5.3.3 Irrigation
A shopping mall usually includes some green planting areas. Therefore, an irrigation system is also one of the major
water consumption items. Where applicable, use drought resistant plants or local species to suit the local rainfall
pattern to save on water consumption. Advanced water efficient irrigation systems (such as drip line irrigation system,
solar wireless-intelligent weather control irrigation system, or recycled water system) can also be used for water saving.
Readers may also refer to
.
5.3.4 Metering and accounting
Sub-meters should be installed on all major water systems, such as cooling towers, irrigation, toilets, etc. The readings
taken can give a better picture of water consumption in buildings. By monitoring water usage, water saving opportunities
can be identified.
5.3.5 Other design considerations
Apart from savings on water consumption, the energy consumed by the plumbing and drainage systems should be
reduced wherever feasible. Direct feed systems and gravity water supply systems should be used whenever possible.
If practical, the drainage system should be designed with a gravity fall instead of a sump and pump system. For up-feed
pumping, variable speed pumps should be adopted.
Other design considerations include:
• Twin water tanks installation:
This provides an uninterrupted supply of fresh and flush water to
tenants, reducing water wastage during maintenance or cleaning,
and improving the durability of the building’s roof structure.
Figure 109 Typical twin water tanks in
buildings
(Source: Hong Kong Housing Authority)
• Reuse of harvested rainwater, air-conditioning system condensate, municipally reclaimed water or non-potable water
from any other appropriate source for cooling tower make-up water.
• Recycling cooling tower bleed-off water for flushing.
5
Energy efficient building systems for shopping malls and shop spaces
5.3
Plumbing and drainage
Hong Kong Green Building Council 133
