The LWF Blog

Fire Engineering Design and Risk Assessment – Planning Sprinkler Installations – Part 30

January 23, 2018 10:55 am

In LWF’s Fire Engineering and Risk Assessment blog series for Architects and others in the building design industry, we have been looking at the ways of planning for a sprinkler installation and the types of conditions that should be taken into account. Part 29 looked at the potential sources of water to feed the sprinklers and in part 30, we will discuss the first stages of a sprinkler going ‘live’ and how the installation should be designed.


Emergency planning for a building should include the potential for water runoff caused by activation of the sprinkler system. In addition, if the Fire Service attend and use their hoses, this will cause additional water to be present that will need clearing. There is a potential for greater disruption where materials that are dissolved by water, or where water runoff could be contaminated by chemicals. Similarly, where the Fire Service use alternative fire-fighting media, such as synthetic foams, the runoff must be considered and contained where possible. Fire water runoff can be very detrimental to the environment.


Although it may be that the sprinkler system installation is not designed to go live until the building is completed and ready for occupation, fires on construction sites are common and it can be a distinct advantage to have fire protection features online at the earliest opportunity. The planning process must consider whether early protection is required and if so, obtaining a suitable water supply is a high priority. It might be that this requires a temporary connection to the water mains or the use of a temporary power supply such as diesel or electric fire pumps.


Where it is not possible to get the sprinkler system online with water and power in the construction phase, it is advisable to install a fire service breeching inlet at ground level, which means the fire service can access the system in place to pump water in. Use of a breeching inlet by the Fire Service relies on the pipework for the sprinkler system being complete, or partially complete.


When considering the design of the sprinkler installation, the spacing and placement of the sprinkler heads are of the utmost importance. A simplified example is that a space within the building protected by ten evenly spaced sprinkler heads will have more protection from fire than the same space protected by only two heads at one end or the other. Equally, too many sprinkler heads would not only prove expensive in terms of the cost of the product and installation but might also cause water damage. It is important, therefore, that consideration is given to what is needed.


In Part 31, LWF will look at the principles of sprinkler installation design as a guide. 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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