Abstract :
The author discusses design work carried out for data processing centres of up to 5000 sq m with a maximum data processing density of 850 W/sq m. It has to be said that this density was never actually reached, the standard density of about 500 W/sq m being more realistic. This highlights the underlying fact that we are working in a rapidly changing industry. Some of the solutions designed into the buildings seemed right at the time, but have proved not to be ideal. The author discusses power usage, power supply harmonic waveforms, computer centre cooling, and the resilience of the power supply including condition of supply, loss of supply and maintenance