Green Building Programs - Influencing Positive Change, But Fundamental Flaws Inhibit Effectiveness

摘要

Green buildings programs have been developed in North America over the past 10-15 years with an objective of shifting the built environment toward a more sustainable mode. Such programs are important - certainly in concept -in focusing building designers and construction firms on more efficient use of energy and water, improvement of indoor air quality and occupant safety, development of more liveable and environmentally sustainable communities, and reduction of environmental impacts in the construction and operation of buildings. Because green buildings programs are important, it is therefore important that these programs be free of biases and political pressures and that they actually promote improved environmental performance. Accordingly it is critical that guidelines and requirements of these programs be rigorous, comprehensive, and science-based. However, within the leading green building program operating in North America - the LEED (Leadership in. Energy and Environmental Design) program - designations of green materials are made without the benefit of systematic, comprehensive analysis, with criteria largely based on intuition and focused on single attributes. There is no consideration of the quantity of energy consumed in manufacturing and transporting products or product assemblies, despite the fact that such energy is often equivalent to many years of energy consumption associated with a structure, nor is there any consideration of emissions linked to production and use of construction materials. A fundamental problem is that there is no requirement for consideration of life cycle inventory data using common criteria as part of the materials rating system; what this means is that LEED has no capacity for rigorous assessment of environmental impact. Moreover, in LEED and all other current green building programs, despite the reality that production of all materials results in significant environmental impacts, only wood is held to standards linked to extraction. The result is designation of "environmentally preferable materials" using single attributes that don't often stand the test of rigorous assessment, that fail to require systematic consideration of environmental impacts through the product life of all materials, and that ignore fundamental aspects of sustainability. It is time to require rigor in the assessment and designation of environmentally preferable building products. Specifically, LEED and similar green building programs need to shift away from intuition-based prescriptive measures of environmental performance, and toward the use of LCA in designation of environmentally preferable materials and products. In addition, if certification programs are to be required as part of materials assessment, then proactive action should be taken to ensure that the same questions are asked of, and the same requirements imposed on, manufacturers and suppliers of the full array of building materials.