How many zones are needed?

[Guest JohnWats]

Good morning,

I'm a property managing agent and have received a number of quotes for installing a conventional alarm system in the corridors and stairwells of a modern residential development. However, none of them agree about the number of zones required. I would have thought that there should be one zone per floor and another zone for the stairwell/entrance lobby. Is there any guidance available on this, please?

Cheers

[Tom Sutton]

There is the latest guidance, BS 5839-1:2002+A2:2008 Fire detection and fire alarm systems for buildings. Code of practice for system design, installation, commissioning and maintenance, which covers detection zoning fully and also alarm zoning but it covers quite a few pages, too many to give a resume here. You may be able to view it at your local reference library or you could purchase it, but it doesn't come cheap £ 254.00.

[CWEENG]

In general,

floor area for a single zone should not exceed 2 000 m2

If the total floor area of the building is greater than 300 m2, each zone should be restricted to a single storey / floor.

If the total floor area of the building is less than 300 m2 a zone may cover more than a single storey (mindful of total quantity of devices).

For systems using conventional detection (non addressable), the search distance should not exceed 60 m in distance, so a an additional zone would be required if a search distance is greater.

detectors within any enclosed stairwell, lift shafts or other enclosed flue-like structure should be considered as a separate detection zone.

PS

BS 5839-1:2002+A2:2008 has been superseded now by BS 5839-1:2013 (only minor changes within but they still felt it necessary to bring out a full revamp, ££££££)