Page 36 - Materials Chemistry, Second Edition

AN OVERVIEW OF THE LIFE CYCLE ASSESSMENT METHOD 17

The standards are organized into the different phases of an LCA study. These
are:

• Goal and scope definition
• Inventory analysis
• Life cycle impact assessment
• Life cycle interpretation

The relationships between these phases have been illustrated in a figure,
and this figure has become a type of logo of LCA (Figure 2.1).
Typically, LCA starts by defining goal and scope, then proceeds to the inven-
tory analysis, then optionally continues to impact assessment, and it ends
with the interpretation. However, as indicated in Figure 2.1, an LCA study is
a highly iterative process, so that the LCA practitioner may need to go back
to goal and scope after the preliminary inventory work, to move back from
impact assessment to inventory analysis, to have a look at the interpretation in
an early stage, etc.
Below, we will discuss the main idea and content of the four phases in sep-
arate subsections. All quotations are taken from the ISO documents, unless
otherwise indicated.

2.1.1 Goal and Scope Definition
There is no explicit ISO definition of the first phase of LCA. However, it obvi-
ously centers around formulating the question and stating the context of
answering this question. In the goal and scope definition, no data is collected
and no results are calculated. Rather, it is a place where the plan of the LCA
study is defined as clearly and unambiguously as possible. Likewise, in an
LCA report, it should help the reader to quickly find out the precise question
addressed and main principles chosen.
The goal of the LCA should deal with the following topics:

• the intended application;
• the reasons for carrying out the study;
• the intended audience;
• whether the results are to be used in comparative assertions
disclosed to the public.

The choices made here have an influence on the rest of the LCA procedure.
For instance, depending on the intended audience, a critical review may be
needed, and it may be important that an external expert takes this task.
In the scope definition, a number of major choices are made. First of all,
the product system or systems to be studied, and the function the system
delivers (or in case of a comparative LCA, the functions the systems deliver).
For instance, one might be interested in the product systems incandescent light
bulb versus the LED bulb, with the function of lighting a room.