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In general, a product with a longer life cycle that serves the same purpose as that of another one has a minor environmental impact. If a product lasts for a lesser amount of time, not only can it generate more waste, but most of all, also has a major environmental impact when substituted with a new product. This product, in turn, will consume new resources and produce new emissions at the moment of its production, distribution and application.
The life cycle of a building entails its design, construction, occupancy, maintenance, repair, renovation, alteration (e.g., change in purpose, space, internal arrangement), restoration and deconstruction. Occupancy and maintenance generally account for most of the environmental impacts over the life cycle of the building due to the relatively high, non-renewable energy demands of most buildings. Repair, renovation and restoration vary in degrees of impact, depending on the durability of the building components and the flexibility/adaptability of the building system. As building technology gains in sophistication in the integration of systems, it is important to consider the durability of constituent elements.
In components such as walls and roofs that are comprised of multiple layered and/or overlapping materials, the least durable material limits the resultant ability to service it. As to the efficacy of building services, the accessibility for repair and replacement of these materials is critical. If these are inaccessible or concealed within the fabric of the building, their premature deterioration and defects, or even simple obsolescence, will imply the costly and disruptive deconstruction of well-performing fixtures and finishes. In all cases, the value and importance of intelligent design is reinforced by its ability to optimise the life cycle of the building in order to offset these possible negative influences.
Most building material manufacturers offer excellent guidance on durability considerations in the selection and application of materials. Aside from instances of misrepresentation or sub-standard quality of the material, it is almost always the fault of the designer for choosing defective materials, by having failed to consider its use and support of the environment, its interaction with other materials and components, and/or its dependence on flawless workmanship for acceptable performance. The selection of materials is relatively easier to undertake than the detailed design of durable components or systems. |
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