Page 174 - Materials Chemistry, Second Edition

158 3 Life Cycle Inventory Analysis

However, an LCA software cannot provide secure and adequate linkage of the
processes of the product system. The conductors of an LCA in general have to
correctly realize the logic of the product system before the actual calculation can
start. The user must not trust a software blindly. This is why the system check is
such an important step of the critical review procedure (see Section 5.5).

3.7.6
Calculation of the Life Cycle Inventory

If the system is modelled adequately and all process data records are available
in sufficient quality, the LCI of the examined product system can be calculated.
Tables 3.12–3.19 show as an example the LCI of the system variant 1-l-beverage
carton with closure related to the fU. 196)
In this list both inputs and outputs are indicated as elementary flows. Remember,
elementary flows are defined according to ISO 14040 and 14044 Section 3.12 as
material or energy entering the system being studied that has been drawn from
the environment without previous human transformation or material or energy
leaving the system being studied that is released into the environment without
subsequent human transformation

As supplement to these defined elementary flows, the LCI results CED
(Section 3.2.2) and use of natural land are included.
Nearly all LCA studies make use of newly procured as well as generic data of
diverse origin. Since the designation of inputs and outputs may vary even for the
same substance, the same substance may occur with different designations in an
LCA, for example: hexafluoroethane or perfluoroethane or C F . If the calculation
2 6
of an impact assessment is accomplished by means of a software, it must be
assured that all variants of the same substance are clearly assigned.
An LCI supplies much more data than used in the next phase, namely LCIA.
The reason is that the development of a scientifically justified transfer of LCI data
into impact indicators still does not allow a complete use of all LCI data (see
Chapter 4). It is thus even more important that the data of the LCI may not be
lost, for a retrieval of their information content within the interpretation phase
(see Chapter 5).
In Tables 3.12–3.19 the first step from LCI to LCIA is already represented, the
classification: The LCI parameters are assigned to the impact categories considered
in this specific LCA study serving as a praxis example (see also Section 4.6).

196) IFEU (2006) These detailed data have been provided for this book by courtesy of the IFEU.