Life Cycle Assessment of Building Products

New tools increase environmental transparency for verifiable sustainability
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Sponsored by CalStar Products, Inc.
Peter J. Arsenault, FAIA, NCARB, LEED AP

Before environmental considerations became paramount, architects typically chose products based on other specific features such as aesthetics, technical performance, and price. EPDs provide more information for consideration. For instance, in addition to selecting a product based on price and color, an architect can now also choose the product with the lowest carbon footprint, or embodied energy by directly comparing products' environmental impacts as outlined in their EPDs.

When it comes to reporting impact categories in the EPDs, the ISO requires eight categories at a minimum with the PCRs defining additional impact categories, if any, that must be included. Of course, EPDs can always report more impact categories than required by the PCR. Architects should consider which impact categories are of greatest interest for their projects. For instance, while carbon footprint is likely always a concern, in the arid southwest impact on water resources also might be of particular concern.

SMaRT© Sustainable Product Certification

Beyond the ISO standard, a more stringent product certification program has been developed in this country known as the Sustainable Materials Rating Technology (SMaRT©) Consensus Sustainable Product Standard©. This ANSI standard acts as a PCR to define a category of certified sustainable products. It was developed by the Institute for Market Transformation to Sustainability (MTS) and uses environmental, social, & economic criteria applied to manufactured products. (mts.sustainableproducts.com) To achieve SMaRT© certification, an ISO-compliant life cycle analysis is performed but some impact categories above and beyond those required by ISO must also be included, mostly related to human health and toxicity of materials used. Once complete, the LCA results are used together with other rating criteria to generate a LEED-style certification that is based on earning points in 6 categories:

  • Safe for Public Health & Environment (PHE)
  • Renewable Energy & Energy Reduction (RE&ER)
  • Biobased or Recycled Materials (MATLS)
  • Facility or Company Based (MFG)
  • Reclamation, Sustainable Reuse & End of Life Management (EOL)
  • Innovation in Manufacturing (IM)

Depending on the number of points received out of the 173 total that are possible, the product can be certified as follows:

Sustainable: 28-40 pts
Sustainable Silver: 41-60 pts
Sustainable Gold: 61-89 pts
Sustainable Platinum: 90-173 pts

Using the information from the LCA and the SMaRT© certification, the true sustainability and green attributes of a material or product become transparent and readily discernible, allowing for an informed assessment of the rated item and comparison between similar ones.

It is important to recognize that all of the parts of the process as discussed above are inherently tied together. Product category rules (PCRs) either created for a specific product type or utilizing the universal SMaRT PCR, are developed following the guidelines authored by ISO. A life cycle assessment (LCA) is then performed by an independent entity for a specific product or material according to the PCR. The PCR will identify the specific minimum impact categories that must be measured and accounted for. The results of the LCA are then used to publish an environmental product declaration (EPD) that comes from the manufacturer. When architects, engineers, or others request this EPD, then, it is a representation that the proper process has been followed to produce it. It is the EPD that ultimately is used by the design team to assess different products and materials for sustainability and to provide documentation for green building certification programs.

LCAs and EPDs have long represented the future of product evaluation for sustainable projects and materials. With growing calls for product transparency and the role transparency will likely play in LEED version 4, these tools are beginning to take their rightful place in the mainstream selection of materials. LCAs and EPDs provide standardized methods for verifying manufacturers' environmental claims and allow for accurate side-by-side product comparisons. As such, LCAs and EPDs are possibly the best way to ensure true green construction and prevent “greenwashing.”

Life Cycle Boundaries

Since EPDs present the results of the LCA, it is necessary to understand which phases of a product life cycle are included or specifically excluded for comparison purposes in the LCA and EPD report. The term “boundaries” is used to categorize the grouping of the life cycle phases, with EPDs typically showing information with one of the following three sets of boundaries:

Cradle-to-Gate

The scope of this LCA considers raw material extraction and its transportation plus the manufacturing process, including energy to create the plant's operational energy. In essence, it analyzes the product from raw material (cradle) to the point where it is ready to be shipped (gate). In basic terms, this is the portion of the life cycle that manufacturers have the most control over and can most accurately provide information on.

The typical life cycles of concrete are shown in this diagram with the boundary of “cradle to gate” indicated. If the transportation of that concrete were added to the analysis, it would become “cradle to job.” If the entire life of the concrete was being assessed, it would include all phases including construction, use, and end of life, making it a cradle-to-grave LCA.

Image courtesy of CalStar Products, Inc.

 

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Originally published in April 2013

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