fact that most fire alarm manufacturers do still not have monitored contacts for their panel auxilary relays means that the alarm circuit method is the only way of achieving this without, say, using a separate loop interface with monitoring output contacts.

Any comments?