Page 127 - Materials Chemistry, Second Edition

112 A. Bjørn et al.

the LCA report with reference to the outcome of the initial iteration. Transparency
on the selection of impact categories is essential to avoid an “interest-driven”
selection of impact categories where impact categories are excluded, e.g. because
they disfavour the product produced by the commissioner of a study in a com-
parative analysis.

8.8.2 Selection of LCIA Methods

To support the choice between alternative LCIA methods that can be used to
calculate an indicator score for the same impact category, ILCD has developed six
criteria for evaluating the methods:

1. Completeness of scope: how well does the indicator and the characterisation
model cover the environmental mechanisms associated with the impact category
under assessment?
2. Environmental relevance: to what extent are the critical parts of the impact
pathway included and modelled in accordance with the current state of the art?
3. Scientific robustness and Certainty: how well has the model been peer reviewed,
does it represent state of the art, can it be validated against monitoring data and
are uncertainties reported?
4. Documentation, Transparency and Reproducibility: how accessible are the
model, the model documentation, the characterisation factors and the applied
input data?
5. Applicability: are characterisation factors provided for the important elementary
flows for this impact category in a form that is straightforward to apply?
6. Stakeholders’ acceptance: has the model been endorsed by competent authori-
ties, are the model principles and applied metric understandable for users of the
LCA results in a business and policy contexts?
These criteria can be difficult to apply for LCA practitioners that are not experts
in LCIA modelling, but further insight can be gathered in Chaps. 10 and 40 gives an
overview of available LCIA methods, discusses their main differences and how they
perform on the six criteria.
In practice, an LCA practitioner will often rely on the use of software to model
the product system and perform the impact assessment and then simply calculate
LCIA scores for all the impacts categories that are made available in the software as
part of an LCIA method. An LCIA method is a collection of impact categories that
aims to have a broad coverage of environmental issues, and it is typically developed
by one research group (Hauschild et al., 2013). If several LCIA methods are
available, it may be useful to apply more than one to test the sensitivity of the
results to the choice of LCIA method (see Chap. 11). This is an easy way to explore
the sensitivity of LCIA results because calculating results for multiple impact