Page 89 - Materials Chemistry, Second Edition

LIFE CYCLE IMPACT ASSESSMENT 71

LIFE CYCLE IMPACT ASSESSMENT

Mandatory elements
C Selection of impact categories, category indicators and characterization models

Assignment of LCI results (classification)

[ Calculation of category indicator results (characterization)

Category indicator results, LCIA results (LCIA profile)

^^>L
Optional elements
Calculation of the magnitude of category indicator results
relative to reference information (normalization)
Grouping
Weighting

Figure 4.2 Elements of the LCIA phase are mandatory or optional, depending on the goal of
the study (ISO 2006b).

• Natural Resources
• Natural Environment
• Human Health
• and often also, Man-Made Environment

Multiple impact pathways originating from the LCI link emissions and
extractions to impact category indicators. In practice, a category indicator is
the outcome of a simplified model of a very complex reality, giving only an
approximation of the quality status of the affected entity. Impact categories
and corresponding indicators can be organized at two levels along the cause-
effect chain: at a midpoint and at an endpoint level (Jolliet, Müller-Wenk et al.
2004) and (Bare and Gloria 2006). Figure 4.3 provides an example of a graphical
representation of the midpoint-endpoint framework as proposed by the ILCD
Handbook (EC-JRC 2010a).
Assignment of LCI Results to the Selected Impact Categories (Classification). In
this step, the inventory data are assigned to categories according to the impact
to which they are known to relate. If a substance contributes to more than one
impact category, then it is assigned to all of these categories in its entirety (that
is, it is not partitioned or allocated in any way). Such a case is, for example, the