Sustainable Building Technical Manual - Etn-presco.net

❑ Resource-efficient options– Consider lightweight concrete blocks and bricks made with expanded aggregatessuch as pumice to reduce weight and add insulating value.– Other options are brick and block products with waste and recycled contents, suchas sewage sludge and ash from incinerators and coal-burning plants. However, suchash should be tested for pollutants that could cause unacceptable health or environmentalexposures. Hollow blocks are available with waste wood fiber and other recycledcontent. Native stone or lightweight cultured stone made from cement andrecycled aggregates are appropriate for some uses.– Glass block is available with recycled glass content.❑ Health and pollution issues– Overall, masonry products produce minimal air pollution.– If sealers are needed to repel water, a low-volatility, water-dispersed product is saferthan a solvent-based variety.Division 5: MetalsSteel is the most common metal used in building products. It is highly recyclable, and itsscrap has value. Aluminum, the second most common metal, is probably the most recyclablematerial in buildings. Stainless steel and brass products are alloyed metals that arerecyclable if carefully separated by type. Copper is also a highly valued recyclable.Metal plating is common in building products, especially in architectural metals, doorhardware, and office systems and furniture. Chromium, cadmium, brass, and nickel platingis often carried out by electroplating plants, sometimes resulting in high levels of pollution.Emissions such as hexavalent chromium and cadmium and acid wastes areenvironmentally toxic. Plastic polymer coatings and “powder coatings” are alternatives;however, the use of plated metal versus plastic polymer coatings should only be evaluatedby comparable life-cycle assessments, which can be done by using ASTM life-cycleassessment standards.❑ Resource-efficient options– Steel with verified recycled content of 30 percent or greater is available from sourcesin the United States.– Aluminum from U.S. sources may have 20 percent or more of verified recycled content,which usually is derived from recycled consumer-product containers.– Salvaged steel and aluminum beam and bar sections are also widely available fromscrap dealers. These may be appropriate for some nonstructural uses.– Architectural metalwork such as antique iron and brass, lighting fixtures, and doorhardware are also readily available from building salvagers.❑ Health and pollution issues– Indoor air pollution is a minimal problem with metal products. The only exceptionsare products that may require polishing, cleaning, or repainting in place. (See“Division 9, Finishes,” below.)Division 6: Wood and PlasticWoods used in construction and interior finishing are primarily domestic species. Woodsused in furniture, doors, and specialty millwork are often imported tropical varieties.Appropriate forest management is vital to more sustainable wood sources in many cases.Processed woods and wood substitutes are an alternative and are discussed further in“Division 12, Furnishings,” below.Most plastics are made from “nonrenewable” petroleum or natural gas feedstocks. Theirproduction may involve use of toxic and potentially hazardous substances. Plastics aresometimes used in building systems as claddings and panels, but most often in interiorfinishes. These uses are discussed below in “Division 9, Finishes.”