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| images by T.R. Hamzah & Yeang |
all information from http://www.trhamzahyeang.com/project/skyscrapers/edit-tower01.html
Description
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):
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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.
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| images by T.R. Hamzah & Yeang |
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.
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| images by T.R. Hamzah & Yeang |
Views to the Surrounding
A “views analysis” was carried out to enable upper-floor design to have views of surroundings.
“Loose-Fit”
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-jointing” 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.
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| Image by Isni Parra |
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%
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| Image by Isni Parra |
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 mode” 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.
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| Image by Isni Parra |
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:
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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.
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| Image by Isni Parra |
Facts
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
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)
