Appendix C - LCA Tools and Methods

Commonly used LCA Tools

A 2006 survey of 65 LCA practitioners^[1] reported that:

58%* used GaBi (PE International)

31%* used SimaPro (PRé Consultants)

11%* used TEAM (Ecobilan)

Other tools cited:

·         BEES (NIST)

·         Umberto (ifu Hamburg)

·         ECO-IT (PRé Consultants)

·         Excel-based spreadsheets

·         Math package (e.g. MATLAB, Mathematica)

 

 

Impact Assessment Methodologies

Impact assessment methodologies are the systematic calculations that are used to get from an LCI (life cycle inventory) flow, such as carbon dioxide or sulfur dioxide, to the environmental impact that it causes. The results of these calculations typically measure either midpoint or endpoint effects (endpoint effects are sometimes called damage effects). For example, the following chart shows how some midpoint effects map to their respective endpoint effects^[2]:

 

 

While the endpoint or damage effects are the ones we really care about, these can be difficult to measure directly. For example, how many degrees of global average temperature increase are caused by one firm’s activities? It’s very hard to measure such a fractional effect, so we tend to measure the midpoint effect of greenhouse gas emissions, which lead to global average temperature increases. Most impact assessment methodologies use midpoint measurements. 

 

There are several impact assessment methodologies that are commonly used in the LCIA steps of an LCA, which include classification and characterization, and optionally normalization and/or weighting. Some of these impact assessment methodologies are described below.^[3]

 

 

CML (“CML 1996”, “CML 2001”)

The CML methodology, developed by the Institute of Environmental Sciences at the University of Leiden in the Netherlands, is the most widely-used and often considered the most complete methodology. It uses primarily European data to derive its impact factors. It groups the LCI results into midpoint categories, according to themes; these themes are common mechanisms (e.g. climate change) or groupings (e.g. ecotoxicity). There is a “CML 1996” and a “CML 2001” method. Its results can be viewed as a spreadsheet that presents characterization factors for more than 1700 flows (2001).

 

The CML impact assessment methodology is the one we have chosen to calculate the results for SolidWorks Sustainability.

 

For more information, see:

·         Institute of Environmental Sciences, Leiden University, The Netherlands: Handbook on impact categories "CML 1996", http://www.leidenuniv.nl/cml/ssp/projects/lca2/index.html

·         Institute of Environmental Sciences, Leiden University, The Netherlands: Handbook on impact categories "CML 2001 ", http://www.leidenuniv.nl/cml/ssp/projects/lca2/index.html

·         Institute of Environmental Sciences, Leiden University, The Netherlands: "Life Cycle Assessment, An operational guide to the ISO standards, Volume 1, 2 and 3",
http://www.leidenuniv.nl/interfac/cml/ssp/projects/lca2/lca2

 

Eco-Indicator (“95”, “99”)

Like the CML methodology, the Eco-Indicator method includes classification (“categories of effect”) and characterization steps, grouping the LCI results into midpoint categories.

 

These impact data are then weighted according to a social evaluation process. For example, the Eco-Indicator 95 method specifies that 1 death per 1,000,000 inhabitants is equal to 5% surface loss of an intact ecosystem. This weighting is performed in order to compare different types of environmental effects directly together; the results can then be presented as a single score, the so-called Eco-Indicator score.

 

Impact factors for Eco-Indicator 99 are collected and published in a spreadsheet by the Institute of Environmental Sciences, Leiden University, The Netherlands, and are furnished by PRé Consultants, makers of the Sima Pro LCA software package.

 

The data are then normalized, or divided by a common reference value, to facilitate communication. In the case of Eco-Indicator 95, the data are normalized after classification using the annual European contributions per inhabitant for the impact category. In Eco-Indicator 99, the data are normalized based on published information furnished by PRé Consultants^[4].

 

Because Eco-Indicator is a single-score LCA methodology, we do not include it as an option in SolidWorks Sustainability.

 

TRACI

The “Tool for the Reduction and Assessment of Chemical and Other Environmental Impacts”, or TRACI, is an impact assessment methodology developed by the US Environmental Protection Agency. As with the other impact assessment methodologies, TRACI is primarily a midpoint approach. It differs from the CML methodology in that the data comes primarily from North American sources. However, the TRACI methodology is not as comprehensive or complete as the CML method. For this reason, we have programmed SolidWorks Sustainability to perform the calculations using TRACI as well as CML, but haven’t enabled the TRACI results as an option.

 

The following is a handy chart that demonstrates the difference between single-score and multiple-indicator impact assessment methodologies.

 

 

 

 

 

 

 

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