Page 70 - Materials Chemistry, Second Edition

L1644_C02.fm Page 47 Tuesday, October 21, 2003 3:07 PM

TOTAL LCA
Raw Material

Air Emissions
PARTIAL LCA 1
Liquid
Emissions

Solid Waste
PARTIAL LCA 2

Energy Losses

Noise TOTAL LCA

Cradle Gate 1 Gate Grave
FIGURE 2.3 Boundaries in LCA.

described and assessed in a systematic way that allows other practitioners to under-
stand and reproduce the actual LCA. Initial data quality requirements must be done
with the assistance of the following parameters:

• Time-related coverage concerns a representative age (e.g., a period of 5
years) and minimum time frequency (e.g., annual).
• Geographical coverage means a geographic area from which data for a
process unit should be collected (local, regional, national, continental or
global) in order to satisfy the goal and approach (site specific or chain
specific) of the study.
• Technology coverage reflects the nature of the technology used in process
units. Depending on the product system and the goal of the study, a
technological mix should be used. In this case, the technology coverage
is considered, for example, as weighted average of the actual process mix,
best available technology or worst operating unit.

Further description that defines the nature of the data collected from specific
sites vs. data from published sources and whether the data are be measured, calcu-
lated (e.g., by material or energy balance) or estimated by similarity (from other
process units with similar operational conditions to that presented by the system in
study) will also be considered.
Data quality indicators such as precision, completeness, representativeness, con-
sistency and reproducibility should be taken into consideration in a level of detail
depending on the premises of the goal and scope definition step. Chapter 5 presents
and discusses some techniques of data analysis applied in order to assess the uncer-
tainty of the data to be used in the life-cycle inventory.

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