Page 120 - Materials Chemistry, Second Edition

8 Scope Definition 105

activities, and a small quantity of radioactive waste, e.g. from hospital equipment,
can require extensive waste treatment, and therefore be associated with environ-
mental impacts that should not be neglected.
Due to the limitations of working with quantitative completeness requirements,
we here advocate a qualitative approach. This means specifying the parts of a life
cycle that must be included in the system boundaries and arguing why cutting off
other parts is acceptable. For example, an LCA practitioner may know from similar
LCA studies or previous experience that transportation between the use stage and
the waste management stage, or business trips of the employees of a tier-one
supplier are negligible. For new LCA practitioners, it can be difficult to create
reasonable completeness requirements and it is therefore always important to
explicitly report and justify them. Applying the iterative approach, the omission of
any processes should be justified in a sensitivity analysis after the inventory
analysis and impact assessment. If the sensitivity analysis indicates that the process
may be important with the chosen completeness requirements, it should be included
(and perhaps refined) in the next iteration. We stress that an LCA practitioner
should not blindly apply “default” qualitative completeness requirements, such as
disregarding the production and maintenance of infrastructure, to any study, but
always base the requirements on a case-specific assessment. This is to avoid cutting
off parts of a life cycle that are important in the specific study, although they may
typically not be important.
As with most items of the scope definition, completeness requirements are meant
to guide the initial LCI analysis, but during this analysis unforeseen limitations may
mean that the requirements are in practice not possible to follow. The LCA prac-
titioner can either handle this situation by modifying the completeness requirements
in a new iteration of the scope definition or by explicitly documenting in the LCI
analysis the parts of the LCI model that do not fulfil the completeness requirements.

8.7 Representativeness of LCI Data

It is the aim of LCA to reflect physical reality. This means that the model should
represent what actually happens or has happened to the extent possible, and the unit
processes applied to model the product system must be representative of the pro-
cesses which are actually used in the analysed product system (in case of attribu-
tional LCA) or affected due to the introduction of the assessed product on the
market (in the case of consequential LCA).
Typically, parts of a foreground system will be based on data (elementary flows,
etc.) collected first-hand by the LCA practitioner, e.g. from the company commis-
sioning the study. This primary data is, provided that it contains no errors, per
definition representative of the specific process occurring at the time that the data
was collected. Other parts of the foreground system and the entire background
system, on the other hand, are constructed from other than first-hand data sources
and when doing so it is important to consider how representative the chosen or