Page 347 - Materials Chemistry, Second Edition

5.2 The Phase Interpretation According to ISO 331

5.2
The Phase Interpretation According to ISO
5.2.1
Interpretation in ISO 14040

9)
In Section 5.5 of the framework of ISO 14040, interpretation is described as
follows:
Interpretation is the phase of LCA in which the findings from the inventory
analysis and the impact assessment are considered together or, in the case of LCI
studies, the findings of the inventory analysis only. The interpretation phase should
deliver results that are consistent with the defined goal and scope and which reach
conclusions, explain limitations and provide recommendations.
It is to be noted that life cycle inventory studies as well require a final phase, that is,
‘interpretation’. In the second paragraph of Section 5.5, the following is recalled:
… the LCIA results are based on a relative approach, they indicate potential
environmental effects, and they do not predict actual impacts on category endpoints,
the exceeding of thresholds or safety margins, or risks.
This includes a warning of over-interpretation of results of the impact assessment.
This ‘wagging finger’ stretches through the entire 14040 framework.

5.2.2
Interpretation in ISO 14044

The steps of interpretation in ISO 14044 10) in Section 4.5 are composed of
1. identification of the significant issues based on the results of the LCI and LCIA
phases of LCA;
2. an evaluation that considers completeness, sensitivity and consistency checks;
3. conclusions, limitations and recommendations.
Interrelations of these steps and to LCA phases 1–3 (see Chapters 2–4) are
schematically illustrated in Figure 5.1. Applications are out of scope of an LCA and
not referenced (Figure 1.4).
According to Figure 5.1, the identification of significant parameters is the direct
result of the three preceding phases of an LCA and is interrelated with the
evaluation. Besides, information from phase 1 is necessary for the adaptation to the
objective of the study. This reflects the insight that no LCA matches another: each
depends on the objectives of phase 1 (definition of goal and scope). Therefore, the
evaluation can only take place within the coverage of the goal and scope definition,
which can, however, be adapted, owing to the iterative approach of the method,
if during the study it is realised that the original prerequisites do not meet the
objectives (e.g. if important data cannot be procured).

9) ISO (2006a).
10) ISO (2006b).