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Sizing a Generator for a building

Apostolos

Good afternoon

I would like to ask if anyone is aware of any BS standard that provides any guidelines on how to size a generator set

We currently have a big hotel that has life safety systems (fire fighting lift, smoke ventilation, sprinkler system...etc)

Is there anything in the British Standards about this or we go by the common sense?

At this stage I have to say that in the past I have heard the following rule:

'It has to be able to start the biggest motor (highest starting current) while everything else is operating'

However in this very project its the first time the sprinkler subcontractor asked us to size the generator based on 1 sprinkler pump at locked rotor and the standby pump starting. So after this if I add all the rest (smoke vent panel, fire fighting lifts, car park smoke vent etc) this leads to a huge total current so I am starting this discussion in case someone know of any official guidelines or any other help is appreciated

Thanks

Parents

  • As far as the sprinkler pumps go, BS EN 12845 applies, and LPC TB210 may also apply. For domestic and residential BS 9251 applies. The requirement to size the generator based on 1 sprinkler pump stalled and the other starting comes from LPC TB210. There are a whole host of other requirements, too much to go into here but the basics are, for a BS EN 12845 / TB210 compliant installation, assuming 2 or more electric pumps:

    • Electrical supply taken from the input side of the main switch if permitted. Confirmation of permission should be sought from the DNO / designer as appropriate.
    • Supply to be available at all times.
    • Dual sources of supply.
    • Separate dual supplies to each pump.
    • Fire-resistant diverse cable routes.
    • HRC fuses.
    • Automatic transfer switch (ATS) per pump.
    • Pumps enclosed in 2 hour fire-resistant enclosure.
    • Cable installation to BS 8519 (eg: enclosure of cables in areas of special fire risk, derating of cables in enclosures, cable selection meeting Category 3, separation of wiring from circuits provided for any other purpose and so on.)
    • Supplies to be able to support LRA of one pump and start current of remaining pumps.
Reply

  • As far as the sprinkler pumps go, BS EN 12845 applies, and LPC TB210 may also apply. For domestic and residential BS 9251 applies. The requirement to size the generator based on 1 sprinkler pump stalled and the other starting comes from LPC TB210. There are a whole host of other requirements, too much to go into here but the basics are, for a BS EN 12845 / TB210 compliant installation, assuming 2 or more electric pumps:

    • Electrical supply taken from the input side of the main switch if permitted. Confirmation of permission should be sought from the DNO / designer as appropriate.
    • Supply to be available at all times.
    • Dual sources of supply.
    • Separate dual supplies to each pump.
    • Fire-resistant diverse cable routes.
    • HRC fuses.
    • Automatic transfer switch (ATS) per pump.
    • Pumps enclosed in 2 hour fire-resistant enclosure.
    • Cable installation to BS 8519 (eg: enclosure of cables in areas of special fire risk, derating of cables in enclosures, cable selection meeting Category 3, separation of wiring from circuits provided for any other purpose and so on.)
    • Supplies to be able to support LRA of one pump and start current of remaining pumps.
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