Page 135 - Materials Chemistry, Second Edition

3.4 Procurement, Origin and Quality of Data 119

should not be underestimated in relation to effort and significance to the final
result.
How can it be done practically? With regard to ‘material’ products (goods),
the product description is the first step; with respect to an ‘immaterial’ product
(service), it is the flow of activities. In both cases upstream material flows and
downstream waste flows are described.
For material products (goods), a product description indicates which materials
in which quantities are used, referred, for example, to piece, mass or another
meaningful unit. These data have to be procured in a way that is easy to convert
to the reference flow according to the fU. To better understand the product
system, both the inspection of the product as well as sketches and plans on the
functioning of materials and manufacturing processes are useful and should be
documented.
Knowledge of the materials and their share in the product may in some
cases already allow a first rough estimation of the order of magnitude of envi-
ronmental loads: should inventory data record for all included materials be
available as generic data in a data base these can be aggregated according to
their share in the product. An aggregation in the simplest case is the addition.
For this first estimation the CED is suited as a parameter (see Section 3.2.2).
As none of the life cycle phases of production, use, and disposal are consid-
ered in detail, and no specific data on transport are available, these calculations
serve as an orientation for the orders of magnitude which can be expected,
nothing more.
The next step would be a system analysis with a differentiated elaboration of the
system flow chart and the cut-off of ancillary branches according to the cut-off criteria
chosen. The unit processes identified are the basis for data procurement. All inputs
and outputs to every unit process have to be identified. If a preliminary system
analysis has already been conducted during the goal and scope definition, it has
now to be expanded and refined. The result will be a differentiated system flow
chart (see Section 3.7.3).
At this state of work a screening-LCA 127) might be worthwhile if a comprehensive
LCAisintended.

3.4.2
Procurement of Specific Data

It is rarely ever possible to procure all data as primary data, that means to gather
specific data at specific plants for specific processes. Therefore a real LCI always
consists of primary data, generic data and, where the one or other is not available,
of estimations 128) (see Section 3.4.3.1). For all these data sets, the documentation of
their origin and quality is essential, because comprehensibility and transparency
are central requirements according to ISO 14040/44. 129)

127) Christiansen, 1997.
128) Bretz and Frankhauser, 1996.
129) European Commission, 2010; Sonnemann and Vigon, 2011.