Design for Disassembly in the Built Environment

Design for disassembly (DfD) is a growing topic within manufacturing industries as greater attention is devoted to the management of the end-of-life of products. This need is driven by the increasing disposal problems of large amounts of consumer goods, and the resultant pollutant impacts and the loss of materials resources and energy that is embodied in these products. In Europe, in particular, constraints on the production of waste and pollution have resulted in an emphasis on ?extended producer responsibility? legislation such as the Directive 2000/53/EC of the European Parliament on end-of-life vehicles and Germany's End-of-Life Vehicle Act of 2002.Extended producer responsibility (EPR) is defined as ??making the manufacturer of the product responsible for the entire life-cycle of the product and especially for the take-back, recycling and final disposal of the product? (Toffel, 2002). Simply put this requires that those who create a product are responsible for designing its entire life-cycle, including its ultimate disposition, with reuse and recycling, to achieve economic profitability at minimum risk. As buildings are manufactured artifacts typically comprised of a combination of pre-assembled components and on-site assembly of materials and components, design for disassembly can be applied to the built environment similarly to other assembled artifacts. Although not typically considered a ?product?, buildings are nonetheless composed of materials, components, and connections, and are created through the collaboration of designers, engineers, trade-persons, and the manufacturers of the materials and components that are assembled to make the building. Buildings of course are much longer-lived than other artifacts, larger, more complex and subject to a myriad of forces, such as gravity, climate, and use. Because of their importance in society and tremendous impact on resource utilization globally, any attempt to consider sustainability in the use of building-related resources must consider the management of all resource flows in the full life-cycle of buildings from extraction, to manufacturing, to design, to construction, to operation, to renovation, to eventual end-of-life. This management is a fundamental goal of design for disassembly (DfD) in the built environment. There are many practical reasons for incorporating DfD in the built environment. The US Geological Survey has estimated that 60% of all materials flow (excluding food and fuel) in the US economy is consumed by the construction industry (Wagner, 2002). The US EPA has estimated that 92% of all construction-

related waste produced annually in the US is the result of renovations and demolitions, with only 8% produced from new construction, and that this waste is upwards of 30% of all waste produced in the US (Franklin Associates, 1998). Nelson has estimated that the total built space in this country will need to grow from 296 billion square feet in 2000, to 427 billion square feet in 2030. Of this growth, 82 billion square feet of building will be from replacement of existing building space and 131 billion will be from new construction totaling 213 billion square feet of new built space. This means that 27% of existing buildings in the year2000 will be replaced from 2000 to 2030 and that over 50% of buildings in the year 2030 will have been built since 2000 (Nelson, 2004). This huge mass of buildings that are to be replaced and newly constructed can either be large sources of waste in the next 25 years and afterwards, respectively, or the materials from existing buildings can be recovered for reuse and recycling, and these new buildings canbe designed to recover their respective materials in the next generation of replacements. DfD is intended to address this trend by explicitly creating buildings to reduce new materials consumption and waste in their construction, renovation and demolition, to increase building lives in situ, and to create buildings that are stocks of future building materials.This enabling of materials conservation and buildings that facilitate the recovery of their components for the next iteration is intended to provide both economic and environmental benefits for builders,owners and occupants, and communities where these buildings reside.