Green Mark Standards And Criteria Construction Essay

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Points scored for the criterion in relation to Ventilation in Carparks is awarded as long as there is ventilation within the carpark, whether it is through natural or mechanical means, and regardless of the extent of ventilation. This particular point system can be seen to be inadequate as it allows for this point system to be easily abused by the awardee. This is because points will also be awarded to buildings with carparks that remain stuffy due to a minimal extent of ventilation just so to meet the criterion of having ventilation within the carpark. This would defeat the rationale of the Green Mark [2] , which is to drive Singapore's construction industry towards more environment-friendly buildings. Therefore, our team is of the opinion that the point awarding basis for this criterion can be revised to a basis similar to that of NRB 1-8 Ventilation in Common Areas1 of the Standard, where the extent of coverage must be at least 90% of each applicable area. It would be more appropriate and reasonable to add an additional requirement of a certain extent of coverage in order for points to be awarded under this section. Also in RB 1-7/NRB 1-10 and RB 1-8/NRB 1-11 that awards buildings for their use of Energy Efficient Features1 and Renewable Energy1 respectively in relation to energy savings, the objectives are to encourage the use of green features that are innovative and have positive environmental impacts. Our team is of the view that it is important that new buildings should incorporate the best recognized practices suggested in the requirements under the standard, and find that the grading system may be insufficient in encouraging and pushing for the desired result as it is only acting as a bonus component. Hence, our team suggests that this part of the standard should be made a prerequisite requirement. For example, to achieve a Green Mark GoldPlus or Platinum, the building should achieve 50% of the points allocated for this criterion.

Under Water Usage and Leak Detection1 (RB 2-2 /NRB 2-2), points are allocated with any provision of private water meter to better manage water usage. However, considerations for the actual adoption of such private meter should be included. The purpose of the water meter is to measure usage. The organization may have it installed but may not utilize these measuring devices, which will defeat its objective. A suggestion will be to enforce the application of water meters. The organization should have a management plan to record the readings regularly and compare water consumption figures to monitor any abnormal or significant increase in water consumption. If there is any abnormal peak, investigation and rectification should be carried out to effectively tackle on unsatisfactory water consumptions. The authority will review log books or journals as documentary evidences. Singapore's water resources are very scarce and 50% of the land had been used for water catchment. As compared to other components in the framework, the point weightage allocated under water efficiency seems to be insignificant. Therefore, more emphasis on its importance should be placed on Water Efficiency by increasing the influence of the scheme.

Under the category for Environmental Protection, one of the flaws identified is that the directives given are unclear with regards to how the points are awarded. For instance, on Environmental Management Practice1 (RB 3-4/NRB 3-4), points are awarded as long as environmental friendly programmes are carried out with targets in place and proper monitoring. However, there is no explicit measurement on the effectiveness of the programme. Thus, there may be possibility of low or easily attainable targets set to earn the point. In addition, points are awarded so long recycling bins or similar facilities are provided. With no reference to the required number of bins to be provided, this may defeat the purpose of the need for recycling facilities in the building. Points are also awarded for buildings with good access to public transport network1 (NRB 3-5 Green Transport). However, this criteria may be inadequate as it does not take into consideration the accessibility to public transport network which may be available in future. This is especially so for non-populous land sites released for development where very often public transport is not readily available yet and as such, points will not be awarded during the Green Mark assessment.  Therefore, to improve on the criteria, our team suggests that a minimum target for the environmental friendly programme is to be achieved in order to earn the point. For points awarded for recycling facility, a suggestion is to have a minimum number of bins based on an estimate of the number of recyclables that will be generated [3] . Lastly, points would still be awarded to buildings with no readily accessible public transport network as long as there is evidence that public transport will be accessible in near future, for instance evidence from the Singapore Master Plan [4] .

Under NRB 4-3 Indoor Air Pollutants1, the criterion only requires the use of certified paints and adhesives in their aim to minimise airborne contaminants. Our team feels that this category with respect to non-residential buildings should not be limited to these two items and should consider other items as well. One example will be to identify carpets with very low emissions of volatile organic compounds (VOCs) to help improve indoor air quality, as many non-residential buildings use carpets, especially in offices. Upholstered furniture and pressed-wood products should also be considered as they can emit formaldehyde, which is a probable carcinogen that can also cause irritation, skin rash and severe allergic reactions. Requirements in this criteria should therefore be more comprehensive to ensure that indoor air pollutants are minimized. Points are awarded for the provision of filtration media and differential pressure monitoring equipment in Air Handling Units (AHU) under NRB 4-4 Indoor Air Quality (IAQ) Management1. This issue is similar to that of the water efficiency criteria as stated above, where objectives may be defeated when equipment provided are not utilized effectively. A management plan should therefore be implemented to ensure that the monitoring equipment are efficiently used, contributing to proper indoor air quality management.

Part 5 (Other Green Features1) of the Green Mark standard awards buildings for their use of green features and innovations in relation to water efficiency, environmental protection, and indoor environmental quality under other green requirements. The objective is similar in RB 1-7/NRB 1-10 and RB 1-8/NRB 1-11, and the issue identified along with the solution is discussed under energy efficiency above. On top of that, our team found that points are awarded for the calculation of carbon footprint for building development under this part of the standard. Our team is of the opinion that the calculation should be considered as the required documentary evidence in the awarding of points under RB/NRB 3-1 Sustainable Construction1 and the awarding of points under this part of the standard is not necessary as it would only make the points easily attainable.

Reasons for choice of building

After deliberation within the team, we have chosen Gardens by the Bay ("the Gardens"), a special non-residential building. The reasons for our choice are discussed as follows:-

Our team was first and foremost attracted by the significance of this development. The Gardens is a major investment of $1 billion by the government to integrate nature within a built environment and is also the first of its kind. Being a popular tourist attraction in Singapore, the Gardens contributes to a bulk of the tourism industry. The Gardens can also serve as a place for urban outdoor activities and provides additional recreational opportunities for our increasingly urbanized population to experience nature. The Gardens has been designed with the environment in mind; adopting environmentally sustainable technologies. The cooled conservatory complex had also won the World Building of the Year at the prestigious World Architecture Festival 2012. The Gardens is built on reclaimed land and contributes significantly as a green oasis in the heart of Singapore's new fascinating downtown district to live, work and play in. An endorsement of Singapore's progression and efforts to contend internationally in every field, the Gardens is an impressive piece of work and has become a national landmark. As a visionary combination of environmental science, architecture and landscaping, the Gardens have to be heralded as a feat of engineering and planning. With these various unique characteristics, our team has thus decided on the Gardens as our choice of building.

Five sustainable features implemented by Gardens by the Bay

Horticultural waste from parks around Singapore are usually sent to landfills. The Gardens collects these waste along with those from the individual gardens within the Gardens itself and burns it in its biomass boiler to generate heat and steam. The heat is used by absorption chillers to generate chilled water, while the steam drive a Combined Heat Power (CHP) steam turbine [5] to generate electricity that powers the electric chillers which are used to cool the two Conservatories. The use of biomass5 to generate electricity is considered a renewable source of energy and is therefore likely to earn points for the Gardens under NRB 1-11 Renewable Energy1.

The Supertrees5 at the Gardens are not designed only for aesthetic purposes, but also to collect renewable energy from the sun. Photovoltaic panels are built on the top of these Supertrees, which can gather more than 100kWp during the day. This energy from the sun is used to light up all the Supertrees in the night. Furthermore, the photovoltaic panels are built using silicon that is abundant on earth - this is yet another sustainable feature within the Supertree itself. Points were therefore likely to be awarded under NRB 1-10 Energy Efficient Practices & Features1 and NRB 1-11 Renewable Energy1. The Supertrees, being a unique innovative feature both aesthetically and in terms of environmental-friendliness would have probably scored under NRB 5-1 Other Green Features & Innovations1 as well.

Dragonfly Lake5 is designed for sustainable water cycle throughout the garden and also acts as a retention pond for stormwater management. Aquatic plants act as natural eco-filter to cleanse water before being discharged into Marina Reservoir. It is a natural method of nutrient removal of nitrogen and phosphorus and help to minimize algae boom and enhance water quality. Habitats for fish and dragonfly are created within the system to maintain a diversity of aquatic plants, good water circulation and aeration which prevent potential problem such as mosquito breeding. The natural water treatment utilizes rainwater which is collected from the lake's surface as well as the slanting structure of the conservatories. The use of aquatic plants also contributes to minimum irrigation. The Gardens would therefore earn its points through NRB 2-3 Irrigation System and Landscaping1 with the use of non-potable water and NRB 3-7 Stormwater Management1 with its collection and treatment of stormwater run-off.

Being a garden, the paramount importance is to ensure that sufficient sunlight reaches the plants in the conservatories while reducing solar heat gain during hot weather. As such, the conservatories [6] are constructed in a gridshell and arches structure to allow maximum light possible to reach the plants in the conservatories. Ribs of the conservatories are also painted white to reflect light and heat. Specially selected glass panels are also used in the structure of the conservatories. These glass panels allow optimal light transmission while minimizing solar heat gain with its low solar heat gain coefficient. On top of that, the roof is also fitted with a sensor-operated retractable sails, which are concealed within the arches, to provide shade and minimize heat gain when necessary. The design of the conservatories also helps to conserve heat with a high volume to small surface area design during rainy weather. The conservatories are also designed to tilt towards Marina Bay to be in the north façade so that it is self-shaded and does not receive the full glare of the sun. The design of the building and use of the specially selected windows are likely to contribute to NRB 1-1 Thermal Performance of Building Envelope - ETTV1 where heat gain is minimised and thus cooling load requirement is reduced, as well as NRB 1-5 Daylighting1 where minimal artificial lighting is required, thus reducing the need for energy use.

The cooling process is especially important in the Flower Dome as a cooler temperature is required for the growth and survivability of the flowers that would not have survived the hot climate in Singapore. The use of a liquid desiccant system5 de-humidifies the air in the Dome while cooling it so that lesser energy is required in the cooling process. This will constitute to significant energy savings in the long run, as such, the system will contribute to the Green Mark scoring under energy efficiency. Additionally, the liquid desiccant (drying agent) is recyclable when moisture is removed by using the waste heat from the burning of biomass, and thus also contributing to the Green Mark scoring under the use of sustainable products1 (NRB 3-2).

Four sustainable features that could have been reasonably implemented

Covered walkways are scarce at the Gardens and there is none that links it to the nearest MRT, which would otherwise earn an additional point under NRB 3-5 Green Transport1. The purpose of such a covered walkway is to promote the use of public transport which is greener and more sustainable. Additionally, solar panels can be installed on top of the covered walkways, allowing greater energy savings with the use of renewable energy, scoring points under NRB 1-11 Renewable Energy1.

Lifts and escalators at the Gardens constantly run even when there are no visitors using it, resulting in a waste of energy. Therefore, our team suggests the installation of Variable Voltage Variable Frequency [7] (VVVF) motor and sensors. In lift applications, VVVF control regulates input voltage and frequency to the motor throughout the journey. As compared with other motor drives, it draws much less current during its operation. In escalator applications, it can be incorporated with automatic motion sensors or automatic two-speed control to vary the escalator speed according to the passenger flow. Since the operation of these escalators is determined by the absence or presence of passengers, energy can be saved when the escalator is idle. By installing the VVVF motor and sensors, it saves energy without affecting the convenience it provides to the visitors. Furthermore, it reduces wear and tear, thus increasing the lifespan of these facilities. Therefore, the VVVF motor and sensors can be reasonably implemented and additional points can be earned under NRB 1-9 Lifts and Escalators1.

Hybrid carpark lots is recognized as one of the key features in the BCA Green Mark award. Points are also awarded for the provision of electric vehicle charging stations under NRB 3-5 Green Transport1. The Gardens provides family carpark lots, which is catered for big family cars. However, it does not have hybrid carpark lots which gives priority to hybrid car users. By having hybrid carpark lots, the Gardens encourages the use of hybrid electric cars, which contributes to environmental sustainability due to its fuel-free characteristic. This could have been reasonably implemented as they only have to set aside a few carpark lots for hybrid cars.

As of now, the facade of the domes are manually cleaned  by cleaners. A more sustainable way of cleaning is the use of a self-cleaning facade system [8] , that can be motorized or by the coating of chemicals on the glasses. The motorised self-cleaning facade system is activated by rainfall and uses the rainwater to clean the facade. The other method which coats chemicals, Titanium Dioxide (TiO2), on the glass panes utilizes the sunlight adsorbed to form a "protective" layer that decomposes bacteria. As such, our team recommends the use of the motorised system as it would not interfere with the adsorption of sunlight by the plants in the dome, even though both types of the system will contribute to the scoring under water efficiency and other innovative green features.