One of the emerging knowledge-based tools being positioned by the green-building industry for environmental assessment, evaluation and specification of building products is the life-cycle-assessment calculator. LCA is an approach that considers the entire value chain involved in producing, using and disposing of a product. It was created to assist manufacturers and designers with reporting data points, such as energy consumption and related greenhouse-gas emissions.

The movement toward LCA is in part a result of a perfect storm surrounding the inconsistent application of sustainability standards. Environmental product evaluation has become confusing because green rating systems award points or credits for single product attributes, such as recycled content or low VOCs. This further is compounded by design firms and contractors providing manufacturers with sustainable-product questionnaires, none of which are exactly the same. Manufacturers are self-reporting information to the best of their understanding and garnering expensive third-party certifications. Those factors have led to greenwash, which propagates false or insufficient information from manufacturers. In 2004, the Washington, D.C.-based U.S. Green Building Council began the process of determining how best to integrate LCA into its LEED rating system. LEED 2009 integrates LCA as an Innovation credit within a pilot program. This is the first step in an evolution that moves away from single-attribute assessment to multiple attributes and service life. Green Globes, the green-building rating system of the Portland, Ore.-based Green Building Initiative, is reviewing public comments about several system attributes, including the availability of more than 30 points for use of the EcoCalculator, an LCA tool developed by the Merrickville, Ontario, Canada-based Athena Sustainable Materials Institute for material consideration of building envelopes. LEED’s LCA consideration also is based on EcoCalculator. Although LCA calculators are the latest tools captivating the green-building industry, it is important to recognize LCAs contain many uncertainties and information gaps. In fact, because today’s LCA calculators mainly focus on products, rather than whole building systems, these tools are limited from the start.

LCA UNCERTAINTIES

It is important to frame LCA to understand information gaps and potential uncertainties in the reported data. LCA was designed in the early 1970s to improve manufacturing processes and was largely responsible for getting thearchitecture, engineering and construction industry to better understand environmental impacts. The LCA process is a systematic, phased approach that consists of four components: goal definition and scoping, inventory analysis, impact assessment and interpretation. These four phases of LCA afford practitioners latitude in reporting of data outcomes depending on the LCA scope, boundaries and functional units. The most effective way to achieve long-term environmental results is through the use of a consistent set of metrics and decision-making framework. The Washington-based U.S. Environmental Protection Agency has developed Tools for the Reduction and Assessment of Chemical and other Environmental Impacts, or TRACI, to assist in determining impacts for sustainability metrics, LCA, industrial ecology, process design and pollution prevention. TRACI includes impactassessment methodologies for ozone depletion, global warming, acidification, eutrophication, troposphere ozone formation, ecotoxicity, human particulate effects, human carcinogenic effects, human non-carcinogenic effects, fossil-fuel depletion and land-use effects. Although TRACI provides a consistent framework with which to perform an LCA, weighting these impacts involves assigning subjective, value-based factors to the different impact categories based on their perceived importance or relevance. Determining and weighting impacts based on specific scope, boundaries and functional units creates complexity that makes it unlikely there will be continuity in data outputs, other than process, from one manufacturer to another. Complete LCA inventories, known as LCIs, collect data about commonly used materials, products and processes that can be used to develop product LCAs, systems and tools. LCIs often require use of data considered proprietary by the manufacturer of a product or upstream suppliers or vendors. LCA practitioners performing a study often are forced to use existing databases when this occurs. As a result, current LCIs often contain insufficient source and documentation data, which does not permit technically sound external review. This circumstance is a strong argument for peer-reviewed, association-aggregated, baseline LCA data that can more accurately populate LCI databases. Currently, there is much more reliable LCI data available in Europe and Canada than in the U.S. Much of this information has been adjusted with U.S. data to populate the U.S. LCI database, which is maintained by the National Renewable Energy Laboratory, Golden, Colo. Because not all industry has conducted LCAs, a lack of accurate American-industry data adversely affects the credibility of all LCIs. The U.S. LCI is profiled as representative data because of uncertainties about data sources.

INFORMATION CHALLENGES

In an excerpt from the book, Green Building: Project Planning & Cost Estimating, Mark Kalin, FCSI, writes the responsibility for selecting and specifying green-building products lies with the entire building team. He notes this requires a comprehensive evaluation that goes beyond data points of LCA and studies materials from a whole-building- design perspective. A building team should have a thorough understanding of all a product’s attributes—environmental, performance and economic—to avoid unintended consequences when one makes single-issue decisions. For example, consider the search for a highperformance coating for a building with a 50-year service life. There is a coating available that will last 50 years with little maintenance but it has high VOC content. There also is a low-VOC coating available that will provide a LEED credit but has a service life of only three years. Which coating should be chosen? Performance versus environmentally friendly qualities requires a balanced review within LCA calculators if they are to be comprehensive tools. The white paper, “Uncertainty Analysis versus Data Quality Characterization in LCA,” by Greg Norris, Ph.D., founder and director of North Berwick, Maine-based Sylvatica, an international LCA institute, points out that LCA uncertainty in LCI data cannot be neglected nor simply addressed.

Even LCI uncertainty in databases cannot be fully captured because a significant share of this uncertainty arises in practice and is based on the relationship between data and the intended reality being modeled. This complexity is limiting work to specialized LCA practitioners; the tools they use to model data are extremely complex and not practical for a building team.

THE FUTURE IS BRIGHT

Today’s LCA tools’ primary purpose is to develop the LCA of products and not that of entire buildings. The advent of next-generation LCA tools will equip the building team with the ability to assess life-cycle impacts of their building assemblies and ultimately their building structures. Along with other modeling tools, next-generation LCA tools will achieve a whole-building-design view that includes environmental impacts during the design, construction and operational phases of a structure. The challenge for a building team is to balance an informed perspective about current LCA tools with comprehensive product evaluations that include economic, performance, social and environmental impacts, as well as in-use benefits and stewardship requirements.

AVAILABLE LCA TOOLS

Existing life-cycle assessment tools for building teams include the Merrickville, Ontario, Canada-based Athena Sustainable Materials Institute’s EcoCalculator that provides environmental impacts for more than 400 building assemblies. Additionally, the National Institute of Standards and Technology, Gaithersburg, Md., developed BEES, or Building for Environmental and Economic Sustainability, an LCA tool for product-to-product comparisons. Both LCA tools are designed in compliance with ISO 14040, “Standards environmental management—Life cycle assessment—Principles and framework,” which ensures continuity in the LCA process. Other LCA tools are available but require specific training for use.

PAUL R. BERTRAM is director, environment and sustainability, for the North American Insulation Manufacturers Association, Alexandria, Va. He serves as NAIMA’s representative on the High Performance Building Council of the National Institute of Building Sciences, Washington, D.C.; Materials and Resources Technical Advisory Group of the U.S. Green Building Council, Washington; and the Sustainable Building Industries Council, Washington. He can be reached at pbertram@naima.org.

A SUSTAINABLE PRODUCT LEXICON

LEED a program of the Washington, D.C.-based U.S. Green Building Council, is transforming the building industry by providing a framework for defining green buildings. No such definition exists for products and materials. In response to the confusion of what constitutes a sustainable- and/or green-building product and to assist in the evaluation, specification and purchase of these products, the Alexandria, Va.-based Construction Specifications Institute has developed GreenFormat, www.greenformat.com. The tool features a structured self-reporting format for sustainable and environmental product information. ISO 14021 guidelines, which are self-declared environmental claims, are the basis of data reporting in GreenFormat. ASTM E2129, “Standard Practice for Data Collection for Sustainability Assessment of Building Products,” also is referenced as a principal guideline in data reporting.

CSI currently is working with several third-party verifiers for reporting verification but is relying on manufacturers to report accurate data with limited review. GreenFormat is a multi-attribute evaluation tool that provides a searchable database for current, printable information that can assist in comparison and evaluation of materials. It is not a green-product approval, certification, label, reference standard, rating system, testing agency or performance guideline. Instead, it can help building-team members maneuver through the complex maze of sustainable-product attributes, including in-use benefits, company environmental-stewardship efforts and third-party certifications. This information helps balance data gaps and uncertainties of current life-cycle-assessment tools.