Page 213 - Materials Chemistry, Second Edition

4.3 Structure of Impact Assessment according to ISO 14040 and 14044 197

for example Germany, the releases per average inhabitant are smaller and the
numerical value ‘REQ per annual production’ is higher. Before numerical values
of different LCAs are compared with one another, it must, therefore, be examined
whether a common basis of underlying assumptions exists at all.
As a further possible example for a choice of reference values, ISO 14044
proposes a correlation with inputs and outputs of a reference scenario.
It has been shown in several publications 39) that a correct application of normali-
sation is by no means trivial.

4.3.3.2 Grouping
Grouping as an optional element of LCIA provides an option to summarize the
results of the preceding elements. Contrary to ‘weighting’ (Section 4.3.3.3) no value
choices should be included. ISO 14044 definition of grouping is little descriptive:

Assignment of impact categories into one or more sets as predefined in the goal
and scope definition, and it may involve sorting and/or ranking.
This suggests a formation of classes, which may include a ranking. Two possi-
bilities are indicated:
• to sort impact categories on a nominal basis (e.g. by characteristics such as inputs
and outputs or global, regional and local spatial scales) or
• to rank the impact categories in a given hierarchy (e.g. high, medium and low
priority).
It is expressly pointed out in the standard that ranking does after all depend on value
choices and therefore different persons, organisations and social groups may come
to different conclusions. These considerations clearly imply that this component
and (even more so) the following ‘weighting’ would be better integrated in the
component ‘Interpretation’. Unfortunately the revision of the ISO standards, which
transferred standards ISO 14040–43: 1997/2000 to ISO 14040–44:2006, neglected
these corrections.
Surprisingly the element Grouping is allowed for studies with ‘comparative
assertions’ intended to be made available to the public, whereas the next element
Weighting is not. The same ambiguity applies to the former standard 14042. 40)
This encouraged the German Federal Environmental Agency (UBA) Berlin to
develop a valuation method in accordance with the ISO standard. 41) It was ensured
that ranks for the individual impact categories were characterised verbally, not
by figures. These verbal ranks were derived from an analysis of environmental
endangering and of distance-to-target 42) between the status quo and political and
legal objectives concerning the environment. As an example this distance is very
low with regard to the impact category ‘stratospheric ozone depletion’ (successful
implementation of the protocol of Montreal of 1986 and subsequent amendments);

39) Sepp¨ al¨ aand H¨ am¨ al¨ ainen (2001), Erlandsson and Lindfors (2003) and Heijungs et al. (2007).
40) ISO (2000a)
41) Schmitz and Paulini (1999).
42) BUWAL (1998), Schmitz and Paulini (1999) and Sepp¨ al¨ aand H¨ am¨ al¨ ainen (2001).