Page 133 - Design for Environment A Guide to Sustainable Product Development

112 Cha pte r Se v e n

certain life-cycle stages from consideration because they are not rele-
vant to business decision making (see Chapter 10). Therefore, the
intended scope and rationale for metrics should always be clarified.
For example, rather than speaking of “energy use reduction” we
should specify “reduction in energy use during manufacturing and
distribution” or “reduction in power consumption during product
end use”.
Another important consideration in the selection of metrics is
recognizing the interactions among environmental and other prod-
uct and process metrics. For DFE to be truly integrated with product
development, engineers must understand the synergies and trade-
offs among environmental performance attributes and other design
attributes. Specifically, product development teams should analyze
the pairwise interactions between environmental metrics and those
that relate to cost, performance, and customer satisfaction. In the
“house of quality” approach discussed in Chapter 5, this is equiva-
lent to examining the “roof” of the house.
Table 7.3 illustrates interactions that might be identified for a hypo-
thetical consumer product such as a cleaning agent. Again, each row
represents a class of primary environmental metrics; the arrows repre-
sent the direction of desired improvement (up or down). In this case,
interactions are shown as either favorable (star) or potentially unfavor-
able (question mark). Note that it is also possible to indicate the degree
or strength of interaction in qualitative terms. When applied to specific
products, this type of interaction matrix reveals some important
insights. For example, one can readily see the synergies between life-

Performance Cost Safety Convenience Aesthetics
Energy usage

Water usage

Source
volume ? ?
Recycling &
reuse ?
Waste &
emissions
Recycled ? ?
materials

TABLE 7.3 Example of Interactions among Environmental Quality and Other
Customer Benefits for a Consumer Product