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

Historically, the evaluation of environmental impacts over the life of a product relied upon manufacturer claims, with some additional research needed perhaps on specific aspects of a product's composition and manufacture. Now, independently conducted life cycle assessments have emerged as important tools to creating genuine transparency for comparing the true environmental attributes between similar products. This has come about through the development of several fundamental aspects which are basic to an understanding of the LCA process:

International Standards

The International Organization for Standardization (ISO) (www.iso.org) has become recognized around the world for establishing LCA standards and rules. This organization, while an independent body, is actually a network of national standards organizations from many countries. In the United States, the American National Standards Institute (ANSI) is the member body that participates in and contributes to the standards that are promulgated under ISO. A process of global consensus is employed for these voluntary standards with the intentions of creating state-of-the-art specifications for products, services, and good practice, helping to make industries more efficient and effective, and helping to break down barriers to international trade. Since the founding of the ISO in 1947, they have published more than 19,500 International Standards covering almost all aspects of technology and business.

The life cycle phases of any material or product: extraction of raw materials, manufacturing into a finished product, construction, use in the building, and end of life disposal or recycling/re-use.

Image courtesy of CalStar Products, Inc.

The published standards in the ISO 14044 family specify requirements and provide guidelines for life cycle assessment (LCA), including: definition of the goal and scope of the LCA; the life cycle inventory analysis (LCI); the life cycle impact assessment (LCIA); the life cycle interpretation, reporting, and critical review of the LCA; limitations of the LCA; relationship between the LCA components; and conditions for use of value choices and optional elements. In much the same way that building products are tested by independent laboratories for any range of other characteristics, an ISO-compliant LCA is meant to be conducted by an independent third party following the requirements of the standard, thus ensuring unbiased results and confidence by end users of the results.

Impact Categories

Environmental impacts are organized into different categories to describe the effects during a product's life cycle (or individual phases) on specific areas of concern. These impacts include things like fossil fuel depletion (embodied energy), global warming (carbon footprint), water depletion, metal depletion, and various air pollution impacts. The ISO standard requires that specific environmental impact categories must be measured and included in the LCA and subsequently reported on.

Product Category Rules (PCR)

A product category rule (PCR) is the standardized method for conducting and reporting the results of a life cycle assessment for a specific type of product within the ISO guidelines. The PCR ensures that all products in a certain category (such as concrete products or metal roofing) are measured the same way in each life cycle phase and that environmental impacts are quantified in the same way for that category. The PCR defines the functional unit measured (e.g., one cubic yard of concrete or 100 square feet of roofing material) so equal comparisons can be made between individual products. PCRs are developed using a consensus-based, collaborative, transparent process by industry experts and stakeholders, following ISO guidelines. They are then verified by an expert review panel. At present, there are not a large number of PCRs since they can be expensive to develop; however, this is starting to change, and more PCRs are being developed each year for different categories of building materials and products.

Environmental Product Declaration (EPD)

Once a product has completed an independent LCA following the appropriate product category rule, if appropriate, then an Environmental Product Declaration (EPD) can be created by a manufacturer to document their overall sustainability and report the results of the verified LCA. This document is verified by a third-party expert and registered by an EPD program operator such as UL Environment (ULE) or the Institute for Market Transformation to Sustainability (MTS). EPDs enable architects, building owners, and other members of the design team to make accurate direct comparisons of the environmental attributes—such as carbon footprint and embodied energy—of similar products. Hence, products can be assessed when they may have the same traditional attributes (e.g. strength, durability, cost) but need to be selected and specified based on the lowest environmental impact of interest.

 

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Originally published in April 2013

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