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BEAM P
LUS FOR
N
EW
B
UILDINGS
W
ATER
U
SE
(W
U
)
V
ERSION
1.2
W
U
P2 M
INIMUM
W
ATER
S
AVING
P
ERFORMANCE
Copyright © 2012 BEAM Society Limited. All rights reserved.
Page 126
Water consumption of flow devices (faucets, showers, etc):
Device/
equipment
Rated Flow
rate
Duration of
each
operation
Daily
Number of
Uses
Daily Water Use
Water consumption of utensil washing operation by hand:
Device/
equipment
Water Use
per
operation
or cycle
Daily
number of
operations
Daily Water Use
The calculations can be summarised as follows:
Project case
Baseline case
Estimated total daily
consumption (litres)
Estimated total annual
consumption (litres)
Estimated annual savings (litres) and percentage:
Where it can be demonstrated that the provision of equipment meets the
intent, the requirement shall be fulfilled. Confirmation of the award of
credits shall take into account the appropriateness of the data used and
the estimated percentage of potable water saved.
B
ACKGROUND
Hong Kong differs from most other places in the world because most
buildings have a saltwater flushing supply rather than using potable
water. Therefore the scope for potable water reductions may be more
limited here than elsewhere. Locally, neither the quantification of water
use nor the potential for savings has been addressed in the research
literature. Nevertheless, evidence from other countries suggests that
reductions in water use may be achieved through the use of water
efficient devices and automatic controls.
For the majority of projects, a limited amount of hand washing and
perhaps some manual dish washing will take place in the pantry. It is not
the intention to include water used for washing food or produce (required
for hygiene), nor water used for coffee making machines, etc.
There is an increasing availability of devices and plumbing fixtures which
have demonstrated an ability to save water over the lifetime of the
system if installed and maintained properly. Flow rates can be controlled
to reduce excessive discharge at taps, faucets and showers without
detriment to the quality of water delivery. Substantial evidence shows
that the use of water-efficient plumbing fixtures conserves water [1]. A
number of studies in the U.S. have measured the impact of installing
water-efficient plumbing fixtures through sophisticated sensors, before
and after comparisons of water bills, or other means. Although the
results varied, the studies generally concluded that low-flow fixtures are
effective in saving water.
High efficiency devices include low flow rate faucets or faucets with
aerated flows. However it must demonstrate that the actual quantity of
water is reduced per standard operation (e.g. in the case of hand
1
United States General Accounting Office. Report to Congressional Requesters. Water Infrastructure. Water-Efficient
Plumbing Fixtures Reduce Water Consumption and Wastewater Flows. GA RCED-00-23. August 2000.