Life Cycle Analysis & Green Building: Credibility at The Crossroads

Tom Lent - September 16, 2004

The Sustainable Products Purchasing Coalition (SPPC)[1] hopes to catalyze the market for sustainable products by getting consistent environmental performance data from manufacturers. They've chosen to do this through an Eco-Profile - a standardized form through which manufacturers can provide Life Cycle data for their product compatible with the variety of accepted Life Cycle Analysis (LCA) tools currently in use in the industry.

Comparable impact information is the holy grail of LCA development and the SPPC has launched one of the most credible efforts to make it usable for designers and purchasers. Just how hard this is going to be, however, was evident last week at a conference entitled "Crossroads, The Intersection of Green Building and Life Cycle Assessment," co-sponsored by SPPC and the Cascadia Chapter of the U.S. Green Building Council.[2]

Quantitative LCA tools have become an effective means for industrial design analysis. The application of these tools to material selection by the architectural community, however, presents significant challenges that have not yet been overcome. Current LCA tools can give the user a false sense of security that the tool is providing a comprehensive, unbiased and final analysis of all of the environmental impacts resulting from production, use and disposal of a material, ending the need to ask further critical questions. In reality, serious data and analysis limitations inherent in current tools can lead users to strong but hidden biases for materials with major environmental health impacts that are inadequately quantified. Without proper acknowledgement of these constraints, LCAs can turn environmental values upside down.

Take current manufacturer claims that BEES, a U.S. government-sponsored LCA, proves that PVC-based vinyl flooring (VCT) has less environmental impact than natural linoleum.[3] This may be a bit surprising to those familiar with analyses that find PVC to be the worst plastic for the environment.[4] That's because the European industry model used by BEES to calculate the manufacturing impact of PVC conveniently left out the carcinogenic dioxin emissions, thus tilting the analysis in favor of PVC.[5] This is a particularly serious omission as dioxin is the most potent synthetic carcinogen measured by science and subject of international treaty efforts (signed by the U.S.) to stop its production[6]. As a result, good intentions to do the right thing for the environment are thwarted, and twenty years worth of environmental policy making on dioxin is undermined every time a green building professional relies upon this information to select vinyl over linoleum.

The inherent complexity and limitations of LCA have led some experts and numerous manufacturers to devise alternative decision making tools which employ chemical screens -- blacklists if you will -- that align design standards with agreed upon environmental health policy goals, such as the elimination of dioxin and other chemicals of concern.[7] Presently, chemical screening systems offer the practitioner the most useful and credible guidance on the environmental health impact of material selection and are critically necessary in the face of LCA's blind spots and pitfalls.


Footnotes

[1] SPPC represents over a billion dollars in purchasing power from progressive municipalities such as Santa Monica, CA, Seattle, WA, Portland and Eugene, OR. (www.sppcoalition.org)

[2] "Crossroads - The Intersection of Green Building and Life Cycle Assessment," http://www.sppcoalition.org/CrossroadsFlyer_1.pdf

[3] Armstrong Flooring web site: "The BEES model has consistently rated VCT as one of the best products in overall floorcovering performance", http://www.armstrong.com/common/c2002/content/files/2958.pdf.

[4] Healthy Building Network, "PVC fact sheet", http://www.healthybuilding.net/pvc/index.html.

[5] Tom Lent "Toxic Data Bias and the Challenges of Using LCA in the Design Community" USGBC GreenBuild Conference 2003, http://www.healthybuilding.net/pvc/Toxic_Data_Bias_2003.html.

Careful comparison of the BEES impact categories reveals that VCT actually performs worse than linoleum in every category in which either of the materials has a significant impact, except eutrophication Ð excess nutrient runoff. In fact, linoleum even outperforms VCT on fossil fuel depletion despite the fact that linoleum currently is imported from Europe. http://www.healthybuilding.net/theconduit/archives/000020.html.

Nonetheless, although the eutrophication number is in dispute and may be off by an order of magnitude or more it serves to outweigh all the other categories when BEES combines impacts for a total score.

[7] Cradle to Cradle Benchmarking, http://www.mbdc.com/prod_pc.htm; "McDonough Braungart Materials-Assessment Protocol Being Used to Examine Shaw's Eco Products", http://www.buildings.com/Articles/detail.asp?ArticleID=1322 [link no longer available]; "Design for the Environment", http://www.hermanmiller.com/CDA/SSA/Category/0,1564,a10-c609,00.html.

For more analysis of the challenges and limitations of LCA analyses of PVC, see also "Reaching the Limits of Quantitative Life Cycle Assessment," Mark Rossi's critique of a recent LCA assessment of PVC released by the European Commission, http://www.healthybuilding.net/pvc/CPA_EC_LCA_Critique.html.


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