Page 16 - Materials Chemistry, Second Edition

Goal and Life cycle assessment: origins, principles and context 3
scope definition

Inventory Interpretation
analysis

Impact
assessment

Figure 1.1 Outline of generic life cycle assessment (LCA) process (after ISO 14040, 2000a).

tional Organization for Standardization (ISO) definition provides some indication, although
it is self-referencing: ‘compilation and evaluation of the inputs and outputs and the potential
environmental impacts of a product system throughout its life cycle’ (ISO 1997, p. 2). Generic
LCA method requires that all the main inputs to the processes that provide the service are
taken into account, as well as the processes and materials that feed into those processes, and so
on back ‘up’ the supply chains of the various materials in the product to the raw resource
inputs. These raw inputs are invariably energy-based – the coal mine or oil well – rather than
simply raw materials. For example, making bricks may require brick clay and an extraction
quarry, but this process operates with fossil fuel-powered machinery. Hence, although bricks
are made from quarried clay and other materials, at the end of this process is the oil well or
coal mine required to drive the steel mill to make the machinery used in clay extraction.
International standards assist in the specification, definition, method and protocols associ-
ated with undertaking, reviewing and reporting LCA studies. ISO 14040 describes the princi-
ples and framework for life cycle assessment. The original standard (produced in 1997) was
updated in 2006 (ISO 2006a). This ‘core’ standard includes guidance on defining the goal and
scope of an LCA study, development of the life cycle inventory, the life cycle impact assessment,
and interpretation (Fig. 1.1). It also indicates reporting and critical review parameters and
limitations of LCA. However, it does not describe the LCA technique in detail, nor does it
specify how to undertake individual phases of the LCA. More detail is provided in ISO 14044
(ISO 2006b), which together with ISO 14040:2006 replaces other former LCA-related stand-
ards (ISO 14040:1997, ISO 14041:1999, ISO 14042:2000 and ISO 14043:2000). Further stand-
ards deal with issues such as data documentation formats. Additional guides to the standards
seek to provide more detail on their application in practice (e.g. Guinee 2002). However, not all
regions have adopted the updated standards at the time of writing (e.g. Australia and New
Zealand, AS/NZS ISO 1998).
For any LCA, appropriate framing of the key ‘question’ forms part of the definition of the
goal and scope, including setting the functional units of the study. For example, a comparative

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