Green Giants

Nov. 1, 2001
Constructing "green" buildings on campus doesn't have to break the budget.

The design and construction of sustainable school buildings is about creating buildings that are friendly to the environment and building occupants.

This involves paying attention to fundamentals such as basic building design, site configuration and energy-efficient equipment.

Sustainability also involves the selection of materials and systems that have minimum negative impact on the environment as they are manufactured, are easily recyclable and are safe for the occupants of the building.

While some sustainable materials do come at a cost premium, some also offer a longer useful life or reduced maintenance requirements. In many cases, it is the way a material is incorporated into the design that determines whether it deserves designation as sustainable.

The most efficient way to create a sustainable facility is to get early input from a planning team that includes sustainable design specialists and materials specialists, along with the architect, contractor, building administrator, and staff and students.

The bottom line

The less energy a building uses, the less fuel is required; that translates into less drilling and mining, less energy consumed in its transport, and less fossil-fuel residue released into the air when it is burned. Of course, it also means a smaller energy bill for the school.

By designing a building appropriate to the local climate and configuring it properly on a site to take advantage of natural light and solar heat, administrators can go a long way toward making a building “green.”

Equipping that building with advanced heating, ventilation and air-conditioning systems can bring additional efficiencies. Modern technologies such as heat-recovery systems, which take advantage of internal air that has already been preheated or precooled, reduce fuel consumption even further. In energy-hungry areas such as science laboratories, a variable-volume exhaust-hood system can substantially limit the amount of already heated or cooled air that is vented wastefully to the outside.

The cost/benefit ratio for advanced technologies such as these was not favorable until recently. With energy costs up sharply and rolling blackouts a reality, these technologies are both green and cost-effective. Impending energy-efficiency regulations and tax incentives make them even more appealing.

Making maximum use of natural light in schools is an important consideration. Obviously, the more natural light is used, the less electric power is consumed. But recent studies indicate that this is not the only benefit of natural light; it also positively affects learning, as measured by a rise in test scores where natural light is maximized.

What makes a material sustainable?

The answer gets rather convoluted. It generally is not correct to simply say that bricks are green and steel is not. How the material is produced must be taken into consideration, as well as how it is used.

Among the factors to be considered: the type of resources that must be extracted and the effect on the environment, the existence of negative by-products that might be created in production, packaging and transportation needs, durability and recyclability.

Complicating the equation is the way the material is applied to the project, what maintenance may be involved and what life cycle can be expected.

The example of carpeting may be useful to understand how flexible greenness can be. Ten years ago, nylon carpet with its relatively high environmental cost to manufacture was considered un-green. Without proper maintenance it could become a sink for such unwelcome things as pesticides that could be tracked in from surrounding lawns, and that it was dumped in the landfill at the end of its service life, nylon carpet sank near the bottom of the environmental pecking order. Today, though, nylon carpeting can be manufactured with a substantial recycled content, and be recycled yet again after use.

For example, carpet tiles are considered more sustainable because individual tiles can be replaced instead of replacing an entire area. Some manufacturers are manufacturing carpet backing without polyvinyl chloride (PVC). Many consultants suggest avoiding PVC because of negative impacts associated with the manufacturing and incineration of such products.

Other materials are less ambiguous in their sustainable authenticity. Wood from a certified forest leaves little room for argument about its positive environmental impact.

Some ceiling tiles are manufactured from perlite, a byproduct of volcanic stone. While it is more costly than conventional cellulosic ceiling tiles, it pays dividends in terms of fireproof quality and lengthened service life. Being entirely inorganic, it will not contribute to the growth of mold or bacteria. This helps to create a healthier building.

Minimizing toxins

While there is flexibility in many definitions of sustainable materials, one sound principle is to keep toxins to a minimum in any school structure. It is not always as easy as it sounds. Particleboard, for example, is a widely used material for building shelves and cabinets. Unfortunately, many formulations of particleboard contain formaldehyde, designated as a suspected carcinogen by the EPA. Now there are alternative bio-based products made from wheat, straw or urban wood waste, using a chemical called MDI. While MDI is not wholly benign, it can be catalyzed to prevent what is referred to as off-gassing.

Volatile organic compounds (VOCs), which consist of carbon atoms that vaporize when exposed to oxygen, should be minimized wherever possible. VOCs occur in paints, adhesives, sealants and waxes. New paints have been developed that contain little or no VOCs, but they may not be durable enough for a school. In order to use paints that will not require excessive maintenance in this application, schools should make sure the building is aired out thoroughly before occupancy.

With such materials as floor wax, sometimes simple common sense is enough to keep VOCs to an acceptable level. Either use a wax low in VOCs or wax the floor on Friday evening instead of during the school week, allowing more time for flushing out. Use the same rule for many building cleaning products and for inside and outside applications of pesticides.

An air-quality monitoring system that warns when levels of undesirable toxins have reached unsafe levels adds a welcome safeguard.

National standards

Sustainable design standards are at present a patchwork of guidelines that vary state to state and city to city. There are, however, signs of a growing consensus that such standards are desirable and inevitable in the long run. LEED, Leadership in Energy and Environmental Design, is emerging as the nationally recognized standard for what constitutes a green building.

Even among commercial building owners, a national movement is beginning to look at materials and their compliance with a budding green building rating system. These standards can only help administrators construct “green” buildings on campus that don't break the budget.

Wright is director, Sustainable Design Services and Maine is sustainable design research director with HDR Architecture, Inc., Omaha, Neb.

In the schoolyard

Not all hazards in education facilities occur in the indoor environment. For decades, wood play equipment has been manufactured with CCA (chromated copper arsenate), a lumber preservative that contains 22 percent arsenic. Recent evidence suggests that the arsenic, which is classified by the EPA as a carcinogen, will tend to leach out of the wood and end up in the soil beneath the equipment.

Moreover, even though the EPA recommends that people who work with CCA lumber use gloves and masks, it makes no such recommendation for children who play on the material and risk ingestion of arsenic by hand-to-mouth contact. In fact, a child might easily ingest from five to 10 times more arsenic by playing on CCA-treated wood than from ordinary food and water consumption.

The fact that there are economically viable alternatives to CCA lumber, such as non-toxic ACQ, should provide administrators and facility managers with the opportunity to eliminate a dangerous material from the schoolyard.

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