Page 71 - Materials Chemistry, Second Edition

66 4. Life cycle sustainability assessment: An ongoing journey

scope definition, inventory analysis, impact assessment (involving the four steps: classifica-
tion, characterization, normalization, and analysis of data quality) and interpretation.

4.3.1.4 Functional unit and system boundaries
It is a very important point that different life-cycle based methods for sustainability assess-
ment (Kl€ oepffer, 2008) have to have the consolidated approach in the functional unit defini-
tion and use consistent—ideally identical—system boundaries. The primary purpose of a
functional unit is to provide a reference to which the inputs and outputs are related, ensuring
the comparability of LCSA results and defining the quantification of the identified function of
the product/process/services. Also, in an LCSA, the inventory and impact indicators must be
related to a common product functional unit, which is the basis of all techniques described. As
with the S-LCA (UNEP/SETAC, 2011), it is recommended that the functional unit describes
both the technical utility of the product and the product’s social utility.
LCSA system boundaries must be defined according to the following definitions, which
are well known in any life cycle thinking and life cycle assessment study:

• from cradle to gate, which means to collect data and information from raw material
extraction to manufacturing and assembling of the product;
• from cradle to grave, from raw material extraction to their return to the environment as
waste or emissions;
• from gate to gate, considering only what is inside the fence of the company, excluding
supply and distribution;
• from gate to grave, which includes distribution phase, use, and end of life phases; and
• from cradle to cradle, which means to assume a circular economy perspective, thanks that
all outputs (such as emissions, water, and waste) produced at end of life return in input,
closing the loop.
It is recommended, whenever feasible, that a combined framework for impact assessment
based on the individual S-LCA, LCC and (environmental) LCA frameworks is used (UNEP/
SETAC, 2011).

4.3.1.5 Quali-quantitative inventory data
The assumption that primary data are the best option both from a qualitative and quanti-
tative point of view seems to be definitely true also for LCSA. At the same time, complete and
a
effective existing databases, such as Ecoinvent or the European ILCD (Life Cycle Database of
the International Life Cycle Data System) providing a common basis for consistent, robust,
and quality-assured data and studies, can contribute to the correct completion of all data-
collecting catalogs. Inventory analysis involves data collection and calculation procedures
to quantify relevant inputs and outputs of a product system. The process of conducting an
inventory is iterative. Data must respond to main properties such as precision, completeness,
temporal consistency, geographic and technological connection.
If for LCA and LCC a quantitative approach is perfectly recognized as possible and useful,
on the contrary, there is a wide debate about the opportunity to utilize quantitative inventory

a
See Ecoinvent (2003).