Introduction of Green Building Materials
Materials are the stuff of economic life in our industrial world. They include the resource inputs and the product outputs of industrial production. How we handle them is a major determinant of real economic efficiency, and also has a major impact on our health and the health of the natural environment The built-environment is also a strategic realm of social, economic and environmental change. Various writers have stated that spatial redesign of the landscape and built-environment may be the single most effective means of achieving new levels of efficiency and sustainability (Lyle, 1994; Mollison, 1983; Alexander, 1977; Van der Ryn & Cowan, 1996). Building materials are also quite important. They have been estimated that building materials make up forty percent of material through-put of entire economy (Milani, 2001). In the book “Green Building: Project Planning and Cost Estimating”, Keenan and Georges (2002) identified some key characteristics of green building materials. As regards green building materials, they should be healthy for the internal environment, healthy for the natural environment, minimize building energy use, have low embodied energy, be reusable, recyclable and/or biodegradable, and be locally obtained. Embodied energy is a concept that takes into account several factors to determine the energy needed to produce a product and can be used as a comparison between different materials. There is some controversy surrounding embodied energy as there is no internationally agreed method for calculating this value and many times it is not known what has been accounted for (Woolley and Kimmins, 2005). For example, cement has an embodied energy of 7.8 MJ/kg, while virgin steel is 32.0, and recycled steel is 10.1 MJ/kg (Keenan and Georges, 2002). In these values however, consideration is not given to transportation, durability, reuse and recycling. These factors could significantly alter the original values. Building materials are also the stuff of our personal environments. They are all around us, and literally part of the air we breathe. They can damage the biosphere: VOCs from paints alone are responsible for perhaps 9 percent of the damage to the ozone layer. They can also damage us: the US Environmental Protection Agency (EPA), for example, estimates that indoor pollution—caused by materials like paints, plastics and particleboards—is responsible for more than 11,000 deaths each year from cancer, kidney failure, and respiratory collapse (Ligon, 2001). The fact that buildings are all around us means not only that they immediately impact us, but that we can potentially affect them. The building industry is a decentralized one that exists in virtually every community. Not surprisingly, the built-environment is a major venue for ecological and community development alternatives, with materials being an increasing focus of concern over the past decade. LEED CERTIFICATION REQUIREMENTS
In the LEED green building rating system for new developments, there are two sections which pertain to building materials. The first is the section on Materials and Resources. This section consists of one prerequisite and eight credits. The eight credits focus on reuse and management of construction and demolition waste; using refurbished or reused materials and materials with a recycled content; using regional and rapidly renewing materials; and lastly if new wood must be used, using products certified accordance with the Forest Stewardship Councils principles and criteria The second section which pertains to building materials is Indoor Environmental Quality. The important credit is number four: Low Emitting Materials. For this credit, the Volatile Organic Carbon (VOC) content of adhesives and sealants must be less than the VOC content limits of the State of California South Coast Air Quality Management District’s (SCAQMD) rule number 1168 from October 2003. For paints, the...
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