Page 189 - Materials Chemistry, Second Edition

10 Life Cycle Impact Assessment 175

from different LCIA methods due to the difference in characterisation modelling,
units, numerical values, etc..)?
• When was the method published and have there been important scientific
advances in the meantime?
• Do I have the resources/data availability to apply a regionalised methodology
(providing more precise results)?
• Do I need to quantify the uncertainty of both LCI and LCIA and does the LCIA
method support that?
ISO 14040/14044 by principle do not provide any recommendations about
which LCIA method should be used, but some organisations do recommend the use
of a specific LCIA method or parts of it. The European Commission has established
specific recommendations for midpoint and endpoint impact categories by sys-
tematically comparing and evaluating all relevant existing approaches per category,
leading to the recommendation of the best available approach (EC-JRC 2011). This
effort resulted in a set of characterisation factors, which is directly available in all
major LCA software as the ILCD method. Some methods with a stronger national
focus are recommended by national governmental bodies for use in their respective
country, such as LIME in Japan, or TRACI in the US.
Given the amount of LCIA methods available and the amount of time required to
stay informed about them, it may be tempting to essentially stick to the method(s)
that the LCA practitioner knows best or has used for a long time, or that was
recommended by a colleague, or simply choosing a method requested by the client
to allow comparison with results from previous studies. It is however beneficial to
apply a more systematic approach to LCIA method selection that in combination
with the LCIA method comparison in Chap. 40 allows to determine the relevant
selection questions and criteria, thus optimising the interpretability and robustness
of the results of the study. The following properties are compared in Chap. 40 per
impact category and for both midpoint and endpoint LCIA methods:
• Aspects/diseases/ecosystems (which kinds of impacts) that are considered
• Characterisation model used
• Selected central details about fate, exposure, effect and damage modelling
• Reliance on marginal or average indicator
• Emission compartments considered
• Time horizon considered
• Geographical region modelled
• Level of spatial differentiation considered
• Number of elementary flows covered
• Unit of the indicator
Not all of these properties may be of equal relevance for choosing an LCIA
method for each practitioner or study, but they are identified here as relevant and
fact-based properties.