Instead of completely demolishing the old structure and repouring foundations, the new center was located on the site of the original building and used the existing foundation of an old pump house and the buried tank walls of the decommissioned sewage treatment plant. A concerted effort was made to eliminate waste related to construction, with recycling bins set up on the site for materials such as wood, metal, glass, asphalt, and concrete.
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The new wood-frame building includes reclaimed heavy timbers and roof decking. A trellis screening the west-facing office pavilion is constructed of recycled telephone poles. Use of recycled materials in the design also included rubber flooring, insulation, gypsum board and carpet.
All new concrete, including the cementitious wall panels, contain an average of 40-percent fly ash. In total, 8 percent of the building products contain either postconsumer waste, postindustrial waste, or a combination of both.
The architects also made a conscious effort to select locally produced materials, where possible, to reduce the energy consumed in transporting building materials to the construction site. All cladding, for example, was locally harvested and milled West Coast cedar. As a result, more than 31 percent of the materials were procured from manufacturers within a 500-mile (805-kilometer) radius of the site.
The variety of sustainable strategies employed at White Rock is expected to reduce site water use by approximately 90 percent and building and process water use by at least 30 percent. It is also anticipated that approximately 546,000 gallons (2 million liters) of potable water will be conserved annually.
Through these combined efforts, a reduction in energy consumption is expected to be 60 percent better than the Canadian Model National Energy Code for buildings (and 50 percent better than ASHRAE 90.1-1999). Energy-efficient strategies for mechanical and electrical systems are also expected to save approximately Can$5,000 per year. The additional cost for high-efficiency systems will be paid for in just eleven years, after which time these strategies will continue to provide operational savings to the client.
With temperatures in White Rock averaging 73.4 degrees Fahrenheit (23 degrees Centigrade) during the summer and 42.8 F. (6 C.) in winter months, KEEN and the architect collaborated on designs that allow the building to maintain a comfortable environment with passive systems. The mechanical systems are minimal; where used, they are exposed for easy access and maintenance.
Because the building form was somewhat predetermined (reflecting the plans and geometry of the existing buried tank walls on site), the designers specified glazing and solar protection treatments that would respond to the structure's orientation relative to the daily and annual solar path.
As a result, north elevations have less than five percent glass, and office areas (to the south) have walls with 50 percent glass. East-facing windows are protected by a large roof overhang and deciduous trees. South windows are protected by a roof overhang and solar shades. West-facing windows are screened by a trellis that supports vines.
The building's office area was designed as a narrow bar — a small dimension to the south and larger dimensions east and west — which accentuates cross-ventilation. As a result, all occupants sit adjacent to operable windows for natural light and ventilation, and cooling loads are reduced (with no mechanical air conditioning). A green roof on the top of the office further reduces heat gain.
The two-story component of the building features a white, low-albedo roof to reflect heat. Inside, KEEN designed a heat recovery ventilation system that "boosts" airflow, heating, or cooling as needed during the day in transient spaces such as when field staff use the changing rooms in the morning, at lunch, and at the end of the work day. In effect, the ventilators rise up to provide the necessary airflow requirements and then drop back down into "sleep" mode.
The building design also features active solar strategies to conserve energy and minimize air emissions. Systems include solar hot water tubes, radiant in-floor heating, and a solar-panel array demonstration project that generates approximately 5 percent of the building's energy requirements.
The project's water conservation and stormwater strategies were equally innovative. The abandoned concrete storage tank of the treatment plant presented a unique opportunity for stormwater storage and reuse. The city's engineering group came up with the idea of redirecting some existing storm drainage lines to discharge through the large, round 130,000-gallon (491,000-liter) storage tank.
Given the region's high annual rainfall, that idea represented approximately 3.7 million gallons (14 million liters) available for irrigation, flushing toilets, washing municipal vehicles and filling street-washing vehicles. KEEN recommended the addition of a water-source heat pump, which then utilizes water in the tank to provide heat to the building.
Security and dependability of the energy supply for the new center were addressed in several ways. The building uses a number of low-tech strategies and technologies, reducing its dependency on energy from off-site sources. The site is serviced by an on-site emergency generator, so the building will be able to function independent of the grid. The City of White Rock bought green power certificates for all of the remaining annual energy requirements.
And finally, when construction was complete, KEEN and the team's other engineers carried out complete commissioning on the building to ensure that systems were operating according to the design intent.
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David R. Macaulay is a freelance writer who specializes in architecture, engineering, and construction. He has served as editor of two national trade magazines covering the water and construction industries and as writer/ publisher for an international facilities engineering society. Jason F. McLennan is CEO of the Cascadia Green Building Council and an activist in the green architecture movement. He is a founder of Ecotone Publishing, dedicated to educating design professionals about the impact of the construction industry on the environment.
This article is excerpted from The Ecological Engineer, Volume One: KEEN Engineering, copyright © 2005, available from Ecotone Publishing and at Amazon.com.
Owner: City of White Rock, British Columbia
Architect: Busby Perkins+Will
Mechanical engineer: Keen Engineering
Structural engineer: Fast + Epp
Electrical engineer: Flagel Lewandowski
Landscape Architecture: Wendy Grandin/Viewpoint Landscape Architects Ltd.
Indoor Air Quality: Pacific Environmental Consulting Services
Cost: Helyar & Associates
General Contractor: KDS Construction, Ltd.