TABLE OF CONTENTS - The Professional Green Building Council

Theme B: Creating a livable, healthy and environmentally viable citiesWater consumption kl/m²32.521.510.501 star3 stars5 stars0 200 400 600 800 1000 1200 1400Cooling Degree Days base 15 WetbulbFigure 1: Rating bands superimposed on water consumption data as a function of climate.2.5.Area or Occupant Normalisation?A key issue in the derivation of any benchmark is the choice of normalisation.CIRIA provides benchmarks on the basis of both water use per occupant and perunit area, and these two normalisation factors are certainly the logical choices.In Australia, and indeed in other warm climates, there is a relatively strong reasonto choose area as the normalisation factor. This is because of the impact of coolingtower water use which is driven by floor area rather than occupancy. As discussedin the balance of this paper, the water consumption associated with cooling towersis a significant end-use, and this is increasingly the case in warmer climates.Furthermore, the correlation between floor area and occupant number is verystrong, making differentiation of these two factors difficult. Where analyses of theimpact of occupant density as a secondary variable have been undertaken on theavailable data, no statistically significant relationship has been able to be derived.This indicates that statistically, at least, floor area is an adequate descriptor ofwater performance.171