Green Schools: Learning as We Go

Don’t expect to arrive at the other end of this article knowing how to design a green school (if you don’t know that already). Rather than providing an overview of school design, we seek with this article to describe some of the characteristics that distinguish schools from other buildings in terms of green design, review the benefits of green schools, touch on a few specific school design strategies, describe several green schools around the country, and finally, lead you to the most useful resources on how to design and build green schools.

Some Dramatic Numbers

Energy Consumption in Schools

According to

American School and University magazine, approximately 91,000 K–12 schools in the United States house 47 million students (2000-01 school year). Public school districts spent nearly $27 billion on construction in 2001 (42% on new construction, 42% on renovation, and 15% on additions), and expect to spend $108 billion more between 2002 and 2004.

Schools in the U.S. spend roughly $6 billion per year on energy. The breakdown of energy use in K–12 schools and higher-education facilities is shown in the pie chart on this page. Of the energy used on-site, space heating accounts for the most at 42%, followed by water heating (22%), and lighting (20%).

How Are Schools Different?

Schools are important if only because a lot of people spend a lot of time in these buildings. According to the U.S. Environmental Protection Agency (EPA), nearly 55 million people—one out of five people in this country—spend their days in school buildings—as students, teachers, administrators, and staff. Schools are different from most other buildings in a number of respects.

Schools have very high occupancy densities. Classrooms are among the most densely occupied interior spaces we create. (Assembly areas have higher densities, but these are typically occupied for only short periods of time.) Providing adequate fresh air for this concentration of people requires significant ventilation; indeed, ventilation typically drives the energy loads in schools, as we will discuss later.

Children are especially vulnerable to health hazards. Because human growth and development occurs at such a rapid pace during childhood, school-aged children are particularly vulnerable to contaminants. According to the Children’s Environmental Health Network (CEHN), on a weight-adjusted basis, children eat more food, drink more water, and breathe more air than adults do, and they have higher metabolic rates. Also, because their airways are smaller, they are more susceptible to air pollutants that cause asthma and other respiratory ailments. Through adolescence, rapid growth and development occurs in the nervous, respiratory, reproductive, immune, and other systems. CEHN argues that children, like other growing organisms, “can be more vulnerable to permanent and irreversible damage from toxicants than mature organisms.”

Productivity in schools is eminently measurable. Students’ productivity is being measured all the time—through testing. Thus, it should be very easy to quantify the benefits of high-performance, green schools. Significant progress has been made along these lines, particularly with a study of the effect of daylighting on student test scores in Capistrano, California.

Classrooms are specialized spaces that call for specialized design solutions. Certain characteristics of classrooms (particularly their small size and high occupancy) make integrated design solutions particularly attractive. (See discussion below on lighting and displacement ventilation.)

School funding mechanisms allow a longer view to be taken. Schools are typically funded by long-term bonds paid for by taxpayers who also fund the operation of those buildings. This can make life-cycle costing arguments and even features with long payback periods attractive to school boards. The fact that schools are paid for by taxpayers, however, also results in tightly watched construction budgets. A successful school design process will balance these often contradictory forces.

There is often naïveté among decision-makers in school construction. The design and construction of schools is often controlled by people who have never before been, and may never again be, involved in a nonresidential building project. Volunteer school boards and building committees climb a steep learning curve as they wend their way through the design and construction of a school. While this can be difficult (and frustrating for design professionals!), there is sometimes a refreshing open-mindedness not found with clients of most other building types.

Schools are places of learning. From an environmental standpoint, schools not only offer potential for direct reduction of environmental impact but, as places of learning, they can serve to educate their occupants about the environmental benefits of design features. Schools have tremendous potential for conveying a message about sustainability that will help to further its implementation throughout society.

Benefits of Green Schools

Improved student performance.A growing body of research demonstrates that green schools, especially those with natural daylighting, improve learning. In the daylighting study of the Capistrano, California School District referred to above, students in classrooms with the most daylighting progressed 20% faster in math and 26% faster in reading than students in classrooms with the least daylighting (see

EBN

Vol. 8, No. 9). This is by far the most comprehensive such study done to date, but there is clearly need for more research in this area. The federal government may also be getting involved as a result of efforts by Senator Hillary Rodham Clinton. Section 5414 of the “No Child Left Behind Act” of 2001 requires that the Secretary of Education study the health and learning consequences of unhealthy schools on students and staff. The act also allows for the Department of Education to award grants to state agencies for developing healthy, high-performance schools.

Reduced absenteeism.Green schools are designed and built to minimize indoor air quality problems—from mold and dust mites to volatile organic compound (VOC) emissions and tracked-in heavy metals. Healthier schools should result in lower absenteeism, among both students and teachers. After a 1997 renovation of the rundown inner-city Charles Young Elementary School in Washington, D.C., student attendance jumped from 89% to 93%. In some states, including California, a school’s operating budget is dependent on its

average daily attendance, so reducing absenteeism can increase operating budgets.

Greater teacher satisfaction.Comfortable, healthy, daylit classrooms will help to attract and retain quality teachers. There is a significant teacher shortage in some parts of the country, so competition for quality teachers can be significant. Green features may well provide the edge a school district needs to maintain top-quality education.

Lower operating costs.Energy-efficient, green schools cost less to operate. Because schools are built for the long haul and paid for by the same people who will pay to operate and maintain them, there are strong incentives to use life-cycle costing practices to identify measures that will lower operating costs. Many of today’s high-performance schools save 40% or more on energy costs, compared with conventional school buildings.

Reduced liability exposure.We live in a litigious society, and lawsuits by teachers or parents of students who may have been harmed by mold or other health hazards in schools are becoming more common. Green schools designed and built with careful attention to moisture control and using nonhazardous materials will be far less likely to result in lawsuits.

Key role in disaster planning.Like it or not, in the post-9/11 world, disaster planning is a significant part of building design. Schools often play a key role in a community’s emergency management—serving as storm shelters, central collection points during evacuations, and emergency housing during extended power outages. Highly energy-efficient schools with significant natural daylighting and renewable energy systems are easier to evacuate without power, and they will function far better during extended power outages than conventional schools. El Dorado Hills, California recently suffered a power outage lasting several hours, but classes at Oakridge High School were able to continue without interruption, due to the school’s extensive daylighting.

Schools require security features that can enhance health and energy efficiency. Schools require security features that can enhance health and energy efficiency.

A focus on security leads to a number of energy-efficient design choices. A tight building envelope, for example, not only enables the pressurization of a building, keeping biological or chemical hazards released outside the building from entering, but also helps control moisture, pests, and heat loss. Site design that includes a safety buffer zone between the building and vehicles also improves air quality immediately surrounding the building and allows optimal use of passive and active solar design. Exterior lights with occupancy sensors provide better security than those left on through the night; the sensors also reduce light pollution and save energy.

Lower environmental impacts.Green schools are designed and built to minimize environmental impacts. They use energy and water frugally; they are durable and built of materials with low maintenance requirements. Green schools are placed responsibly on their sites in a manner that protects wetlands and wildlife habitat, and landscapes are designed to maximize infiltration of stormwater to replenish aquifers. Waste is minimized during construction, and provisions are made for recycling wastes within the building. More and more green schools are relying, at least to an extent, on renewable energy sources.

Environmental education.Coming to grips, over the coming decades, with the significant problems facing our environment will require action on many different fronts. Schools have an important role to play in this effort. As places of learning, our schools not only should be green in their construction and operation but should themselves be teaching tools. Many of the features incorporated into green schools—from renewable energy and daylighting systems to stormwater infiltration practices—are ideal hands-on laboratories.

Promising Technologies

As noted previously, schools have a number of unique characteristics that create both challenges and opportunities when it comes to school design and construction. We address two of these opportunities here, pointing out in both cases the need for research and development work.

Integrated lighting controls

While daylighting can be very beneficial in classrooms, good lighting control is a challenge. Glare must be controlled, there usually has to be a way to darken classrooms, and for energy savings to be realized with daylighting there has to be a trouble-free mechanism for turning off electric lights when they aren’t needed.

Simple, trouble-free, automated daylight controls with dimming ballasts for fluorescent light fixtures are the best solution for this, but they are expensive and have proven problematic. “Most daylighting controls [in schools] simply don’t work,” according to Charles Eley, Ph.D, P.E., of Eley Associates in San Francisco. (Eley’s firm manages the Collaborative for High Performance Schools [CHPS] in California.)

Dave Nelson, P.E., of Clanton & Associates, Inc., a lighting design firm in Boulder, Colorado, agrees with Eley on the challenges of effectively controlling daylit classroom spaces. Clanton Associates has moved away from complex automated controls for daylit spaces. They almost never use fully automated dimming controls anymore. Nelson recommends a multipronged approach for classroom daylighting. First, he suggests architectural features for control of glare—orientation of fenestration, overhangs to block direct sunlight, and so forth. Second, he recommends interior shades or blinds to offer variable light levels and permit classroom darkening for audiovisual presentations. While automated, three-part roller shades are great, these are usually too expensive for schools. A less expensive option is a manually operated, two-component shade system with a perforated shade that allows about 10% transmittance and a full-blackout shade. Third, he likes simple manual-on, auto-off electric lighting controls, with separately controlled lights on the window-side of a classroom. With this approach, occupancy sensors are used to turn lights off when people leave the room. Because most classrooms have two rows of fixtures, he recommends controlling these separately, with the switch for the outer row (along the windows) located near that row of fixtures rather than by the door. “You make them work a little to turn on the outboard row,” he suggests.

While these approaches for lighting control make the most sense today, we should be able to develop reliable, affordable daylight-activated dimming controls. “A photocell is not that complicated,” says Eley. He would like to see some sort of “Golden Carrot” program for manufacturers to develop such products.

Packaged displacement ventilation systems

The small size of classrooms, typically 30’ x 30’ (9 x 9 m) and their approximately square configuration make displacement air supply/ventilation both very effective and (in theory) relatively easy. With displacement ventilation, conditioned air enters low in the space and rises slowly to the ceiling, where it is captured and exhausted. Because the air flows upward, little mixing occurs and pollutants are effectively eliminated. Less air needs to be moved (allowing for smaller fans), and conditioned air doesn’t have to be chilled as much, because the conditioned air isn’t mixed with classroom air. Also, the heat generated by lights remains above the occupied zone, so energy savings can be realized. In large commercial office buildings,

access floors are generally required to achieve low-velocity, uniform displacement ventilation (see

EBN

Vol. 7, No. 1), but in classrooms, displacement ventilation can be achieved using a few strategically positioned, low, wall-mounted diffusers. “In schools you don’t really need access floors,” says Eley.

The problem today, according to Eley, is that displacement air-supply systems have to be custom-engineered for every school. Most off-the-shelf systems used in schools don’t have the capability for preconditioning the air, according to Eley. “Most schools are catalog-engineered,” he says. “What we need … are some high-performance options in the catalog.”

The H. L. Turner Group of Concord, New Hampshire has been working on just such an approach, which they refer to as the Advantage Classroom™. According to company president Harold Turner, P.E., they began working on the Advantage Classroom in 1994 in an effort to address various historical problem areas of classrooms—especially indoor air quality, lighting, and acoustics. The Advantage Classroom uses an integrated design approach with several key features: 1) a tight, energy-efficient building envelope; 2) high ceilings that provide both superior daylighting and stratification of the classroom air; and 3) delivery of preconditioned, 100% fresh air from side-wall diffusers near the floor level. The supply air is cooled and dehumidified using a heat-pipe enthalpy energy-recovery system rather than enthalpy wheels, which Turner has found to be problematic.

This approach was first used in the Boscawen Elementary School near Concord, New Hampshire, completed in 1996 at a total construction cost of just $65/ft² ($700/m²). The classrooms achieve superb air quality with an overall ventilation rate of only 1.5 air changes per hour—less than half that required by a conventional ceiling-diffuser design. In developing the Advantage Classroom, H. L. Turner worked with manufacturers of mechanical components, in some cases convincing them to produce specialized components. They have used this approach in about ten schools in northern New England.

So why doesn’t everyone use this type of system? For starters, not many people are aware of this approach. H. L. Turner hopes to change that by teaching other design and engineering firms how to implement the Advantage Classroom. Though the company has been too busy in recent years to promote this design assistance and education service, they are now ready to do that. A quasi-licensing arrangement, mostly to ensure that the system gets implemented properly, has been set up, according to Harold Turner.

William Turner, P.E., who manages H. L. Turner’s Maine office, notes that integration is key with this approach. “The biggest challenge in doing side-wall displacement in schools,” he says, “is coordinating between the architect and mechanical engineer.” As a full-service architecture/engineering firm, The H. L. Turner Group effectively coordinates design and engineering tasks; when those functions are separate, integration gets harder.

Final Thoughts

In many respects, schools should be our highest priority of any building type for greening. The importance of our children’s health, the significance of school buildings in a community (both financial and cultural), and the potential for school buildings to serve as tools to teach sustainability all argue for devoting effort toward making these buildings green. Such efforts can involve our professional activities—as designers, product manufacturers, or contractors—but many more of us can contribute as members of the communities in which we live. Even if school design is not part of your professional work, get involved with the next school building committee, or at least convey to your local school board the importance of sustainability.

– Alex Wilson

For more information:

Children’s Environmental Health Network

110 Maryland Avenue NE, Suite 511

Washington, DC 20002

202/543-4033

www.cehn.org

Healthy Schools Network, Inc.

773 Madison Avenue

Albany, NY 12208

518/462-0632

www.healthyschools.org

The H. L. Turner Group Inc.

27 Locke Road

Concord, NH 03301

603/228-1122

www.hlturner.com

(See also organizations listed in Resources table, Sidebar: Resources for School Design.)