Page 199 - Design for Environment A Guide to Sustainable Product Development

178 Cha pte r Ni ne

Life-Cycle Assessment
Life-cycle assessment (LCA) methods are used to estimate the net
energy or material flows associated with a product life cycle as well
as the associated environmental impacts [13]. The Society for Environ-
mental Chemistry and Toxicology was the first organization to develop
a standard methodology for LCA in the early 1990s, involving the
following steps:

1. Goal and Scope. Define the product, process, or activity to be
assessed and the goal, scope, and system boundaries of the
assessment.
2. Life-Cycle Inventory. Develop a system-wide inventory of
the environmental burdens by identifying and quantifying
energy and materials used and wastes released to the envi-
ronment at each stage of the life cycle.
3. Life-Cycle Impacts. Assess the impacts of those energy and
materials uses and releases upon the environment and/or
human health.
4. Interpretation. Evaluate the results and implement opportu-
nities for improvement.
The original LCA methodology has been updated and stan-
dardized through guidelines developed by the International Orga-
nization for Standardization (ISO 14040:2006 and ISO 14044:2006).
These guidelines ensure that all assumptions are transparent, that
the system boundaries and functional unit of analysis (i.e., product
or service value delivered) are clearly defined, and that data quality,
un certainty, and gaps are clearly stated.

Traditional LCA studies have been based on “bottom-up” analy-
sis of specific industrial processes along the supply chain, which can
be burdensome. Although many companies have adopted LCA in -
ventory methods, the use of impact analysis is more controversial.
There are a number of limitations to the LCA methodology:
• Rigorous application of LCA requires specialized expertise
and training, and can involve considerable time and expense.
• Process-level data are difficult to obtain and may have large
uncertainties, especially with new technologies that have not
been in widespread use.
• Drawing system boundaries is necessary but may omit impor-
tant stages in the upstream supply chain or downstream prod-
uct use chain.
• Inventory assessment alone is inadequate for meaningful
comparison, yet impact assessment is fraught with scientific
difficulties.