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Green product
Materials in use for sustainable design run the gamut from cotton insulation, to recycled asphalt paving, to photovoltaic arrays. Many products offer a green component that is at best incremental, offering performance or some other characteristic that is only slightly better than the conventional product. Use of these products by designers and contractors results in a positive effect that is now measurable.
In our experience, green product characteristics fall into six categories, and many products have benefits in multiple categories; however, a product that falls into three categories is not necessarily any more green than a product that falls into only one category.
1. Green process
2. Improved sustainability
3. Recycled content
4. Recyclable
5. Low toxicity
6. Biodegradable
Green Process: The product is manufactured with consideration for exposure of workers to chemicals, source of materials, energy-efficient production methods, use of recycled materials in packaging, reclaiming manufacturing waste, and prudent use of energy. Since many of these approaches actually save the manufacturer money, these principles are incorporated as manufacturing facilities are upgraded
Improved Sustainability: The product is renewable and makes good use of available resources. Sustainability considers the whole instead of specifics, emphasizing relationships rather than pieces in isolation. Sustainable design considers environmental and human health and well-being, in addition to the traditional criteria of function, cost, and aesthetics. While environmentalists have focused attention on the degradation of natural systems, advocates of sustainability generally believe in trading destructive behaviors for healthy ones and developing in ways that are beneficial ecologically and economically.
Sustainability can be illustrated by systems as well as individual products, such as those used to improve the energy performance of the building. For example, the current energy code of the Massachusetts State Building Code requires an air barrier in the exterior wall assembly and continuous insulation located outboard of the metal studs in a brick veneer-steel stud wall assembly. An air barrier can be established simply by taping the joints and perimeter of the exterior gypsum sheathing, but only by using a tape with a very low permeability and a high-performing permanent adhesive. Many architects have chosen to put a continuous air and vapor barrier membrane over the entire wall, again improving the long-term energy performance of the building and reducing the risk of premature failure of the exterior wall. Since the insulation is outside of the membrane, this allows the elimination of fibrous insulation in the metal stud cavity and the vapor barrier behind the interior drywall. Some prefer to limit fibrous insulation, and most acknowledge that an interior vapor barrier is frequently breached during installation or by wall outlets or other utility penetrations. The assembly improves the longevity of the exterior wall, decreases the risk of mold in the exterior wall, and improves the energy performance of the building.
Recycled Content: The product is fabricated with post-consumer materials or post-industrial by-products. Many products, ranging from steel, to finish materials, to carpet cushion, are manufactured with recycled content. For example, synthetic gypsum board is manufactured from gypsum deposited on the interior of smokestacks at coal-fired power plants during scrubbing. This gypsum is chemically the same as naturally occurring gypsum and does not have to be mined. However, considering the overall energy consumption and shipping costs of using synthetic gypsum board, it makes most sense to use it within 500 miles of its manufacturing location.
Other post-consumer materials include items such as plastic wood products fabricated using recycled plastic bottles. Products such as structural steel are always fabricated with both post-industrial (waste scrap) and post-consumer (salvaged steel) content.
Recyclable: The product can be reused or reprocessed after use and refabricated. We are most familiar with recyclable soda cans and bottles, but the same can apply to asphalt paving, masonry, metal framing, insulation, gypsum wallboard, acoustical ceiling panels, toilet compartments, and even carpet. Extruded polystyrene insulation manufacturers claim their product can be reused in roofing assemblies, since the material is not affected by moisture. Most major manufacturers of gypsum wallboard and acoustical ceiling panels provide facilities to recycle construction waste from their products.
Low Toxicity: The product is less toxic than comparable products used for the same purpose. Toxic fumes from site-mixed products, coatings, adhesives, and sealants containing such chemicals as formaldehyde and styrenes are a real threat to health, especially in remodeling projects where the building may be occupied while the work is being performed. Exposure to such products as carpet adhesives and high-performance paints has caused problems ranging from discomfort to long-term disability.
All products are now required to have Material Safety Data Sheets (MSDS) listing their components and potential hazards, but many architects have no training in interpreting them. Many hospitals and some manufacturing companies require MSDS submittals before they will allow a product at their construction site or manufacturing facility. Wood particleboard manufactured with resins that do not contain formaldehyde offers a less toxic environment for chemically-sensitive individuals and even for artwork stored in museums.
Biodegradable: The product returns to the earth naturally under exposure to the elements. The abandoned barn in the field eventually collapses and disappears. The subway car is dumped into the ocean as a marine habitat, and over time the steel corrodes. We expect our buildings to last a lifetime, but it is not necessary for products to last thousands of years.