The LWF Blog

Fire Safety Engineering for Design – Fire Detection & Alarm Systems – Part 158

November 13, 2023 11:57 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 157, LWF talked about the disadvantages of gas combustion detectors before beginning to look at video smoke detection. In part 158, we continue discussing video smoke detection (VSD).

Video smoke detection is particularly adept at detecting smoke in large open areas where smoke paths cannot be predicted. VSD does not rely on smoke reaching a certain height as with smoke detector heads and is able to provide a much wider coverage per detector.

Designers may opt for a VSD system in areas where the installation of a standard fire detector system could be considered conspicuous or not in keeping with the overall ambience. These systems are also often used in areas where valuable equipment is stored over a large area and it is imperative that a fire is detected quickly.

As this is a software-based fire detection system, the trigger thresholds can be set to work at certain levels depending upon where the detection is to work within a building, in order to minimise false alarms.

There are certain conditions that must be maintained when using VSD systems. Cabling to the system must be carefully considered and protected if they are to continue to operate during a fire situation.

The VSD cameras will need appropriate levels of lighting to work at all times. Some systems are able to work with infrared lighting which would also need to be maintained at all times.

Persons in charge of building maintenance must understand the requirements of the system and the lighting installation, so that any future building development does not compromise the video smoke detection system.

It should be noted that although this blog has concentrated on the use of video smoke detection systems, there are also video flame detection systems and systems which combine the detection of both smoke and flame through CCTV systems.

With all video-based fire detection systems, there are certain advantages over other types of system, namely that the location of the fire can be accurately pin-pointed, that the images and video of the fire can be stored upon alarm trigger meaning that the reason for the fire starting can be investigated, and remote monitoring of the alarm system means that the fire alarm can be verified by personnel, reducing the risk of the Fire Service being summoned to a false alarm.

In part 159 of LWF’s series on fire engineering, we will be considering the siting and space of detectors. 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.

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