The LWF Blog
Fire Safety Engineering for Design – Sprinkler Systems – Part 236
May 27, 2025 10:13 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 235, LWF gave an overview of the thermal sensitivity of sprinkler heads. In part 236, we look at the types of sprinkler system.
When considering what type of sprinkler system would be most appropriate for use in a given scenario, an appreciation of how a sprinkler system works and the ways in which sprinkler operations vary is useful. The basic tenets of sprinklers – method of water supply, how the water supply is controlled and how the alarm is raised in case of a fire – are all considerations dependent upon the intended location and environment.
A common element for all sprinkler system types is a way to isolate the sprinkler system from the water supply and this is accomplished through valves. One or more valves may be placed in the supply line to allow the system to be shut down by the Fire Service following a fire or if the system needs to be shut down for maintenance, repair or alteration.
A sprinkler installation should be engineered where possible so that shut downs are feasible in an affected area, while remaining operational elsewhere. This can be achieved by using adopting zone or sectional valves.
For systems in dry mode (i.e. the pipes are not charged with water ready for operation, commonly due to the potential for water freezing in the pipes) the delivery speed of the water in the event of a fire should be consideration. A max pipe volume of 2.5 m3 may be appropriate, or delivery of water to the most remote single sprinkler within 60 seconds.
Where a sprinkler installation is a part of a fire-engineered solution, the delivery delay of water from a sprinkler once operated must be taken into account in the design. The limitation of fire size cannot begin until the water is delivered from the appropriate sprinkler head and the effectiveness of the sprinkler’s operation could be compromised if the delay is excessive.
In part 237 of LWF’s series on fire engineering we will give an overview of wet installations and alternate wet and dry installations. 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.