Pearl Building Rating System - Estidama

ROE = Volume of onsite/private offsite recycled water supplied to exterior uses
� EWA must not be ‘double counted’ towards other uses such as heat rejection and/or
water features. The design team must decide upon the most appropriate use of the
Exterior Water Allowance in order to balance their building wastewater volume with
their exterior water demand. The overall water balance must be documented in
the Building Water Calculator.
Example Calculation: Plant Selection
A multi-residential building has a building footprint of 6,000 m 2 and is located within a
16,000m 2 plot. It has a 500m 2 sky garden located on the roof which contains 100m 2 of
softscape requiring 6 l/m 2 /day and a 10m 2 water feature. At the base of the building
there is softscape requiring 8l/m 2 /day which covers an area of 3,000m 2 . Adjacent to
the ground level softscape is a 150m 2 water feature.
Plot Area, AP 16,000 m 2
Building Footprint, AB 6,000 m 2
Softscape Area (grade level), AS 3,000 m 2
Softscape Irrigation Demand (grade level), IS 8 l/m 2 /day
Water Feature Area (grade level), AW 150 m 2
Roof Amenity Area, ARA 500 m 2
Softscape Area (roof level), ARS 100 m 2
Softscape Irrigation Demand (roof level), IRS 6 l/m 2 /day
Water Feature Area (roof level), ARW 10 m 2
Total annual average irrigation demand of all
external softscape areas, IS
24,600 Liters / day
References � Pearl Rating System Building Water Calculator
Pearl Building Rating System: Design & Construction, Version 1.0, April 2010 128 of 223