The LWF Blog

Fire Engineering Design and Risk Assessment – Firefighting & External Water Supplies – Part 24

January 23, 2019 12:26 pm

In LWF’s fire engineering blog series for Architects and other professionals involved in building design, we have been looking at firefighting and, most recently, the provisions that should be made for the Fire Service to attend and put out a fire. In part 23, we looked at the requirements and recommendations relating to the provision of fire hydrants and we continue from that point in part 24.


The original standards for the installation of water hydrants in the UK had recommendations for spacing the hydrants between 90 metres and 180 metres, however, with risk assessment becoming ever more essential, it is increasingly relied upon to indicate the necessary spacing between hydrants in those areas which require them to be provided.


BS 750:2012 Specification for underground fire hydrants and surface box frames and covers provides the requirements to which all hydrants in use in the UK must comply and states that each hydrant must be capable of delivering no less than 2000 litres per minute at a constant pressure of 1.7 bar (measured at the hydrant). This measurement will, of course, rely on the minimum flow rate from the water provider meeting that level and as there is no legislatory requirement for water suppliers to provide minimum flow rates for firefighting, it may not be achievable in some areas.


When considering how to best locate a hydrant to provide water for firefighting purposes, it makes sense that the guidance documents mentioned in the last few blogs would be referred to. However, the varying advice in different documents can sometimes be confusing.


Practical requirements should therefore be paramount. It is important that the water supplies for firefighting should be carried on the first pump appliance and that it contains enough water to deploy a single stopping jet. The locations of the hydrants should be such that they can provide supplementary water supplies before the water in the pump appliance runs out.


In part 25, we will continue to look at the practical requirements to be considered when deciding where to place water hydrants. 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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