The LWF Blog

Fire Engineering Design and Risk Assessment – Sprinkler Installation Design – Part 40

April 5, 2018 3:46 pm

In LWF’s Fire Engineering blog series for Architects and others involved in building design, we have been looking at fire suppression. In part 39, the standards relating to the installation and maintenance of sprinkler systems was discussed and in part 40, we move on to talk about Life Safety Systems.


While sprinkler systems are considered in the main to be a property protection provision, the way they control fire means that they are also useful as a life safety system. The subduing of the fire means that there is more time for building occupants to evacuate and for firefighters to arrive and do their work.

Some sprinkler systems are installed purely to improve life safety risk.


The installation of a sprinkler system allows concessions to be made in terms of other types of fire safety measure, or where a risk would be too great without the use of a sprinkler system.


One example of a sprinkler system being used for life safety purposes is within shopping centres. Sprinkler systems are installed into each individual shop within a complex to help stop the spread of fire between areas. Such life safety installations allow individuals to safely evacuate and make the area less dangerous for firefighters to enter and make safe.


Of course, where a sprinkler system is used for life safety purposes, it becomes even more essential that it is maintained correctly so that it can be relied upon in a fire situation.


Where a sprinkler system is to be used for life safety purposes, it must fulfil certain criteria, set out by UK design codes. The system must be ‘wet’ (i.e. permanently charged with water) and should be arranged into sprinkler zones which include no more than 200 sprinklers covering one ownership and floor level.


The water flow into each installation must be monitored and the device must be connected to a fire alarm system. Water flow alarm switches may be necessary to monitor water flow in each separate zone.


The control valves for the sprinkler system should be arranged with either a valved bypass or with a parallel duplicate valve set so that maintenance can be undertaken without interruption of water supply to the system.


All stop valves must be electrically monitored and tamper-proof on the path between the water source and the sprinkler head. Flushing valves are also necessary in each zone.


When it comes to the type of sprinkler system necessary for life safety purposes, the choices are limited. It would not be appropriate to install ceiling, flush, recessed or concealed sprinklers.


In systems complying with BS 9999, a duplicate water supply is necessary and all systems must have a reliable water source.


In addition, the block plan should provide additional information showing zone valve locations and all procedures required in order to undertake maintenance must be followed precisely.


In part 41, LWF will look at enhanced sprinkler systems for property protection. 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 for over 25 years to produce innovative and exciting building projects. If you would like further information on how LWF and fire strategies could assist you, please contact Peter Gyere on 020 8668 8663.


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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