Page 59 - Materials Chemistry, Second Edition

2.2 Scope 43

Exercise: Provide an Equal Benefit of System Variants

The following two packaging systems for food are compared:
A) Polyethylene (PE)-containers with aluminium cover
B) Glass with screw-cap.
For simplification, only the main materials PE and glass are considered.
Make the following assumptions:
The non-negligible added value in the case of the PE container consists of the
fact that PE in the Duales System Deutschland (DSD) 34) system is collected and
can be used as energy source in the cement plant. Here, for example, light fuel
oil can be replaced. In the case of the glass container, 90% of the collected waste
glass is used for other glass products as secondary raw material.
Outline, in analogy to Figure 2.5, the overall systems to be examined, under
consideration of all benefits.

2.2.6
Data Availability and Depth of Study

Data availability and quality 35) are fundamental issues of the LCI Analysis and are
discussed in Chapter 3. In the goal definition it has to be decided which data will
presumably be available for the study, who collects or computes them and how,
if necessary, information on competitive products is to be procured. Further, it
has to be specified for which processes primary data are to be procured, for which
processes recourse to already existing data is possible and which data have to be
approximated by estimated values (see Section 3.4). Data availability is the most
important criterion to decide on the level of detail to which a study can be conducted
actually. Among the options to obtain meaningful statements with smaller data
36)
effort, mainly two are discussed :
1. Screening LCA
2. Simplified or streamlined LCA.

While formerly both terms were used rather synonymously, today screening
LCAs for the determination of the so-called hot spots are distinguished from
simplified LCAs (e.g. internal assessments). Both variants, which in practice are
often not distinguished, predominantly operate with easily available or estimated
data, also under omission of some life cycle stages, if necessary. This discussion
has been intensely conducted, particularly in the States, 37) but was also the topic
of a working group of the Society of Environmental Toxicology and Chemistry

34) German – ‘Duales System Deutschland’, dual system.
35) Fava et al. (1994).
36) Christiansen (1997).
37) Curran (1996), Curran and Young (1996), Weitz et al. (1996), Canter et al. (2002), Mueller,
Lamp´ erth and Kimura (2004), Hochschorner and Finnveden (2003, 2006) and Rebitzer (2005).