|
|
|
|
|
Project Name: EDITT
Tower
Client: URA (Urban Redevelopment Authority)
Singapore (Sponsor)
EDITT (Ecological Design in The Tropics) (Sponsor)
NUS (National University of Singapore) (Sponsor)
Date Start: 1998 (Competition: design)
Completion Date: Pending
Areas:
Total gross area: 6,033 sq.m.
Total nett area: 3,567.16 sq.m.
Total area of plantation: 3,841.34 sq.m.
|
Location:
Junction of Waterloo Road and Victoria Street,
Singapore
Nos. of Storeys:
26 Storeys
Site Area:
838 sq.m.
Plot Ratio:
7.1 |
|
|
Design Features
Our design sets out
to demonstrate an ecological approach to tower design.
Besides meeting the Client’s program requirements
for an exposition tower (i.e. for retail, exhibition spaces,
auditorium uses, etc.), the design has the following ecological
responses:
• |
Response to the Site’s
Ecology
Ecological design starts with looking at the site’s
ecosystem and its properties. Any design that do
not take these aspects of the site into consideration
is essentially not an ecological approach.
A useful start is to look at the site in relation
to an “hierachy of ecosystems†(see
below):
Ecosystem
Hierarchy |
Site Data
Requirements
|
Design
Strategy |
|
|
Ecologically-Mature |
Complete Ecosystem
Analysis and Mapping |
Preserve
Conserve
Develop only on no-impact
areas |
Ecologically-Immature |
Complete Ecosystem
Analysis and Mapping
|
Preserve
Conserve
Develop only on least-
impact areas |
Ecologically-Simplified |
Complete Ecosystem
Analysis and Mapping
|
Preserve
Conserve
Increase biodiversity
Develop only on low-
impact areas |
Mixed-Artificial |
Partial Ecosystem
Analysis and Mapping
|
Increase biodiversity
Develop on low-impact
areas |
Monoculture |
Partial Ecosystem
Analysis and Mapping
|
Increase biodiversity
Develop in areas of non-
productive potential
Rehabilitate ecosystem
|
Zeroculture |
Mapping of remaining
ecosystem components
(e.g. hydrology, remaining
trees, etc.)
|
Increase biodiversity and
organic mass
Rehabilitate ecosystem
|
|
|
From this hierachy, it is evident that this site
is an urban “zero culture†site and
is essentially a devastated ecosystem with little
of its original top soil, flora and fauna remaining.
The design approach is to re-habilitate this with
organic mass to enable ecological succession to
take place and to balance the existent inorganicness
of this urban site.
The unique design feature of this scheme is in the
well-planted facades and vegetated-terraces which
have green areas that approximate the gross useable-areas
(i.e. GFA @ 6,033 sq.m.) of the rest of the building.
The vegetation areas are designed to be continous
and to ramp upwards from the ground plane to the
uppermost floor in a linked landscaped ramp. The
design’s planted-areas constitute 3,841 sq.m.
which is @ ratio 1 : 0.5 of gross useable area to
gross vegetated area.
Design began with the mapping in detail of the indigenous
planting within a 1 mile radius vicinity of the
site to identify species to be incorporated in the
design that will not compete with the indigenous
species of the locality. |
|
|
• |
Place Making
A crucial urban design issue in skyscraper design
is poor spatial continuity between street-level
activities with those spaces at the upper-floors
of the city’s high-rise towers. This is due
to the physical compartmentation of floors (inherent
in the skyscraper typology).
Urban design involves ‘place making’.
In creating ‘vertical places’, our design
brings ‘street-life’ to the building’s
upper-parts through wide landscaped-ramps upwards
from street-level. Ramps are lined with street-activities:
(stalls, shops, cafes, performance spaces, viewing-decks
etc.), up to first 6 floors.
Ramps create a continuous spatial flow from public
to less public, as a “vertical extension of
the street†thereby eliminating the problematic
stratification of floors inherent in all tall buildings
typology. High-level bridge-linkages are added to
connect to neighbouring buildings for greater urban-connectivity. |
|
|
• |
Views to the Surrounding
A “views analysis†was carried out to
enable upper-floor design to have views of surroundings. |
|
|
• |
“Loose-Fitâ€
Generally, buildings have life-spans of 100-150
years and change usages over-time. The design here
is ‘loose-fit’ to facilitate future
reuse. Features include:
• |
‘Skycourts’
(i.e. convertable for future office use) |
• |
Removable partitions |
• |
Removable floors |
• |
“Mechanical-jointingâ€
of materials (as against to chemical bonding)
to facilitate future recovery. |
• |
Flexible design (e.g. initially
a multi-use expo building, its future use
may be offices [nett lettable area of 9,288
sq.m. @ 75% efficiency] or apartments). |
|
|
A set of plans to show conversion to office use
has also been prepared @ 75% net to gross floor
efficiency. |
|
|
• |
Vertical Landscaping
Vegetation from street-level spirals upwards as
a continuous ecosystem facilitating species migration,
engendering a more diverse ecosystem and greater
ecosystem stability and to facilitate ambient cooling
of the facades.
As mentioned earlier, species are selected not to
compete with others within surroundings. “Vegetation
percentages†represent of area’s landscape
character. Factors influencing planting selection
are:
• |
Planting depths |
• |
Light Quality |
• |
Maintenance level |
• |
Access |
• |
Orientation |
• |
Wind-walls / solar-panels
/ special glazing |
|
|
Vegetation placements within the tower at different
heights respond to the microclimates of each individual
sub-zone at the tower. |
|
|
• |
Water-Recycling
Water self-sufficiency (by rainwater-collection
and grey-water reuse) in the tower is at 55.1%:
• |
Total gross area |
= 6,032 sq.m. |
• |
Water requirements |
= 20 gallons/day/10 sq.m.
gross area + 10% wastage |
• |
Total requirements |
= (6,032 ÷ 10 x
110%) x 20 gallons
= 13,270 per gallon/day
= 60.3 m3 per day x 365 days
= 22,019 m3 annum |
• |
Total rain-fall catchment
area |
= 518 sq.m. |
• |
Singapore average rainfall
/ annum |
= 23.439m |
• |
Total rain-water collection |
= 12,141 m3 per annum |
• |
Water self sufficiency
|
= 12,141 ÷ 22,019
x 100 = 55.1% |
|
|
|
• |
Water-Purification
Rainwater-collection system comprises of ‘roof-catchment-pan’
and layers of ‘scallops’ located at
the building’s facade to catch rain-water
running off its sides. Water flows through gravity-fed
water-purification system, using soil-bed filters.
The filtered-water accumulates in a basement storage-tank,
and is pumped to the upper-level storage-tank for
reuse (e.g. for plant-irrigation and toilet-flushing).
Mains water is only here for potable needs.
|
• |
Sewage Recycling
The design optimises recovery and recycling of sewage
waste:
• |
Estimated sludge |
= 230/P.E. / day @ 3.
P.E. per 100 m2 GFA |
• |
Building GFA |
= 6,032 sq.m. |
• |
Sewage sludge collected/day |
= 230 litres x 6,032 ÷
100 x 3
= 41,620.8 litres or 41.62 m3/day
= 15,190 m3/ annum |
|
|
|
Sewage is treated to create compost (fertilizer
for use elsewhere) or bio-gas fuel. |
|
|
• |
Solar Energy Use
Photovoltaics are used for greater energy self-sufficiency.
• |
Average photovoltaic-cell
energy output |
= c. 0.17 kWh sq.m. |
• |
Total sunlight hours per
day |
= 12 hours |
• |
Daily energy output |
= 0.17 x 12 = 2.04 kWh
sq.m. |
• |
Area of photovoltaic |
= 855.25 sq.m. |
• |
Total daily energy output
|
= 1,744 kWh |
• |
Estimated energy consumption
@ 0.097 kWh /sq.m. enclosed |
& 0.038 kWh/sq.m.
unenclosed
= (0.097 x 3,567 sq.m.) + (0.038 x 2,465 sq.m.)
= 439.7 kWh |
• |
Estimated daily energy
consumption |
= 10 hrs x 439.7
= 4,397 kWh |
• |
% self sufficiency is
1,744 ÷ 4,397 |
= 39.7% |
|
|
|
|
• |
Building Materials Recycling
and Reuse
Design has an in-built waste-management system.
Recycleable materials are separated at source by
hoppers at every floor. These drop-down to the basement
waste-separators, then taken elsewhere by recycling
garbage collection for recycling.
Expected recycleable waste collected /annum:
• |
paper / cardboard |
= 41.5 metric-tonnes |
• |
glass / ceramic |
= 7.0 metric-tonnes |
• |
metal |
= 10.4 metric-tonnes |
|
|
|
The building is designed to have mechanically-joined
connections of materials and its structural connections
to facilitate future reuse and recycling at the
end of building’s useful-life. |
• |
Natural Ventilation &
“Mixed-Mode†Servicing
The options for the M&E servicing modes for
any ecological building are:
• |
passive mode |
• |
background (mixed) mode |
• |
full (specialised) mode |
|
|
The design here optimises on the locality’s
bioclimatic responses using ‘mixed modeâ€
M&E servicing. Mechanical air-conditioning and
artificial-lighting systems are reduced. Ceiling-fans
with de-misters are used for low-energy comfort-cooling.
Wind is used to create internal conditions of comfort
by “wind-walls†that a placed parallel
to the prevailing wind to direct wind to internal
spaces and skycourts for comfort cooling. |
• |
Embodied Energy and CO2
Embodied-energy studies of the building are useful
to indicate the building’s environmental impacts.
Subsequently, estimates of CO2 emissions arising
from building materials production may be made.
Design’s embodied-energy (prepared by our
expert) is:
|
Structural
System |
• Excavation
• Steel and concrete
• Formwork
|
764.0
43,850.2
3,113.10 |
Floor |
• Steel • Timber
& other material •
Staircases & railings
• Floor finishes
|
13,013.10
22,648.00
1,752.50
7,793.00 |
External wall |
• Curtain wall and bricks
• Aluminium cladding
• Solar panels
|
5,550.30
2,864.50
12,435.70 |
External wall and partitions |
• Bricks • Other
materials
|
5,482.20
6,078.30 |
Roof and ceilings |
• Concrete & membrane
• Water catchment and
drainage • Ceiling
|
5,439.00
8,439.80
1,390.70 |
Fittings |
• Doors • Sanitary
fittings
|
1,736.60
490.20
|
|
Total: |
142,841.20 |
|
|
|
|
|
Energy sources affect CO2 emissions associated with
embodied-energy. If the majority of energy sources
is petroleum-related (with some gas and electricity),
80 kg CO2 per GJ of energy averages. The building
here is associated with emissions of c. 11.5 thousand
tonnes CO2.
Embodied-energy ratio to gross floor area (GJ/m2
GFA) is generally between 6 and 8, but may be more
depending on methodology used. The design’s
ratio is at the high end (@ 14.2 GJ/m2 GFA) but
differs from others since using solar-panels having
high embodied-energy will significantly offset operational-energy
saved over building-life. High embodied-energy materials
used (e.g. aluminium and steel) are however easily
recycleable and therefore halving their embodied-energy
when reused. Replacing concrete floors with composite
timber-floors casettes will reduce embodied-energy
by c. 10,000 GJ. |
|
|
Project Team : |
|
Principal-in-charge:
Dr. Ken Yeang
Design Architects :
Ridzwa Fathan (PIC)
Claudia Ritsch
Azman Che Mat
Design Team :
Azuddin Sulaiman
See Ee Ling |
Project Architect:
Andy Chong
Drafting :
Sze Tho Kok Cheng
C&S and M&E Engineers :
Battle McCarthy (London)
Embodied Energy Expert :
Bill Lawson (University of Sydney)
Swan & Maclaren Architects :
James Leong (Architect-of-Record) | | | | |