Page 91 - Materials Chemistry, Second Edition
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76 A. Bjørn et al.
8.1 Introduction
The scope definition determines what product systems are to be assessed and how
this assessment should take place. Together with the goal definition (Chap. 7) the
scope definition serves as a firm guide for how the ensuing LCA phases should be
performed (Inventory analysis, Impact assessment and Interpretation, including
uncertainty and sensitivity analysis) and for how the LCA should be reported. An
overarching aim of the scope definition is to ensure and document the consistency
of methods, assumptions and data and strengthen the reproducibility of the study.
A scope definition consists of the following nine scope items:
1. Deliverables
2. Object of the assessment
3. LCI modelling framework and handling of multifunctional processes
4. System boundaries and completeness requirements
5. Representativeness of LCI data
6. Preparation of the basis for the impact assessment
7. Special requirements for system comparisons
8. Needs for critical review
9. Planning reporting of results.
Each item must be considered when performing an LCA. Items 2–6 are central
for doing an LCA because these have a pervasive influence on decisions made in
later LCA phases. Aspects 1, 7, 8 and 9 mainly relate to reporting and commu-
nicating an LCA study. For these items, we further refer to Chaps. 13, 37–39,
which provide specific guidance on the reviewing and reporting of LCAs. Note that
the aspect of data quality requirements, which ILCD proposes as a separate scope
item, is here considered under scope items 4 and 5.
8.2 Terminology and Key Concepts
Before explaining the nine scope items, we present the terminology and key con-
cepts that are used in this chapter.
8.2.1 Unit Process and Flows
A unit process is the smallest element considered in a life cycle inventory model
(see below) for which input and output data are quantified. Unit processes can
therefore be considered the building blocks of a life cycle inventory model that are
“glued together” by input and output data, which can be organised into six cate-
gories of physical flows:
