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September 20, 2007
The relationship between sustainable buildings and conservation has long been understood: the use of renewable resources conserves natural environments for plants, animals and human enjoyment, while sustainably designed buildings use less energy, reducing our dependence on the fossil fuels that cause global warming.
The financial and social benefits for the owners of green buildings have also recently gained attention as an increasing number of sustainably designed buildings have been constructed and their performance documented and studied.
Sustainably designed schools have received attention recently, as a new report documents compelling financial, academic and physical health benefits of green schools.
The 2006 report “Greening America’s Schools: Costs and Benefits” by Capital E, a green-building consultant, documents the following compelling advantages of building green schools:
• On average, green schools save $100,000 each year over non-sustainably designed schools (enough for an average school to hire two additional full-time teachers).
• A sustainably designed school can increase standardized test scores within a student population by three to four percentage points.
• With improved lighting, temperature control, ventilation and indoor air-quality, green schools reduce the incidence of asthma, colds, flu and absenteeism of students and teachers.
These results build on earlier research completed in 1999 and reconfirmed in 2003 by the Herschong Mahone Group, which found that there is a statistically compelling connection between daylighting and student performance.
Students with the most daylighting in their classrooms scored 20 percent higher on math tests and 26 percent higher on reading tests in one year than students in the classrooms with the least amount of daylighting. These effects were observed with 99 percent statistical certainty.
Additionally, children are more vulnerable to environmental contaminants than adults because their bodies are still growing and developing, and their immune systems cannot fight off infectious organisms with the same ability as adults. Exposure to common molds and damp environments has been associated with childhood respiratory illnesses such as allergies, bronchitis and asthma.
A lack of proper ventilation can lead to a buildup of carbon dioxide and other indoor pollutants, which can lead to behavioral problems, headaches and fatigue, in turn diminishing a student’s ability to learn.
Daylight and ventilation
Although a green building is a complex puzzle with many pieces, lighting a school building through the use of daylight, and ventilating (heating and cooling) it with natural breezes, is the backbone of any sustainably designed school.
BOORA Architects has long appreciated the ability of daylighting and natural ventilation to reduce energy use and energy costs.
Buildings designed by the firm include Clackamas High School, the first LEED-certified high school in the country, and The Dalles Middle School, both in Oregon. These buildings have shown minimum reductions of 42 percent and 43 percent, respectively, in energy consumed, largely through daylighting and natural ventilation.
Daylighting is a strategy for lighting the interior spaces of a school by capturing sunlight present during the daytime and directing it to the interior spaces of the building.
Similarly, natural ventilation captures fresh outdoor air and brings it into the building to ventilate its interior spaces. In both cases, traditional means of lighting and ventilating through energy-intensive light fixtures and motorized fan-supplied air vents are replaced by nature’s bounty.
The most exciting and interesting challenge in designing daylit and naturally ventilated schools is the opportunity to integrate the two systems.
While a building can be daylit without being naturally ventilated and vice versa, we prefer to integrate daylighting and natural ventilation systems because an integrated approach realizes greater efficiencies than can be achieved when the two systems are designed independently.
The trick to integrating these systems is to provide an extremely efficient natural ventilation system in buildings that are daylit. As their name suggests, daylit buildings derive light from the solar radiation of the sun. In addition to supplying light, solar radiation also supplies heat.
If we get heat along with the daylight we bring into a building, then we have to engage an energy-intensive fan-driven ventilation system to cool the building. However, buildings can be designed in a way that draws in as much daylight as possible while still keeping the building cool.
If a building’s designers understand the process of convection, by which heated air rises and creates a vacuum behind it into which cool air is drawn, a school can be designed to be substantially if not entirely ventilated by this natural process, and the traditional energy-intensive, fan-driven ventilation system can be replaced.
In addition to regulating the temperature of the building with little or no use of motorized fans, natural ventilation also improves indoor-air quality by carrying undesirable and potentially toxic particles out of the building on a continuous current of fresh air.
A design test
In the design of the Baker Prairie Middle School in Canby, Ore., a scale model of the school was taken to the BetterBricks Integrated Design Lab, an effort of the Northwest Energy Efficiency Alliance and the Energy Studies in Buildings Lab at the University of Oregon.
At the daylighting lab, the design was tested to determine whether it would perform as ambitiously as desired. This analysis took into account many factors, including the proposed building’s orientation to sun and wind, the differences between winter and summer sun angles, and the landscape surrounding the building.
In addition to the model that was built for use at the daylighting lab, students from Canby High School’s building technology courses built a full-scale mock-up of a classroom on site.
This mock-up allowed the design team to experiment with the best place to put skylights, test natural convection systems, displacement ventilation systems, minimize and integrate electric lighting, conduct hour-by-hour sunlight simulations and test different types of window glazing.
The school, which was recently completed, will receive a LEED silver designation when the certification process is complete.
As a growing body of research confirms that sustainably designed schools reduce operational costs and increase student and teacher performance, communities also find that green design yields benefits that go beyond those measured in test scores and dollars.
By conserving natural resources, green schools foster an ethic of responsible land stewardship that builds a connection between communities and their natural environment a growing priority not just in conservation-minded places like Oregon but throughout the United States.
The improved physical health of building occupants supports an overall sense of wellness for teachers and students. When talking to occupants of sustainably designed schools, I have often heard students and staff alike remark that they feel thankful that their communities have provided them with a building that communicates respect and care, and supports the sense of pride and hope that motivates and inspires both children and adults.
Perhaps my own daughter said it best at the dedication ceremony for Baker Prairie Middle School: “Daddy, I wish I could go to a school just like this.”
Jerry Conduff has practiced at BOORA Architects for over 10 years, concentrating his design focus on primary and secondary education projects.