Different assessment methods evaluate materials by means of indicators, which facilitates a comparison of different materials with a view to their environmental performance. In most cases indicators will be calculated from life cycle analysis data (LCA), which can be used as a basis for the assessment of the environmental impact of materials. Of course, each of the methods used yields results only within its own bounds. Therefore, knowing these limits and the potential environmental impact not detected by a given method is essential for application in practice.
The use of ecotoxic substances should be avoided where possible during the whole life cycle for environmental reasons as well as for reasons of health. Toxic substances may have serious effects even if used in small quantities (dioxine, PCB, PVC, ... and should therefore be avoided, in particular, when they are or could be contained in external parts or components. It is therefore important to avoid such substances during the whole life cycle of a product.
The use of renewable raw materials, as a rule, not only provides for adequate disposal but also takes into account the issue of resources (renewable resources as a crucial criterion for sustainability). Renewable raw materials are not of fossil origin but are made, in most cases, from plants (wood, corn, rape, hemp...); for some applications they show very similar, often even better characteristics than other materials. The environmental benefit (conservation of resources and easier disposal) constitutes an argument for the use of renewables.
Closed cycles form a constituent element of ECODESIGN. This also means that material cycles have to be closed. One of the prerequisites in this context is to use only materials that are really recyclable and that ensure, at the same time, that its characteristics are also present in the secondary material to a sufficient degree (if necessary by adding new material).
Materials that are as such recyclable, too, can become a problem with a view to closed cycles if they have to be glued together with or otherwise inseparably bonded to other materials for reasons of strength or stiffness. In this case, recyclability would be impaired or even impossible, which would require disposal at the end of life of the product.
Apart from the materials characteristics themselves the conditions for the production of comparable raw materials may vary greatly. Replacing raw materials of known problematic origin by similar or equivalent raw materials may considerably reduce the total consumption of resources. The overall environmental balance will not be impaired as compared to production on other sites.
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