Page 153 - Materials Chemistry, Second Edition

3.7 Illustration of the Inventory Phase by an Example 137

3.7
Illustration of the Inventory Phase by an Example
Many of the following procedures are integrated into LCA software tools in one
form or other. Graphical user interfaces for the modelling of systems and definition
of the arithmetic rules are common practice to date. This fact does not, however,
release the practitioners from carefully conducting all steps, as otherwise faults
occurring during software operation may not be identified. With regard to the
content, the following items must be considered:

1. Detailed description of the examined product system (Section 3.7.1): Which
materials in the product system in which quantities and related to the fU are
to be considered? Which waste flows and which transportation? The fU and
the respective reference flows that were determined in the phase ‘definition of
goal and scope’, should again be critically checked and adapted if necessary.
2. Analysis of the manufacturing processes, waste utilisation and disposal tech-
nologies and other relevant processes of the product system (Section 3.7.2):
Procurement of primary data and ensuring the availability of generic data.
Transfer of the operationally procured primary data into data records of unit
processes. Characterisation of the data records concerning origin, quality and
system boundaries (technically, geographically and temporarily). Ensuring that
the data relevant for impact assessment have been procured as inputs and out-
puts of the unit processes: impact categories and associated indicators have
already been defined in the phase ‘definition of goal and scope’ (they will be
extensively discussed in Chapter 4).
3. Elaboration of a differentiated system flow chart including reference flows
(Section 3.7.3): In this step the sizes of the unit processes can be specified.
If generic data for complete life cycle sections are available in appropriate
quality, for example, the production of LDPE from raw material to LDPE
pellets, the production of LDPE pellets can be treated as a single unit process
(see Section 3.1.3).
4. Allocation rules (Section 3.7.4):
In an LCA, allocation rules, according to ISO 14040/44, are already defined
in the phase ‘definition of goal and scope’. As, for a better understanding,
‘allocation’ is discussed in Section 3.3, the specifications of the sample study
are presented here. They are:
a. Definition of allocation rules on process level for multi-output and multi-
input processes;
b. Definition of allocation rules on system level for OLR;
c. Definition of the rules for obtaining equality of benefit during waste
treatment.
5. Modelling of the system (Section 3.7.5):
Definition of the arithmetic rules with consideration of allocation rules by
which the unit processes are to be interlaced.
6. Calculation of the inventory (Section 3.7.6):