Matsusaki Wright Architects
pp 11-14, Design for a New Millennium,
ed. E.Laquian (1995) . Institute of Asian Research, Vancouver.
At the onset of the 21st century, the world faces global warming from greenhouse gas emissions, a thinning ozone layer, depletion of natural resources, an inadequate supply of fresh water and reduced capacity for food production. All of these issues are exacerbated by a steadily increasing population. "Our human values and institutions have set mankind on a collision course with the laws of nature" (Human Ecology: Problems and Solutions Ehrlich, Ehrlich, Holdren). In 1993 when the University of British Columbia commissioned Matsuzaki Wright Architects for the design of the C. K. Choi Building, a mandate was set to attain a new benchmark in sustainable design. The project team was composed of:
Architects: Matsuzaki Wright Architects Inc.
Structural Engineers: Read Jones Christoftersen
Mechanical Engineers: Keen Engineering
Electrical Engineers: Robert Freundlich & Associates
Landscape Architect: Cornelia Hahn Oberlander
Landscape Contractor: North by Northwest Landscape
To achieve the goal of sustainable design, the project team challenged industry standards at every step of the project. From their own design process to University standards, each decision was assessed for both its immediate and long term impact on the environment. Four key issues addressed by this project are:
Reducing Impact and Consumption
The component of this building that has piqued the most interest is unquestionably the use of composting toilets. From a water conservation perspective, the system not only saves all the water that would be used for flushing a conventional toilet, it also reduces the wastewater volume sent to the sanitary sewer system by a similar amount.
This waterless toilet system enabled the building to be disconnected from the sanitary system. An objective of the continually ventilated composting toilet system is to reduce the volume of waste by up to 90%, and produce a humus-like product that is rich in nitrogen and other useful elements. Researchers and operations staff have monitored the system since installation and have found that while these toilets have achieved their water conservation objectives, the solid and liquid outputs that are produced need to be handled differently than originally intended in order to destroy potential pathogens.
Embodied Energy in Construction
Reused heavy timbers from the Armouries building previously located across the street and reused red brick cladding from the streets of Vancouver give the Choi Building an aesthetic that is rich in history and energy efficiency. Many additional reused and recycled materials are also incorporated in the building. (See Appendix A in book)
The exact total of energy saved from extraction, transportation, refining and production of these materials has not yet been tallied. This number is expected to be substantial as it is estimated that more than 50% of the total materials are reused or recycled. Benefits in reduced greenhouse gas emissions are important as are the savings to the earth's limited supply of natural resources.
Operating Energy Over Time
Inside the Choi Building, spaces are so filled with daylight that the power consumption for lighting is less than half that required for typical office buildings. Offices have manual light switches; however, controls systems dim lights if adequate daylight is available or turn off lights if a room is vacant.
Operating energy is also reduced by the elimination of a traditional ducted air system. The building relies on natural ventilation with a few fans to assist when necessary. Operable windows and fresh air vents under each window allow a continual flushing of fresh air through the building. The cool fresh air rises as it warms through a series of high atria. When the warm air exits the building through louvres high in the atria, fresh air is simultaneously drawn in through the window vents. In total, the energy saved from the Choi Building in one year will power four Vancouver residences. (See Appendix B in book)
Liveable Working Space
For any building to achieve longevity and in turn be sustainable, it must be a place where people like to work or live. The occupants of the Choi Building enjoy natural daylight to work in and 100% fresh air at all times. Air quality within the building is improved through careful selection of building materials, finished products and construction practices. For example, the carpet is laid without adhesives, millwork is constructed from formaldehyde-free materials and finishes are solvent-free, low emission products. Features such as direct venting of the copy machines areas help to maintain good air quality over time.
As a leader in the community, the University of British Columbia sets goals and values for the community to emulate. The C. K. Choi Building is an example of a sustainable approach in the building industry. It is rewarding to see that interest to date has come from not only the local community but also from many corners of the world. As the construction of this project is finished, it is now those who will occupy and maintain the building who will face the next challenge of this project: to set new standards in sustainable operations.
The C. K. Choi Building has won the 1996 Building Owners and Managers Association's Earth Award. The BOMA Earth Award is a new opportunity to recognize and promote "environmental friendliness" in commercial buildings. The following environmental aspects of the building were considered for the award:
Energy Usage: Based on a Building Simulation Energy Study, this 30,000 sq. ft. office building exceeds its Ashrae 90.1 prototype building by 57%. The total electrical savings are 191,603 kWh per year. For this achievement, B.C. Hydro provided a $44,121 incentive to the Owner under the New Building Design Program. Some of the key energy savings features include: retaining an existing stand of trees along the 300 foot western edge of the building to reduce cooling loads; utilizing building forms that enhance internal stack effects to provide air change through natural ventilation and localized fans (no large mechanical air handling system); utilizing building forms that enhance daylighting to reduce reliance on electric lighting and reduce cooling loads; incorporating daylight sensors and occupancy sensors to minimize unnecessary use of lights; incorporating high efficiency luminaries with lower ambient lighting levels and task lights where appropriate; exceeding the R-values suggested under Ashrae 90.1 for walls, ceiling and glazing; careful attention to detailing and construction methodology to minimize heat loss through thermal breaks etc.; utilizing waste heat in an existing steam vault adjacent the site to preheat domestic water. (See Appendix C in book)
Water Conservation: Significant water savings are realized through a series of features. Composting toilets installed in this project do not require water for flushing. City water is generally only required for the low flow lavatory faucets (spring loaded to further reduce waste) and kitchen sinks. Collected rain water (stored in an 8,000 gallon subsurface cistern) provides irrigation for site landscaping. Projected water usage is approximately 300 gallons per day.
Waste Management: Sanitary wastewater is reduced through the use of the composting toilets. The composting toilets dramatically decrease the amount of wastewater that is sent to the sanitary sewer from the building. To manage the risks of pathogens from the composting toilets, the partially-composted contents of the toilets are periodically pumped out for separate processing off campus. The small amount of excess liquid generated is sent to the sanitary sewer. Based on experience to date, pumping out is expected to be required no more than every 18 months. In the original design, the plants and microbial community of the outdoor greywater recycling trench were used to treat greywater collected from sinks for irrigation. Because greywater from sinks is collected together with liquid from the toilets, the greywater is now also sent to the sanitary sewer. Water from the subsurface rainwater holding tank is fed to the greywater recycling trench to ensure that the plant life in the greywater trench is never left dry.
Construction Waste Management: The significant amount of reused materials and products with recycled content in this building (60% of primary wood structure, 100% of exterior brick cladding) address waste management by diverting materials from landfills. In addition, a comprehensive waste management plan was implemented during construction. The site separated and recycled waste materials diverted more than one half of the waste generated on site from the landfill.
Ozone-Depleting Substances: In addition to being free of CFC's as required under provincial regulations, efforts were made on this project to select systems and products that minimize impact on the ozone layer. For example, rigid insulations are expanded boards foamed with pentane (not ozone depleting) versus extruded boards expanded with an HCFC, and natural ventilation eliminates the need for refrigerated coolants. The significant amount of reused and recycled materials in this project also greatly reduces the use of fossil fuels (otherwise required to extract, transport and process new raw materials) and thus reduces carbon dioxide emissions, the largest single component of current greenhouse gas emissions.
Indoor Air Quality: Three strategies were taken to ensure good indoor air quality. Material selection was carefully reviewed. For example, all millwork is constructed from formaldehyde-free medite, all finishes are solvent-free, low VOC products, carpet is laid with a tack strip method versus adhesives. Construction sequencing was specified to ensure flushing of the building during drywall installation and finishing, painting, caulking, and during the installation of carpets. As people produce carbon dioxide and everyday operations add VOC's to buildings, the natural ventilation system in the building was designed to provide 20 cfm per person of 100% fresh air at all times. In addition, copy machine areas are direct vented. Being continually flushed, the building does not experience peaks and valleys in lAO often found in traditional mechanized systems that operate with reduced air changes during low occupancy hours.
Building Waste Management: The Choi Building incorporates a comprehensive approach to management of building waste and surface water on site. Graywater is collected in the building and directed to an exterior subsurface graywater recycling area. The graywater recycling trench contains plant material and in turn, microbial plant life known for their capacity to neutralize bacteria in the graywater. The recycled graywater is then used for site irrigation. A subsurface holding tank is incorporated for storage of rainwater collected from the roof area. This water is used for summer irrigation of the site and to ensure that the plant life in the graywater trench is never left dry. This design results in no city service connection for graywater waste from the building and no use of city water for site irrigation. The addition of composting toilets to this system allows this building to be "off grid" for sanitary waste.
Environmental Management: The first step in environmental management was to enhance the ambient conditions of the existing site. Existing trees were retained for their capacity to remove C02 from the air and the shade they provide on the west elevation. The building replaces an existing parking lot and the dynamic building form capitalizes on the benefits of the different climatic conditions at each orientation. The second stey was designing a building that minimizes consumption and impact on the environment. The total operating energy savings for this project are 50% greater than what is achieved under the new Energy By-Law of Vancouver. An energy meter enables the building owner and users to monitor actual energy use in the building and make adjustments in operations as necessary.
Tenant Awareness Program: Part of the commissioning process of this project includes educating users about building features and items over which they have control. For example the building has operable windows and user control over heat in work spaces. Understanding the way the stack effect for ventilation works or the operation of daylight and occupancy sensors, enables the users to participate in energy efficient operations and ensure that good IAQ is maintained.