Diversity

Is the whole building supplied as single phase ?


As a sensible starting point, what's the gross internal area (GIA) - from there apply something like 35W/m2 to give you a total kW demand (everything credible in an office building)


If you then take a floor by floor approach and apply a diversity of something like 0.8 to the total figure above and pro rata that back to the total GIA you should then get a sensible value per floor


From there you should be able to apply at least a factor of 0.8 to the sum total of each floor

In summary, apply 35w/m2 to the GIA and diversify that by 0.8 per floor and a further 0.8 to collect each floor at the intake (or as a single step, GIA(m2) x 35 x 0.64 = facility W/m2


You can deduce amps from kW when you have the numbers (remembering if it is 3 phase, you would ideally like some balance across the phases, so assume 33% of demand is on each phase)


The above is conservative, and includes pretty well everything required like lifts, electrical input into ventilation and other mechanical plant, but doesn't include any electrically driven heating or cooling (VRF, Chillers and the like)


If you can find a copy, look at the British Council for Offices guidance which might suggest that you actually only need about 15m2 for the office space (power and lighting) - but that's diversified for a reasonably big building where you expect some people to be off site, on leave, in meetings etc)


Regards


OMS

Is the whole building supplied as single phase ?


As a sensible starting point, what's the gross internal area (GIA) - from there apply something like 35W/m2 to give you a total kW demand (everything credible in an office building)


If you then take a floor by floor approach and apply a diversity of something like 0.8 to the total figure above and pro rata that back to the total GIA you should then get a sensible value per floor


From there you should be able to apply at least a factor of 0.8 to the sum total of each floor

In summary, apply 35w/m2 to the GIA and diversify that by 0.8 per floor and a further 0.8 to collect each floor at the intake (or as a single step, GIA(m2) x 35 x 0.64 = facility W/m2


You can deduce amps from kW when you have the numbers (remembering if it is 3 phase, you would ideally like some balance across the phases, so assume 33% of demand is on each phase)


The above is conservative, and includes pretty well everything required like lifts, electrical input into ventilation and other mechanical plant, but doesn't include any electrically driven heating or cooling (VRF, Chillers and the like)


If you can find a copy, look at the British Council for Offices guidance which might suggest that you actually only need about 15m2 for the office space (power and lighting) - but that's diversified for a reasonably big building where you expect some people to be off site, on leave, in meetings etc)


Regards


OMS