Page 50 - Materials Chemistry, Second Edition

3.1 Life cycle assessment methodology 45
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Climate change Terrestrial Human toxicity Particulate matter
acidification formation
Production Distribution Installation Use Dismantling End of life
FIG. 3.3 Example of LCIA results.

– Normalization. The aim of normalization is to clarify the relative importance of the
indicator results. Values are divided with reference to a standard value.
– Weighting. The categories results are assigned numerical factors in accordance with their
importance, then multiplied by these factors and finally aggregated in a single
impact score.
Classification and characterization are mandatory elements, whereas normalization and
weighting are discretionary (ISO, 2006a).

3.1.4 Life cycle interpretation
In this phase, the results of the LCI and LCIA are considered together with reference to the
objective of the study. The interpretation is comprised of several elements (ISO, 2006a,b):

– Identification of the significant issues based on the results of the LCI and LCIA phases.
The objective of this step is to analyze the results from the LCI or LCIA phases in order
to help determining the significant issues,inaccordancewiththe goal andscope
definition.
– An evaluation that considers completeness, sensitivity, and consistency checks. During this
evaluation, the following techniques should be used: completeness check, sensitivity
check, consistency check. The results of uncertainty analysis and data quality analysis
should supplement these checks. The completeness check is performed to control that all
the needed data and information are available and complete; the sensitivity check is
performed to evaluate the reliability of the results; and the consistency check is conducted
to determine whether assumptions, methods, and data are coherent with the goal and
scope defined.
– Conclusions, limitations and recommendations.