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LCA part3

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the
phases of Inventory analysis, Impact assessment and Interpretation.
Part 3: Scientific background 68 May 2001
DEVELOPMENTS IN THE LAST DECADE
 
 
 ISO 14041 (1998E), clause 5.3.1 states the following concerning the scope of the study (see textbox):
Heijungs et al. (1992)
In Heijungs et al. (1992) scope definition did not yet constitute a separate method step. However, the level
of sophistication, or depth of the study as it was then called, comprised a separate element of goal
definition. A distinction was made between a more detailed and a more streamlined approach. A detailed
LCA was considered to be appropriate for important applications such as government approvals or bans.
A more simplified approach was considered to be appropriate for certain in-company applications and in
LCAs relating to product improvement and design. Simplification was to be achieved by:
- concentrating on the differences between product alternatives;
- excluding certain elements of the LCA;
- limiting the number of processes;
- limiting the number of environmental effects.
It was noted that introducing simplifications might imply decreased reliability, particularly if it is decided to
limit the number of processes or environmental effects examined, and that such reduced reliability should
be in conformity with the importance of the application. In Heijungs et al. simplified methods were not
elaborated in any further detail.
The spatial and temporal dimension of the study goal were treated as separate steps in Heijungs et al.
With regard to spatial representativeness it was noted that “this must be specified unless it is clear from
the specification of the functional unit. The spatial representativeness could be global, continental (e.g.
European), regional (e.g. EU), national (e.g. the Netherlands) or at company level (e.g. brand X). Also,
representativeness like ‘in temperate climates’ may be useful, e.g. in an LCA on insulation materials. The
particular spatial representativeness determines which alternative systems can usefully be considered in
an LCA study for a specific application (e.g. an LCA study on milk packaging for ecolabeling in the
Netherlands may involve different packaging alternatives from the same study for an EU ecolabel).”
With regard to temporal representativeness Heijungs et al. states that this should be determined similarly
to spatial representativeness. Generally, a rough indication will suffice, for example ‘1998‘ or ‘2010’. Also,
representativeness like ‘during summer’ may be useful, especially for seasonal products. Similarly to
spatial representativeness, temporal representativeness determines which alternative systems may
usefully be compared in an LCA study for a specific application.
Finally, Heijungs et al. already discussed a hot issue in the present LCA debate, which we shall
henceforth refer to as the “mode of analysis”. A basic assumption made by Heijungs et al. (p.12 of
Backgrounds ’92) is that the ceteris paribus principle is applied in product assessments, which means
that the choice of the functional unit of the product alternative investigated has no influence on any other
The scope of the study shall consider all relevant items in accordance with ISO 14040: 1997, 5.1.2.
It should be recognised that an LCA study is an iterative technique, and as data and information are
collected, various aspects of the scope may require modification in order to meet the original goal of the
study. In some cases, the goal of the study itself may be revised due to unforeseen limitations,
constraints or as a result of additional information. Such modifications, together with their justification,
should be duly documented.
Part 3: Scientific background 69 May 2001
ISO 14040 (1997E), clause 5.1.2 reads (see textbox):
The Scope definition is a relatively new step that has not yet received much attention in other LCA
literature. As explained in Section 1.4 and taking into account the elements distinguished as part of
Scope definition in ISO 14040 and 14041, we propose distinguishing two main elements of the scope of
the study:
- Determining the main characteristics of an intended LCA study: temporal, geographical and
technology coverage, coverage of economic processes, coverage of environmental interventions and
impact categories, mode of analysis and level of sophistication of the study.
- Reporting of all the main choices to be made in the ‘Function, functional unit, alternatives and
reference flow‘ step and the Inventory analysis, Impact assessment and Interpretation phases. This
yields a so-called Goal and Scope Report, drawn up for critical review and comments from
interested parties.
These two elements together cover all the ISO issues mentioned in the above text box. Below, the
developments of the past decade are discussed as they relate to the main characteristics: temporal,
geographical and technology coverage, mode of analysis and level of sophistication of the study. In Part
2a, guidelines are provided for drafting a Goal and Scope Report in Section 1.6 on reporting.
Temporal coverage
ISO 14041 (1998E), clause 5.3.6 states that temporal coverage refers to:
- The desired age of data (e.g. within the last five years) and the minimum length of time over which
data should be collected (e.g. one year).
According to ISO 14041 (1998E) the temporal coverage shall be specified and appropriate data quality
requirements defined. The latter point is treated in Section 3.5 of the Inventory analysis.
Temporal coverage has become even more important in recent years, as there is a general feeling today
that different modes of analysis should be employed for different temporal contexts (see also ‘Mode of
analysis’, below). It is thus important to specify a base year or base period for the study, on which other
choices can be based.
Geographical coverage
ISO 14041 (1998E), clause 5.3.6 states that geographical coverage refers to:
- Geographical area from which data for unit processes should be collected to satisfy the goal of the
study (e.g. local, regional, national, continental, global).
According to ISO 14041 (1998E) the geographical coverage shall be specified and appropriate data
quality requirements defined. The latter point is treated in Section 3.5 of the Inventory analysis.
In 1996 a ‘Groupe des Sages’ published a report on the use of LCA for ecolabeling applications in the
EU. They stressed the need to explicitly establish the geographical coverage of an LCA study in certain
cases, giving the example of regional differences in water hardness influencing detergent requirements.
Regional differences might thus be taken into account in determining the amount of detergent needed to
In defining the scope of an LCA study, the following items shall be considered and clearly described:
- the function of the system
- the functional unit
- the system to be studied
- the system boundaries
- allocation procedures
- the types of impact and the methodology of Impact assessment and subsequent Interpretation to be
used
- data requirements
- assumptions
- limitations
- the initial data quality requirements
- the type of critical review, if any, and
- the type and format of the report required for the study.
The scope should be sufficiently well defined to ensure that the breadth, the depth and the detail of the
study are compatible and sufficient to address the stated goal.
LCA is an iterative technique. Therefore, the scope of the study may need to be modified while the study is
being conducted as additional information is collected.
Part 3: Scientific background 70 May 2001
wash a certain amount of laundry optically white. Depending on the precise application of the LCA, this
may be a very useful thing to do since it will indicate to consumers how they can minimise the
environmental impact of their behaviour, taking into account the regional background (Udo de Haes et al.
,1996). The usefulness of including this geographical context depends on the application in question,
however.