The LWF Blog

Fire Engineering Design and Risk Assessment – Fire Alarm Systems – Zoning and Addressable Systems – Part 11.

August 11, 2016 2:58 pm

In our recent blog series for Architects and those who work planning building projects, we have been looking at fire alarm systems and last week, we began to look at zoning. In today’s blog, we will begin by looking at how zoning works with addressable and analogue addressable systems.


When looking at addressable or analogue addressable systems, you should be aware that each detector or call point is given a numerical address code. Each device on the network is wired in a loop arrangement and the amount of detectors on each loop may vary, according to manufacturer recommendations and the length of the loop. One loop can, however, cover more than one detection zone.


BS 5839 Part 1 states that short-circuit isolators should be used between each zone, in order that if a fault occurs in one zone, it will not affect devices in other zones. In the case of an addressable system, the devices can be assigned to separate zones through programming of the control panel.


Considering the area that a single loop can encompass, the maximum should not exceed 10,000m2 and in the case of addressable or analogue addressable fire alarm systems, each detector or manual call point can be shown by the use of an alphanumeric display, which must also be accompanied by a display of the zone in which that point lies.


In order to aid with the identification of where the detector or manual call point lies within the building, it is important to display a diagram or chart of the system beside the control panel. Additionally, BS 5839 Part 1 requires that a plan of the building be displayed and so the use of a ‘mimic diagram’ which shows the layout of the system and building is usually the best option. Of course, some systems may show this information on the control panel itself.


BS 5839 does recognise that in some less complex buildings with smaller systems, there will be no confusion over the location of the alarm or fault and so zonal information is not required.


As you might have noticed, manual call points have been mentioned so far in this text and although they are familiar to many people, a short overview is necessary and will be provided in our next blog.


In the meantime, if you have any questions about this blog, or wish to discuss your own project with one of our fire engineers, please contact us.


Lawrence Webster Forrest has been working with their clients for over 25 years to produce innovative and exciting building projects. If you would like further information on how LWF and fire strategies could assist you, please contact Peter Gyere on 020 8668 8663.



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