The LWF Blog
Fire Safety Engineering for Design – Sprinkler Protection – Part 222
February 17, 2025 11:46 amLWF’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 221, LWF talked about the extinguishing mechanism of sprinkler systems, which could be summarised as ‘wetting, cooling and inerting’. In part 222, we consider the rules and standards for sprinkler installations.
There are design codes for sprinkler systems available internationally. The European Standard BS EN 12845: 2020 is widely used, superseding BS 5306-2 in the UK. The UK’s specific requirements are laid out in technical bulletins which are incorporated into BS EN 12845 and form the Loss Prevention Council’s ‘Rules for Automatic Sprinkler Installations‘.
There are a number of other internationally accepted design codes available:
— NFPA 13: Standard for the installation of sprinkler systems (USA) (NFPA, 2016a)
— FM Data Sheet 2-0: Installation guidelines for automatic sprinklers (USA) (FM Global, 2014) (PDF)
— CEA 4001: Sprinkler systems planning and installation (Europe) (CEA, 2006) (PDF)
In the main, we will concentrate on the standards as relevant in the UK, although relevant comparisons with NFPA standards may be made.
Overall, sprinkler system design is intended to be for the entire building to be protected, although each of the standards above has areas of exception possible. Sprinklers are designed to suppress fire at a very early stage of fire development and would not be as successful at suppressing a larger, already-established fire.
Where it is deemed appropriate to leave an area of a building without sprinkler coverage, then other provisions to stop the passage of fire from that area should be made, for example, fire-resisting construction, automatic fire detection and, where required, other automatic firefighting systems.
Design codes, generally-speaking, advise that sprinkler protection should apply to the entire building, any building communicating with it and any neighbouring building that may present an exposure hazard to the building in question.
In cases where the communicating building or neighbouring building risk is not to be protected by sprinklers, then the protected building should be separated from the risk posed. This may be satisfied by the nature of the structure between the risk areas, but can be supplemented by an external drencher system, for instance.
A fire-engineered approach would involve an assessment of the fire load, level of fire-resisting construction and the associated risks of fire spread potential. Once completed, it is possible to protect only risk areas with sprinkler coverage. Compartmentation between sprinkler and non-sprinkler areas is recommended.
In part 223 of LWF’s series on fire engineering we will continue to discuss exceptions to sprinkler protection throughout a building. 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.