Design: selecting materials for eco-design

For selection of materials in environmentally responsible design we must first
ask: which phase of the life cycle of the product under consideration makes the
largest impact on the environment? The answer guides the effective use of the
data in the way shown in Figure 20.12.
The material production phase
If material production consumes more energy than the other phases of life, it
becomes the first target. Drink containers provide an example: they consume
materials and energy during material extraction and container production, but,
apart from transport and possible refrigeration, not thereafter. Here, selecting
materials with low embodied energy and using less of them are the ways forward.
Figure 20.7 made the point that large civil structures—buildings, bridges,
roads—are material intensive. For these the embodied energy of the materials
is the largest commitment. For this reason architects and civil engineers concern
themselves with embodied energy as well as the thermal efficiency of their
structures.
The product manufacture phase
The energy required to shape a material is usually much less than that to create
it in the first place. Certainly it is important to save energy in production. But
higher priority often attaches to the local impact of emissions and toxic waste
during manufacture, and this depends crucially on local circumstances. Clean
manufacture is the answer here.

Materials
Engineering, Science,Processing and Design
Michael Ashby, Hugh Shercliff and David Cebon
University of Cambridge,
UK
AMSTERDAM • BOSTON • HEIDELBERG • LONDON • NEW YORK • OXFORD
PARIS • SAN DIEGO • SAN FRANCISCO • SINGAPORE • SYDNEY • TOKYO
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