The LWF Blog

Fire Safety Engineering for Design – Fire Detection & Alarm Systems – Part 146

August 21, 2023 10:37 am

LWF’s Fire Safety Engineering blog series is written for Architects, building designers and others in the construction industry to highlight and promote discussion on all topics around fire engineering. In part 145, LWF discussed conventional monitored fire detection systems and addressable systems (including analogue addressable). In part 146, we continue to look at addressable systems (including analogue addressable) and detection zoning.

Analogue addressable systems are one of the most commonly installed fire detection and alarm systems. The detectors used relay information to the control and indicating equipment on a constant basis. The information received allows for tweaking of the settings to compensate for high ambient levels of smoke during normal day-to-day use. The adaptability of analogue addressable systems means they are useful in most environments.

Additionally, the control panel of an analogue addressable system is able to monitor the contamination levels of each of the system’s detectors and alert the user when maintenance is required (over and above the regular maintenance schedule required).

It may be that the building in which the fire detection system is installed is used for processes which can lead to false alarms during working hours. Analogue addressable systems can be adapted so they are less sensitive during the daytime/working hours and revert to full sensitivity for overnight hours when the building is unoccupied.

Conventional detector zones and call points can be connected to an analogue system by appropriate interfacing devices.

Detection Zoning

The area protected by a fire alarm system should be divided into detection zones. This means that when a fire detector is activated, the control panel will display unambiguous information about the location of the fire source.

When planning the installation of a fire detection system, consideration should be given to the area to be covered by a zone. It is important to consider factors such as accessibility, size, fire management strategy for the premises and the need for each detection zone to be accessible from the main circulation routes, leading from where the control panel is situated. An addressable fire alarm system is capable of giving very accurate information on the location of a fire source.

In part 147 of LWF’s series on fire engineering, we will look at the formal recommendations for zoning of fire alarm systems as per BS 5839-1. 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 since 1986 to produce innovative and exciting building projects. If you would like further information on how LWF and fire strategies could assist you, please contact the LWF office on 0800 410 1130.

While care has been taken to ensure that information contained in LWF’s publications is true and correct at the time of publication, changes in circumstances after the time of publication may impact on the accuracy of this information.