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Pump set Power Supply for a Domestic Sprinkler System

Electron666

I am trying to finalise the power supply requirements for a pump set serving a shared water tank for both potable water use and also for domestic sprinkler system use to BS 9251.



Only apartments require a domestic sprinkler system – no landlord / communal areas.


The fire engineer and building control have both confirmed a secondary power supply is not required to the pump set.



Ideally we would like to feed the pump set from the load side of the main panel board via a MCCB.



However Section 5.9.1 of BS 9251 states the supply to the pump should come from ‘a separately fused connection taken after the meter and from the supply side of the fuse box ’ (I take this to mean the supply side of the customer switch in the plantroom).


Is there any guidance or publications that illustrate the required configuration in schematic form for this please? Is the fuse mentioned here a BS 88 fuse? If so, a concern might be difficulty in achieving 0.4s disconnection time.



Thanks in advance of any help


  • 0
    The supply should be from the live side of the consumers main switch, IE directly from the meter. This is so it remains live if the main switch is turned off, or if there is a catastrophic failure of the LV panel. 


    The relevant British Standards are 9251 (as you have already mentioned), BS8915 Power Supplies for Life Safety Systems and BS9991. These are also refenced in building regs part B. I can't recall any of them having a schematic though.


    regards,
  • 0
    Potable water from a tank? Doesn't potable water normally come directly from the cold mains to the kitchen tap? Tank water can be contaminated by insects, birds or vermin etc.


    What happens if the tank is empty after many people use water from it? Will there be enough for the fire extinguishing purpose should the need arise?


    Z.
  • 0
    Yes, in a large block of flats the incoming main won't be able to meet the peak demand so there will be a storage tank. It's capacity has to be calculated to support both the domestic water demand, and the sprinklers, for their required operational time, allowing for continuing refilling at the maximum the rate the incoming supply can support .


    regards 

  • 0

    Potable water from a tank? Doesn't potable water normally come directly from the cold mains to the kitchen tap? Tank water can be contaminated by insects, birds or vermin etc.





    It's a while since I looked at the water regs (bye laws as they were then) - but it certainly used to be possible to take potable water from a storage cistern (technically not a tank) - it used to be the case you needed a lid (to keep large items of detritus out), mesh filters on all the remaining holes (to exclude insects etc), dip tube on the overflow and thermal insulation to help keep the stored water cool. Kits of parts used to be sold as "Byelaw 30 kits" after the number of the regulation at the time.


      - Andy.

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