The LWF Blog

Fire Safety for Healthcare Premises – Sprinklers – Part 46

November 1, 2018 12:35 pm

In LWF’s blog series for healthcare professionals, the aim is to give information on best practice of fire safety in hospitals and other healthcare premises. In part 45 of this series, the use of sprinklers as a life safety system was discussed and in part 46, LWF will examine the necessary water supplies required for sprinkler use.


Historically, there were two pieces of information which inform the requirements for water supply to non-residential sprinkler systems. One was BS 5306-2, which was withdrawn and superseded by the other, BS EN 12845 Fixed firefighting systems. Automatic sprinkler systems. Design, installation and maintenance


The guidance provided in HTM 05-02 assumes that both are still in use, however, systems should be designed and installed to the standards contained in BS EN 12845 only.


Such adherent systems may consist of either:


 Two single water supplies complying with BS EN 12845, clause 9.6.1, where each is independent of the other




 Two stored water supplies, where the following arrangements apply:


 o Gravity or suction tanks should satisfy all the requirements of BS EN  12845, clause 9.6.2 b) other than capacity; and


 o Any pump arrangements should comply with clause 10.2; and

 o The capacity of each tank is equivalent to half the specified minimum  water volume of a single full capacity tank, as appropriate to each  hazard; or


 o One tank should be at least equivalent to half the specified water  volume of a single full capacity tank and the other should be not less  than the minimum volume of a reduced capacity tank (see BS EN  12845, clause 9.4.40), as is appropriate to each hazard.


It should also be noted that the requirements for inflow must be met. Therefore, whichever water storage arrangement is used, the total capacity of the water supply, including any inflow for a reduced capacity tank, should be at least equivalent to a single full capacity tank complying with BS EN 12845, Tables 9 and 10 or clause, as is appropriate to the hazard and pipework design.


Where pumps are used to draw water from two tanks, each pump should be able to draw water from either tank and so that any one pump or either tank could be isolated if necessary.


The water supplies for a sprinkler system should not generally be connected to other services or other fixed fire-fighting systems.


In part 47 of this series, LWF will continue looking at sprinkler systems and water supply to those systems. 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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