Page 206 - Materials Chemistry, Second Edition

190 4 Life Cycle Impact Assessment

models, it should not, however, replace a thorough study of literature on the current
state of the art.
ISO 14044 further recommends that impact categories, category indicators
and characterisation models are to be internationally accepted, based on interna-
tional agreement or are recognised by an authorised international board. Possible
candidates at present are the SETAC (Society of Environmental Toxicology and
Chemistry) and the UNEP/SETAC Life Cycle Initiative. These are mere recommen-
dations. If taken literally, new categories, indicators, and so on, under development
cannot be tested in practice. Actually, this excerpt of the standard often serves as
an excuse to exclude certain impact categories. An analysis of the LCIA methods
(per impact category) and methodologies (sets of impact methods) is provided in
the handbook published electronically by the European Commission (EC). 22) It is
planned to publish recommended methods that may be binding for official LCAs
ordered by the Commission. Such a binding list would, of course, violate the
international standard (see above) stating that the impact categories, and so on, are
selected in the phase Goal and Scope. Similar considerations may be appropriate
for the recently proposed ‘Product Environmental Footprint’ (PEF) 23) to be tested
in 2014–2017.
It is further noted that categories and indicators should be based on as little
value choices and assumptions as possible (that means scientifically objective),
double counting should be avoided, environmental relevance exists and so on.
These partially redundant enumerations of ISO 14044, Section 4.4.2.2.3 can be
explained by the fear of manipulation of the method, an underlying issue of all
LCA standards. 24)

4.3.2.2 Classification
Classification is a correlation of inventory items to impact categories, for example,
GHGs to the impact category climate change or acid-forming gases to the impact
category acidification. Besides output-relevant releases from the technosphere into
the environment, inputs from the environment into the technosphere have to be
assigned to the extent of their procurement in the inventory. An example is the
assignment of fossil raw materials to the impact category resource demand. The
most important impact categories are discussed in detail in Section 4.5 with regard
to their indicators and characterisation models.
Figure 4.2 shows the principle of classification and the subsequent phase of
characterisation.
Classification according to ISO 14044 includes as a mandatory component 25) a
differentiation between inventory results that can be assigned to only one impact
category, and an identification and assignment of results that refer to more than
one impact category. Within the latter it should be possible to distinguish between
parallel impact mechanisms (e.g. SO as a toxic substance and as acid-forming gas,
2
22) European Commission (2010).
23) European Commission (2013).
24) Kl¨ opffer (2005, 2012a).
25) ISO (2006b, Section 4.4.2.3).