More about LCA
The aim for this section is to
give an overview of the LCA technique and not to give a comprehensive
description of LCA since there are several good textbooks available on this
LCA is a technique to assess the potential environmental impacts associated with
a product or service throughout its life cycle, by:
Goal and scope definition:
Defining suitable goal and scope for the LCA study.
Inventory analysis compiling
an inventory of relevant inputs and outputs of a product system.
Evaluating the potential environmental impacts associated with the selected
inputs and outputs.
LCA considers the
potential environmental impacts throughout a productís life cycle (i.e.
cradle-to-grave) from raw material acquisition through production, use and
disposal. Examples of categories of environmental impacts included in commercial
LCA software tools are resource use, human health and ecological consequences.
The limitations of the LCA technique can be overcome by complementing with other
tools and methods e.g. Environmental Risk Assessment.
The LCA study can assist in:
improvement opportunities for the studied product or service throughout its
Decision-making in industry,
governmental and non-governmental organizations.
Selection of relevant
environmental performance indicators and adequate measurement techniques.
Marketing opportunities for
products, e.g. to use LCA data for eco-labeling, environmental product
declaration (EPD), etc.
Standards ISO 14040-14043 provides principles, framework, and methodological
requirements for conducting LCA studies. The framework of LCA includes
definition of goal and scope, inventory analysis, impact assessment and
interpretation of the results, as illustrated in the figure below.
© ISO 1997, ISO 14040:1997(E)
and scope definition
The first part of an LCA study
consists of defining the goal of the study and its scope. The goal of the study
should include a statement of the reason for carrying out the study as well as
the intended application of the results and the intended audience. In the scope
of an LCA the following items shall be considered and described:
The function of the product
The functional unit.
The system boundaries.
Type of impact assessment
methodology and interpretation to be performed.
Assumptions and limitations.
Data quality requirements.
Type of critical review, if
Type and format of the
report required for the study.
The scope should
describe the depth of the study and show that the purpose can be fulfilled with
the actual extent of the limitations.
The functional unit is a
key element of LCA which has to be clearly defined. The functional unit is a
measure of the function of the studied system and it provides a reference to
which the inputs and outputs can be related. This enables comparison of two
essential different systems. For example, the functional unit for a paint system
may be defined as the unit surface protected for 10 years. A comparison of the
environmental impact of two different paint systems with the same functional
unit is therefore possible.
The system boundaries
determine which unit processes to be included in the LCA study. Defining system
boundaries is partly based on a subjective choice, made during the scope phase
when the boundaries are initially set. The following boundaries can be
Boundaries between the
technological system and nature. A life cycle usually begins at the extraction
point of raw materials and energy carriers from nature. Final stages normally
include waste generation and/or heat production.
Geographical area. Geography
plays a crucial role in most LCA studies, e.g. infrastructures, such as
electricity production, waste management and transport systems, vary from one
region to another. Moreover, ecosystems sensitivity to environmental impacts
differs regionally too.
Time horizon. Boundaries
must be set not only in space, but also in time. Basically LCAs are carried
out to evaluate present impacts and predict future scenarios. Limitations to
time boundaries are given by technologies involved, pollutants lifespan, etc.
Boundaries between the
current life cycle and related life cycles of other technical systems. Most
activities are interrelated, and therefore must be isolated from each other
for further study. For example production of capital goods, economic
feasibility of new and more environmentally friendly processes can be
evaluated in comparison with currently used technology.
Data quality requirements
Reliability of the results
from LCA studies strongly depends on the extent to which data quality
requirements are met. The following parameters should be taken into account:
Precision, completeness and
representativeness of the data.
reproducibility of the methods used throughout the data collection.
Uncertainty of the
information and data gaps.
Reusability of data is
also highly dependent on sufficient data documentation. One example of a format
for sufficient environmental data documentation is the LCI data documentation
software SPINE@CPM Data Tool and the LCI database SPINE@CPM Database. These
where developed within the CPM collaboration, in order to enable an effective
and efficient handling of environmental information. For more information about SPINE see
The ISO/TS 14048 data documentation format, described in reports found under
reports on this site, is another format for transparent, reusable documentation
focusing on data quality.
An interpretation of the CPM data quality requirements in terms of ISO/TS 14048
data documentation format.
reports about data quality can be found on:
Inventory analysis (LCI)
LCI comprises all stages
dealing with data retrieval and management (see figure below). The data
collection forms must be properly designed for optimal collection. Subsequently
data are validated and related to the functional unit in order to allow the
aggregation of results. A very sensitive step in this calculation process is the
allocation of flows e.g. releases to air, water and land. Most of the existing
technical systems yield more than one product. Therefore, materials and energy
flows regarding the process as a whole, as well as environmental releases must
often be allocated to the different products. This is recommended to be made
according to a given procedure:
allocation should be avoided.
Where allocation is not
avoidable, inputs and outputs should be partitioned between its different
functions or products in a way that reflects the underlying physical
relationships between them.
If the latter is not
possible, allocation should be carried out based on other existing
relationships (e.g. in proportion to the economic value of products).
The data collection is
the most resource consuming part of the LCA. Reuse of data from other studies
can simplify the work but this must be made with great care so that the data is
representative. The quality aspect is therefore also crucial.
© ISO 1998, ISO 14041:1998(E)
First examples of practical application of ISO/TS 14048 Data Documentation
Introduction and guide to LCA data documentation using the CPM documentation
criteria and the ISO/TS 14048 data documentation format.
Establishment of CPM's LCA database
Facilitating Data Exchange between LCA Software involving the Data Documentation
reports about ISO/TS 14048 and SPINE can be found on:
Impact Assessment (LCIA)
LCIA aims to evaluate the
significance of potential environmental impacts using the results coming out
from the LCI phase. The ISO14040 suggests that this phase of an LCA is divided
into the following steps:
Selection of impact
categories, category indicators and characterization models.
assignment of individual inventory parameters to impact categories, e.g. CO2
is assigned to Global Warming. Common impact categories are Global Warming,
Ozone Depletion, Photooxidant Formation,
conversion of LCI results to common units within each impact category, so that
results can be aggregated into category indicator results.
Normalization. The magnitude
of the category indicator results is calculated relatively to reference
information, e.g. and old products constitutes baseline when assigning a new
Weighting. Indicator results
coming from the different impact categories are converted to a common unit by
using factors based on value-choices.
Grouping. The impact
categories are assigned into one or more groups sorted after geographic
relevance, company priorities etc.
The methods that are usually
used for LCIA are e.g. EPS (Environmental Priority Strategies), ECO (Ecological
scarcity) and ET (Environmental Theme).
A Systematic Approach to Environmental Priority Strategies in Product
Development (EPS) Version 2000 - General System Characteristics
A Systematic Approach to Environmental Priority Strategies in Product
Development (EPS) Version 2000 - Models and Data of the Default Method
The aim of the interpretation
phase is to reach conclusions and recommendations in accordance with the defined
goal and scope of the study. Results from the LCI and LCIA are combined together
and reported in order to give a complete and unbiased account of the study. The
interpretation is to be made iteratively with the other phases.
The life cycle interpretation of an LCA or an LCI comprises three main elements:
Identification of the
significant issues based on the results of the LCI and LCIA phases of a LCA.
Evaluation of results, which
considers completeness, sensitivity and consistency checks.
In ISO 14040 standard it
is recommended that a critical review should be performed. In addition it is
stated that a critical review must have been conducted in order to disclose the
results in public.
For more information see
Organization for Standardization (ISO).