SUSTAINABILITY - National University of Singapore

119S U S TA I N A B I L I T YN O V 2 0 0 9

S U S TA I N A B I L I T Y6

120 S U S TA I N A B I L I T YN O V 2 0 0 9

The university will be designed to eliminate waste of resources through the capture and reuse of waste flows of energy, water, and materials. This system benefits from the diverse uses of the university campus – finding synergies between varying building types.

The sustainable master plan lays a path to an envisioned future for the campus where resources are used wisely, with minimized waste and reduced operating costs, while creating a healthy and inspiring environment that contributes to the environmental health of the site and its surrounding region.

In addition, a good environmental design will contribute to better security campus wide. CPTED (Crime Prevention Through Environmental Design) utilizes its surroundings inclusive of natural and constructed elements such as raised turf and lighting. This will create an interaction between human behavior and the built environment which lead to reduction in fear and incidence of crime towards improved quality of life.

The foundation for this design process is to carry out research into the ecology of the site, the climate, the culture, the community of people served by the campus, and a survey of existing facilities.

With that understanding, we consider questions about how to meet the future plans for development on the campus in a way that is in balance with nature and user patterns, and that is economically feasible over the long term of the campus. NUHS and NUS plans to expand its campus with facilities that are more energy-intensive in nature, such as wet laboratories and acute patient care, which present a challenge to the university as it seeks to reduce its energy consumption and operating expense overall. This plan seeks solutions which will reduce the energy consumption of current facilities and minimize energy consumption to the greatest degree feasible for new construction.

The integrated design process is comprised of a series of inquiries in a logical progression towards a design solution: Information Gathering, Prioritization, and Definition of Standards for campus development. For each primary area of environmental impact outlined below, those steps were taken, resulting in the following recommendations listed in the following pages:

As part of the environmental design, CFD study is recommended for exhaust, safety and natural ventilation.

6 . 1 S U S TA I N A B L E D E S I G N P R O C E S S A N D R E C O M M E N D AT I O N S


Future development and retrofits are to use the following standards to improve conservation of energy:

ETTV stands for Envelope Thermal Transfer Value of the building, as determined in accordance with the formula set out in BCA’s “Code on Envelope Thermal Performance for Buildings” and it is applicable to air-conditioned building spaces with aggregate areas > 500 m2. ETTV should be targeted in the range of at least 44 W/m2. The baseline standard based as specified in the Code on Envelope Thermal Performance for Buildings issued by BCA is 50W/m2. The salient parameters such as material properties for the façade or external wall system, shading provision and louvre glazing shall be selected accordingly to meet this requirement.

Air distribution system (Air Handling Units (AHUs) & Fan Coil Units (FCUs)) shall comply with Clause 7.11.5 in SS CP13. The design for the air distribution system

efficiency shall target an improvement of at least 10% above regulatory baseline efficiency requirements.

For air-conditioned distribution area, CO2 sensors or similar automatic control devices to be installed to regulate outdoor air flow rate to maintain the concentration of CO2 to the level of less than 1000ppm.

Mechanically ventilated carparks shall be adequately incorporated with carbon monoxide (CO) sensors to regulate the amount of mechanical ventilation (MV) where applicable for carparks. It is encouraged to consider fully naturally ventilated design or otherwise incorporating fume extract system or combination of different ventilation modes to reduce MV. Ventilation shall be adequately provided in all building for its intended occupancy.

(a) Where natural ventilation is applicable, it shall be provided by means of openable windows or other openings with an

Note: This requirement does not apply to building with an aggregate floor area not exceeding 500 m2, open sided sheds, covered walkways and linkways, store rooms and utility rooms or plants and equipment rooms.

Maximum Thermal Transmittance for Roof of Air-Conditional Building(Reference: Code for Environmental Sustainability of Buildings Version 1.0)

Maximum Thermal Transmittance for Roof of Non- Air-Conditional Buildingng(Reference: Code for Environmental Sustainability of Buildings Version 1.0)

aggregate area of not less than –(i) 5% of the floor area of the room or space required to be ventilated; and (ii) 15% of the floor area of the aboveground car parking area required to be ventilated.

(b)Where mechanical ventilation or air-conditioning systems are used, the ventilation rates of these systems shall comply with SS CP 13 – Code of Practice for Mechanical Ventilation and Air-Conditioning in Buildings.

To encourage the use of energy efficient design and control of ventilation systems in common areas i.e. toilets, staircases, corridors, lift lobbies, atriums etc, natural ventilation systems shall be used wherever applicable. If natural ventilation is not applicable, MV system shall be used.

In respect of roofs with skylight, the roof thermal transfer value (RTTV) as determined in accordance with the formula set out in the “Code on Envelope Thermal Performance for

Buildings” shall not exceed 50W/m2.

In respect of roofs without skylight, the average thermal transmittance (U-value) for the gross area of the roof shall not exceed the limit prescribed in the following Tables for the corresponding weight group:

6 . 2 . 1 E N E R G Y E F F I C I E N C Y6 . 2 S U S TA I N A B L E D E S I G N C O M P O N E N T S


Air Tightness and Leakage:

(a) All windows on the building envelope shall not exceed the air leakage rates specified in SS 212 –Specification for Aluminum Alloy Windows.

(b) Where the door opening is located along the perimeter of the building envelope or leading to an exterior open space, external corridor, passageway or pedestrian walkway, that unit shall – (i) be completely separated from the other parts of the building; and (ii) has its air-conditioning system separated from and independent of the central system.

To ensure good thermal comfort, it is required to design air-conditioning systems which would provide consistent indoor conditions for thermal comfort as stated below:

•Indoor temperature between 22.5 to 25.5 °C

•Relative Humidity < 70%

The occupied space shall be designed with ambient sound levels to the recommendation stated in CP 13 and shall include detailed analysis, calculations and/or measurements to ensure that the designed ambient sound levels are met.

Energy of lighting consumption shall be minimized with properly designed lighting level;

(a) Lighting control for artificial lighting shall be provided in accordance with SS 530.

(b) The design for the lighting system shall target the improvement of at least 20% above the baseline. (Baseline = Maximum lighting power budget stated in SS 530,Code of Practice for Energy Efficiency Standard for Building Services and Equipment)

(c) Building lighting is to be maintained at luminance level as stated in CP 38 – Code of Practice for Artificial Lighting in Buildings for various types of occupancy and in SS 531: Part 1 : 2006 – Code of Practice for Lighting of Work Places where appropriate.

Electrical sub-meters shall be provided for all key building services and energy usage of end users or tenants for energy consumption monitoring.

All electrical sub-meters shall be linked to the Building Management System (BMS) for energy consumption monitoring.

All lifts shall be incorporated with energy efficient features such as AC Variable Voltage Variable Frequency (VVVF) motor drive or equivalent OR/AND with sleep mode features or equivalent.

All escalators shall be incorporated with energy efficient features such as motion sensors.

Coverage of high frequency ballasts in the fluorescent luminaries shall be at least 90% of the applicable areas that are served by fluorescent luminaires.

Building shall be sited to preserve views, allow day lighting, shade common spaces, allow cross-ventilation, eliminate cross-contamination, and minimize site disturbances.

Passive design criteria for thermal comfort and health where building is configured to reduce glare and solar heat gain, induces clearly defined process and metrics for effective natural ventilation

Optimize massing within 20 degrees of an East-West elongation to reduce solar heat gain.

Envelope design guidelines – external shading approaches, glazing performance parameters, insulation performance parameters.

Design buildings to reduce or eliminate west-facing glazing.

Design shading to reduce heat gain and maximize daylight with the sun directly overhead. Recommend treatments that are most effective at east and west facades.

Optimize glazing selection for daylight penetration, balanced with reduced heat gain.

Utilize bulk flow analysis to create a standard for window opening and stack dimensions to allow for more effective and healthy natural ventilation to laboratory and patient care areas.

Utilize daylight sensors throughout to

eliminate unnecessary daytime use of electric light in non-patient care areas.

Provide for efficacious lighting design parameters such as controls, daylight integration, proper fixture spacing, proper wall and ceiling brightness.

Utilize zoning to create zones where passive strategies can be used without compromising lab or patient safety.

Provide systems performance baseline requirements for infrastructure and building equipment: Lighting, Ventilation, Cooling, M&V, escalators/elevators.

Provide systems design requirements for elimination of waste energy.

Base air changes per hour on air quality testing in the exhaust duct which detects parts per million of pollutants.

Campus Infrastructure:

Modular central plant to allow shut down of subsets of the equipment adjusting to reduce need.

Plan for an on-campus food waste composting plant for reducing waste hauling costs and to generate fertilizer biochar for use in the campus landscaping needs. Investigate potential for food waste to be an energy source through anaerobic digester to produce biofuel.

6 . 2 . 1 E N E R G Y E F F I C I E N C Y


NUS team is currently conducting a research & prototype on Biochar production and utilization. Organic wastes are used as input into a pyrolysis kiln where incineration occurs with low or no oxygen to produce Biochar and syngas. Depending on requirement, composition output of Biochar and syngas can be adjusted accordingly. Potential wastes from NUS for future development of this system are the food waste from canteen and waste from sewage pipeline. However, due to the risk of the toxic substances present in the sewage system from laboratories, focus at the moment will be on canteen food waste. NUS is currently generating sufficient amounts (25 – 45 tons per month) of food waste to run a pilot Biochar facilities in future.

The following sources and technologies are to be considered to meet the identified end uses where feasible.

End Uses

General breakdown of electricity consumption by end use in campus operations:

1) HVAC system: 55– 65%

2) Lighting system: 6 – 7%

3) Lift & Escalators: 2-3%

4) Lab equipment & others: 37– 25%

Technologies

NUS campus wide sustainability aim:

> To reduce NUS overall Green House Gases (GHG) by 23% against ‘business-as-usual’ level by 2020.

> To design and build energy efficient laboratories.


Chilled water thermal storage cooling

Ice thermal energy storage cooling

It utilises off peak electricity to produce cooling energy in either chilled water or ice.

> To reduce lab emission by 20%.

> New buildings to have energy efficiency increase by 25% compare to existing buildings.

> Existing buildings’ energy efficiency to be increased by 15%.

> To achieve at least 0.6kW/ton for HVAC system efficiency.

> Currently having <150k tons of CO2.

Following are the list of technologies and strategies that can be considered:

Exhaust Air Recovery

Recover cool exhaust air and direct to the cooling towers to achieve lower condenser water temperature. This would improve chiller efficiency.


Air-to-water heat pumps to be installed in place of conventional electric hot water systems to produce hot water for the showers.

Auto condenser tube cleaning system allows the chiller to maintain good heat transfer with constant cleaning of the condenser tubes.

UVC emitter can be installed after the cooling coils of AHUs and FCUs to keep the coils clean without the need for washing and chemical cleaning.

Electronic ballasts is a device intended to limit the amount of current in an electric circuit and operate fluorescent lamps in the high frequency

Heat Pumps

Air-to-water heat pumps are to be installed in place of conventional electric hot water systems which produce hot water for showers and discharges cool air at the same time. The cool air could be used as supplementary air conditioning for smaller air conditioned spaces or for pre-cooling. Cool air could be used to supplement some of the cooling load to reduce the chiller loading which will result in further energy savings.


Auto Condenser Tube Cleaning

Auto condenser tube cleaning system automatically cleans the condenser water tubes daily to prevent scaling and fouling. It reduces the frequency for regular tube cleaning and allows the chiller to maintain good heat transfer with constant cleaning of the condenser tubes. It is suitable for use in buildings with central air-conditioning system using of water-cooled heat exchangers or condenser.

Ultraviolet-C (UVC) Emitter

UVC emitter can be installed after the cooling coils of AHUs and FCUs to keep the coils clean without the need for washing and chemical cleaning. UVC emitter produces high output of UVC photons to destroy bacteria, viruses and mould. A case study by Florida Hospital showed that installing UVC emitter in AHU significantly reduced the need of coil-cleaning and also saved energy. UVC emitter in AHU provides continuous disinfection and coil cleaning.

High Efficiency Lighting

Installing T5 lamps instead of T8 lamps will yield the same illumination lux level but at a lower wattage level and giving a lighting budget of only 11 W/m2, meeting the lighting power budget based on SS 530.

High Frequency Ballasts

Electronic ballasts operate fluorescent lamps at a high frequency to increase the luminous flux of the lamp and reduce the operating wattage by 10%. These ballasts are able to reduce power losses (10% of lamp wattage).


Cool paints

Cool paints when applied on the roofs or exteriors of buildings can significantly decrease indoor room temperature and hence reduce cooling load required. Cool paints have high solar reflectivity as compared to conventional roofing materials or exterior surfaces. According to tests conducted by the University of Athens, the surface temperature of external surfaces coated with new generation cool paints are 6°C lower than the surface temperature of white marble. It is energy saving by reducing cooling load required and helps prolong the useful lifespan of the substrate, while providing the user with better thermal comfort.


Photocells / timers and Building Automation System for external lighting control

External light will be automatically turned on at dusk and turned off at dawn by the detection of day light. Singapore sunrise time varies from 6.46am to 7.17am and the sunset time varies between 6.50pm and 7.21pm. A comparison between conventional timer lighting controls set between 7pm to 7am against the use of photocell will yield an average of 2.41% in savings.

Strategic lighting, zoning, and controls

Separate switches to be provided for the perimeter lights near windows so that lights can be switched off when there is sufficient

ambient natural lighting. In large offices such as teachers’ rooms, lightings are grouped in zones and controlled by separate switches so that staff can have the flexibility of selecting a particular zone to be lit. This is useful when staff are working overtime or working during weekends when the entire office is not fully occupied.

Occupancy sensors/motion sensors

Energy is wasted when lights are left on in unoccupied rooms for prolong periods. Motion detector contains motion sensors that transform the detection of motion into an electric signal. It is commonly used to prevent illumination by detecting occupant motion and to only light the space when

it is occupied, especially spaces that have highly variable and unpredictable occupancy patterns, such as staircases, toilets, gyms, etc.

Light Shelves

Light shelves are sunshades placed inside or outside the window facade and above eye level to improve occupant views and comfort. They reflect sunlight and daylight into the interior space. They can also at the same time, shade the glass below and reduce unwanted direct glare. A sloped ceiling extending from the facade edge enhances light distribution and reduces contrast and glare. In addition, it reduces use of electrical lightings.

Sunshades placed inside or outside the window facade and above eye level. They reflect sunlight and daylight into the interior space. A flat-sloped ceiling extending from the facade edge enhances light distribution and reduces contrast and glare.

Significantly decrease indoor room temperature and hence reduce cooling load required, has high solar reflectivity as compared to conventional roofing material or exterior surface.


Self Cleaning Façade System

External cladding such as ceramic cladding with hydrotect (TiO2 – Titanium Dioxide) coating will provide self cleaning properties. The effect of hydrotect is based on the principle of the photo catalysis. Titanium Dioxide (TiO2) is a type of photo catalyst which can also be applied on the external facade such as glass, wall tiles and aluminum claddings to reduce the maintenance and cleaning of external facades. When exposed to sunlight, TiO2 absorbs a portion of the ultra violet light and becomes hydrophilic where water is not repelled but spreads to form a thin film on the surface. This enables the decomposition of bacteria, fungi, algae, germs and elimination of odors. With the combination of both photo catalysis and hydrophilic effect, substantial reduction in external facade cleaning costs can be achieved. Besides that, it also can eliminate odors in the air, kill bacteria and decompose organic matter when exposed to light. When exposed to light, TiO2 activates the oxygen molecules, which decompose bacteria and germs through photo catalytic activity. It is being used in commercial and healthcare facilities to improve the hygiene of its environment.


Variable Speed Drives

Variable speed drives are installed for cooling towers, kitchen exhaust fans, pumps, and air handling units. It reduces the motor frequency when the load on the equipment is low to conserve energy.

Regenerative Lift

The regenerative system recovers the potential energy accumulated when the lift goes down with a heavy load. Recovered energy can either be stored or be reused as another energy source.

Self Cleaning Facade System

Regenerative Lift


6 . 2 . 2 WAT E R C O N S E RVAT I O N

Future development and retrofits shall implement the following standards to improve water conservation:

To encourage reduction in use of potable water, all water fittings for the development shall be of Singapore Water Efficiency Labeling Scheme (WELS) EXCELLENT rating. This is applicable to all water fittings covered by the WELS as follows:

•Shower Taps & Mixers

•Basin Taps & Mixers

•Sink/Bib Taps & Mixers

•Flushing Cisterns

•Urinals & Urinal Flush Valve

•Showerheads

Water sub-meters shall be provided for ALL major water usage i.e. irrigation system, cooling towers and tenant’s usage where applicable.

All water sub-meters are to be linked to the Building Management System (BMS) for monitoring and leak detection. The BMS should have specific alert features that can be set and triggered to detect any water leakage during operation.

To reduce use of potable water consumption for irrigation, it is encouraged to use non-PUB water including rainwater and water efficient irrigation systems with features such as

automatic sub-soil drip irrigation system with rain sensor control wherever possible. These systems should serve more than 50% of the landscaped areas.

Where buildings are developed with water-cooled central chillers systems and package units, the specifications provided shall require design of water treatment for cooling tower to achieve at least six or better cycles of concentration at acceptable water quality.

Wherever possible, Newater or on-site and recycled water from approved sources shall be used to meet the water demand for cooling purposes.

Waste streams are to be treated and captured for reuse as a priority over the use of potable water, where potable water is not required.

Stormwater runoff rate, quantity, and quality are to meet pre-development stormwater conditions through landscape and building design.

To achieve these standards, the following Sources, Storage, and Applications are to be implemented where feasible.

Sources:

Stormwater: Annual rainfall approximately 2,370 mm (93 in). or about 6.5mm on average every day. Storage for reuse requires filtration.

Rainwater: Harvested rainwater to be used for

irrigation.

Condensate water: Recover condensate from FCUs / AHUs to supply into cooling tower to provide cooler condenser water to the chillers. This would improve chiller efficiency as well.

Wastewater – any reuse would require filtration to tertiary standards, through a recirculating biofilter, or a membrane bioreactor, or reverse osmosis (R.O.) water processors.

Water Utility – no storage or treatment required, and is best used for end uses that require drinking water quality.

Storage:

Design water reuse system at Academic Green podium so that treated water can be used immediately, with capacity of system increasing over time, and perhaps on a distributed basis to reduce pump energy cost/impact of distribution.

Sizing: Local code restricts water storage for reuse to a 2-day storage period, requiring that the specified tank be sized to meet only two days of projected demand.

Treatment: Prior to storage, all water flows will require treatment, both for quality (using a variety of available techniques) and for colour (using UV filtration).

Applications:

Landscape: heightening infiltration will reduce stream bank erosion downstream, and provide one means for filtration of runoff. Singapore ABC (Active, Beautiful, Clean) Waters Design Features are to be used to retain and treat runoff via natural means while enhancing the campus landscape. Green Roofs provide cooling, roof membrane protection, and reduce runoff.

Fountains: moving water can provide cooling to outdoor spaces, and can be operated with non-potable water.

Toilets/Urinals: this use is best met with non-potable water.

Mechanical make-up water: this use is best met with non-potable water.

Sanitary – faucets, cleaning: this use must be met with potable water.


Future development and retrofits shall follow standards to improve material efficiency:

Singapore Concrete Usage Index (CUI) is an indicator of the amount of concrete used to construct the superstructure which includes both the structural and non-structural elements. CUI does not include the concrete used for external works and sub-structural works such as basements and foundations. CUI is defined as the volume of concrete in cubic meters needed to cast a square meter of constructed floor area. It is expressed as:

To encourage more efficient concrete usage for building components based on the percentage reduction, Concrete Usage Index (CUI) should meet at least the baseline limit as show in the Table below and shall target for better control of concrete usage.

6 . 2 . 3 M AT E R I A L S E F F I C I E N C Y

Low volatile organic compounds (VOC) paints that are certified under Singapore Green Labeling Scheme (SGLS) shall be used for at least 90% of the internal wall areas.

Adhesive with low formaldehyde emission and that are certified under SGLS shall be used for all composite wood products used.

Existing buildings shall be utilized / reappropriated where possible without compromising function.

Maximize reuse of demolition waste. Only when campus reuse is not feasible should recycling or landfill be allowed.

Material guidelines – local, low-VOC, and resource-efficient (durable, recycled, renewable, FSC, etc) – Identify several bulk materials that can be purchased in contract over time cost-effectively and with minimal materials research investment. Singapore Green Labeling Scheme lists materials available locally. Please refer to the list of SGLS materials in the Appendix Chap 9.7.3.

Adequate area shall be set aside for appropriate waste management measures: composting, recycling, medical/hazardous wastes, etc, to ensure safety and waste minimization.

6 . 2 . 4 E N V I R O N M E N TA L P R O T E C T I O N A N D Q U A L I T Y

Future development shall use the following standards to improve the campus environment:

Eliminate vehicle traffic in the campus core, for health, safety, comfort, and air quality reasons.

Enhance plant and animal species diversity on the campus.

Provide shaded and breezy outdoor spaces with superior comfort in all climate conditions

To achieve these standards, the following strategies are to be pursued where feasible:

a) Create a pedestrian campus by moving vehicular traffic and parking to the campus perimeter and providing efficient, clean, and convenient transit for circulation through the campus and to the Mass Rapid Transit (MRT).

b) Common level connected walkways provide a flat common platform for safe cycling on level terrain. Bicycle storage and shower facilities to be provided for cyclists and other public use. In addition, bicycles available for rent on campus might improve connection to MRT arriving at campus from off campus.

c) Enhance habitat corridors - Habitat corridors will be created within the ‘forest fingers’ cascading from the Ridge to the green academic core.

Provide adequate open space with a diversity

CUI Limit for Non-Residential Building

of native plants that support urban fauna.

Eliminate exhaust air blowing into pedestrian areas.

Ensure that exhaust stacks are positioned correctly to eliminate re-entrainment of exhaust into neighboring buildings

Site shall be designed to ensure thermal comfort at the outdoor spaces – shaded, with air movement, and natural cooling, perhaps with water wall technology.


PART 1 – ENERGY EFFICIENCY Master Plan Green Mark Implementation6 . 3 G R E E N M A R K D I S T R I C T

N

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PART 1 – ENERGY EFFICIENCY6 . 3 G R E E N M A R K D I S T R I C T

Calculation included only theorientations of the proposednew buildings


PART 1 – ENERGY EFFICIENCY6 . 3 G R E E N M A R K D I S T R I C T

To aim for chiller efficiency of not

capacity is required.


PART 2 – WATER EFFICIENCY Master Plan Green Mark Implementation

Label for Products Under Mandatory WELS

Label for Products Under Voluntary WELS ABC (Active, Beautiful,

Clean Waters)Strategy

6 . 3 G R E E N M A R K D I S T R I C T


PART 2 – WATER EFFICIENCY Master Mediapolis Master Plan Green Mark Implementation

Drip Irrigation

Rainwater HarvestingRainwater Harvesting is a collection of rainwater into a central tank to be used for irrigation. Water collected from the tank will be supplied and used for irrigation.

A system of crop irrigation involving the controlled delivery of water directly to individual plants through a network of tubes or pipes.



PART 3 – WASTE MATERIAL MANAGEMENT

SGLS Linoleum Flooring Brick & Concrete Pavers with Recycled Content



PART 3 – WASTE MATERIAL MANAGEMENT6 . 3 G R E E N M A R K D I S T R I C T


PART 4 – ENVIRONMENTAL PROTECTION

Sectional View of a Permeable Paving System – Assist in Reduction of Stormwater

Covered Walkways

Campus Car Parking

Section View of a Permeable Paving System Assist in Reduction of Stormwater



PART 4 – ENVIRONMENTAL PROTECTION6 . 3 G R E E N M A R K D I S T R I C T


PART 4 – ENVIRONMENTAL PROTECTION6 . 3 G R E E N M A R K D I S T R I C T


PART 5 – OTHER GREEN FEATURES

Biochar


Non-chemical water treatment system


NUS/NUHS Green Mark District Pre - Assessment Scoring Summary

1. ENERGYEFFICIENCY

Green Mark

TryAgain Certified Gold GoldPlus Platinum

Score 0 49 50 74 75 84 85 89 90 100

2. WATER EFFICIENCY

3. ENVIRONMENTALPROTECTION

4. INDOOR ENV.QUALITY

5. OTHERGREEN FEATURES

15.75

7

1.5

Energy Score

Other Green Features Score

Estimated Green Mark Score45.60 32.25

8

77.85



6 . 4 A I R F L O W S T U D I E S & R E C O M M E N D AT I O N S

Computational Fluid Dynamics (CFD) Studies

CFD Study has been carried out using the master plan phase one 3D building model to simulate the prevailing south wind case airflow at the proposed master plan site. The sample results obtained are illustrated in the diagrams at right.

The airflow on the academic green plane shows greater windflow at the gateway and opening between the buildings, and low wind speed at some areas of the covered linkway and near to building entrance.


6 . 4 A I R F L O W S T U D I E S & R E C O M M E N D AT I O N S

Recommendation

Each A&A proposal and new building is to address 2 key ventilation concerns.

a) Impact of exhaust from adjacent buildings and from the new building.

b) The need to encourage flow of natural cross winds for thermal comfort at the Academic Green level.

CFD study using an accurate 3D building massing is required to ensure that possible pollutants are channeled away from air intakes and naturally ventilated occupied areas.

Any new building form shall be configured to ensure proper airflow whereby possibly polluted air is channeled above the building to be diluted above roof level while clean prevailing winds are captured at mid level and scooped down to the Academic Green level to increase thermal comfort.

The naturally cross ventilated areas are to comply with the recommended airflow of 0.6m/sec at the height of 1.5m above the occupied space. Under certain ambient conditions, it is possible for wind speeds as low as 0.3m/s to contribute to thermal comfort as well. Some of the open areas which have covered walkways and are near to building entrances may not require high wind speeds as strong breezes induce the wind driven rain.

Airflow at proposed FoS1 building area showing the air is chanelled above and below through the gateway of the building.

The airflow diagram illustrates the wind path above and between the buildings.

SUSTAINABILITY - National University of Singapore

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