The LWF Blog

Fire Safety Engineering for Design – Fire Detection & Alarm Systems – Part 129

April 24, 2023 10:56 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 128, LWF looked at information and wayfinding systems. In part 129, we begin to discuss fire detection and fire alarm systems.

Although fire alarm systems are often considered to be a stand-alone system to warn of fire, increasingly they are being seen in use as part of a fire-engineered design in a building.

Their design and installation is subject to local planning or building regulation requirements, but also in accordance with one of the principal standards below:

  • BSI documents used in the Commonwealth and the Middle and Far East.
  • NFPA Standard commonly used in the US and throughout the world.

There are many commonalities as well as differences between the two sets of standards.

The need for a fire alarm system in the first instance is determined by reference to local regulations and guidance, consultation with relevant approving authorities, client and insurer. The fire risk assessment may also indicate a need for a fire alarm system.

A building which is subject to a fire engineered design strategy may have different requirements and could require more comprehensive protection than basic requirements might indicate. It is also possible that the system may need a lower level of protection than indicated in the standards, due to a lower risk presented by the overall strategy.

Local requirements in the country in question may mean that a very simple solution is possible. In England and Wales, for example, although Building Regulations require that all new buildings must have a strategy in place for notifying occupants of a fire, in a small commercial premises (a shop) the requirement can be satisfied by someone shouting ‘Fire!’

In larger premises, this manual warning would not be sufficient and therefore an electrically operated fire alarm system will be necessary.

In residential buildings it is necessary to provide a system of automatic fire detection; in non-residential buildings, a fire alarm system comprised of manual call points may be considered sufficient protection.

The larger or more complex the new building is, the more likely it will be that a sophisticated analogue addressable fire alarm system is required.

As these examples show, in England and Wales, it is not necessarily the case that non-residential buildings need an automatic fire detection system using smoke detectors, although this standard is commonly seen.

In part 130 of LWF’s series on fire engineering, we will look at how the need for a fire alarm is identified and what level of coverage may be required. 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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