Page 200 - Design for Environment A Guide to Sustainable Product Development

Analysis Methods for Design Decisions 179

• Conventional LCA does not account for ecosystem goods
and services and the impacts of renewable resource use
However, with appropriate definition of system boundaries, LCA
can be useful for identifying the environmental advantages or draw-
backs of various design options, thus supporting product develop-
ment decisions [14]. Caution should be exercised in using the results
of such analyses for external marketing and communication, such as
comparative product claims. A good illustration of LCA application
to consumer products is provided by the Kimberly-Clark example
presented in Chapter 16. Another example of an industry-wide LCA
for automobiles is shown in Chapter 12, Figure 12.2.

Impact Assessment
Within the life-cycle assessment framework described above, the third
and most challenging step is assessment of the impacts associated
with resource use and environmental emissions during each life-cycle
stage—acquisition, manufacture, transport, use, and disposal of prod-
ucts. These impacts may include environmental, health or safety
impacts upon humans and ecosystems, as well as economic impacts
such as land use restriction and resource depletion. Moreover, im -
pacts may be local, regional or global in nature. The assessment of
impacts is problematic because we have a relatively poor understand-
ing of the complex physical and chemical phenomena that determine
the fate and effects of substances released to the environment. Despite
a great deal of continuing scientific research, our knowledge remains
fragmentary and largely theoretical. In some cases, such as green-
house gas emissions or energy consumption, the impacts are cum -
ulative and broadly distributed, but in other cases, such as mercury
emissions or water resource consumption, the impacts are highly
localized and dependent upon specific environmental conditions.
There is a vast literature on environmental impact assessment (EIA),
mainly oriented toward the evaluation of proposed policies or projects
that may affect the environment. In the United States and many other
countries, EIA is a legal requirement prior to the initiation of major
construction or development projects. However, most of the methods
used in this field are not appropriate for product development pur-
poses because they are detailed and site-specific; whereas LCA is
applied at a broader system level. Instead, life-cycle impact analysis
uses simplified models that provide relative measures of impact with-
in broad categories. These categories reflect “midpoint” indicators of
potential impact rather than final endpoints. For example, the TRACI
tool developed by U.S. EPA uses the following categories [15]:
• Stratospheric ozone depletion due to airborne emissions of
substances, such as chlorofluorocarbons (CFCs) and halons.