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04/01/2009

EnvironDesign Notebook: Indoor Air Quality: A Critical Part of the Life-Cycle Equation

As testing requirements have become more sophisticated, bringing IAQ into the LCA equation needs to be high on the agenda for future LEED enhancements.

By Bruce Maine

 

As Roy Scheider stumbles into the cabin of the Orca after coming face to face with the shark off the boat’s stern, he apprehensively exclaims to Robert Shaw, “We’re going to need a bigger boat!”

I often think of this scene from the movie “Jaws” when I’m confronted by the ever-increasing number of green building product initiatives; at times it seems these programs have experienced a growth rate that has outpaced our capacity to comprehend them. This is especially true with regard to programs that intend to reward exemplary performance for superior indoor air quality (IAQ) attributes.

When the LEED® Green Building Rating System™ was first crafted in 2000, the only IAQ requirements for building products concerned adhesives, sealants and paints. That list has subsequently been expanded to include a much greater variety of products such as furniture, hard surface flooring, carpeting, ceiling systems, insulation, and wallboard.

Now that LEED 2009 looms on the horizon, one must assess the impact of IAQ testing in the new paradigm. LEED 2009 redistributes the weight of available points relative to each credit’s ability to potentially mitigate a building’s environmental impact. By using the areas of concern identified by EPA’s Tools for the Reduction and Assessment of Chemicals and other Impacts (TRACI), the U.S. Green Building Council (USGBC) is attempting to define in LEED 2009 the concept of Life Cycle Assessment (LCA). Climate change has been identified as the most important area of concern in LEED 2009, and thus receives the most weight: 32 percent of credits in LEED 2009 address energy efficiency as compared to 24 percent in LEED 2.2.

As a result, credits related to materials and their impact on indoor environmental quality will play a much smaller role, largely because TRACI categories were originally designed to evaluate products based on their impact on the natural environment. TRACI provides relatively limited information about the impact of a product on its users or on the occupants of the building in which it is used. In fact, TRACI has no categories for indoor environmental quality or productivity since IAQ accounts for only 3 percent of TRACI impacts.

Hal Levin, a noted IAQ authority, takes issue with such a methodology and suggests that “various approaches to developing an IAQ profile for a product can be integrated into Life Cycle Assessments.” In short, he argues that an evaluation of IAQ characteristics should be measured with the same Cradle to Cradle litmus used to identify any product’s environmental footprint.

Levin advocates for a “Building Ecology” approach that would consider human impacts in the production of materials and their incorporation into buildings, as well as the impact on building occupants through, among other things, IAQ effects.

“If building materials are selected that have low impact on the external environment, but are either unhealthy or unpleasant for building occupants, these materials are impractical and unacceptable, and they will not be used in buildings. Therefore, indoor air quality must be assessed and the results must be integrated into LCAs on building materials,” he says. Eco-labeling programs, life-cycle studies and environmental performance declarations, he notes, all rely on the careful selection of life-cycle impact categories, and the development of accurate methods for calculating results in each of these categories. For product categories that create IAQ impacts or dermal toxicity issues which might be encountered by exposure to chemicals such as phthalates, PBDE and other persistent chemical exposures, Levin proposes that a separate impact category must be established. Unfortunately, he adds, IAQ is not often used as a LCA impact category.

The one LCA tool where IAQ is included is the BEES (Building for Environmental and Economic Sustainability) software that integrates standard approaches for selecting cost-effective, environmentally preferable building products. Version 4.0 of the Windows-based decision support software, aimed at designers, builders and product manufacturers, includes actual environmental and economic performance data for more than 230 building products across a range of functional applications. BEES measures the environmental performance of building products using the environmental LCA approach specified in International Organization for Standardization (ISO) 14040 standards.

All stages in the life of a product are analyzed: raw material acquisition, manufacture, transportation, installation, use, and waste management. Economic performance is measured using the ASTM International standard life-cycle cost method (E 917), which covers the costs of initial investment, replacement, operation, maintenance and repair, and disposal. Environmental and economic performance attributes are combined into an overall performance measure using the ASTM standard for multiattribute decision analysis (E 1765). BEES uses the Society of Environmental Toxicology and Chemistry (SETAC) method of classification and characterization. These six Life Cycle Assessment impact categories used by BEES are:

  • global warming potential
  • acidification
  • eutrophication potential
  • natural resource depletion
  • solid waste
  • indoor air quality

Synthesizing these six impact category performance measures involves combining apples and oranges. Global warming potential is expressed in CO2 equivalents; acidification in hydrogen equivalents; nitrification in phosphate equivalents; natural resource depletion as a factor reflecting remaining years of use and reserve size; solid waste in volume to landfill; and air quality as a dimensionless score. To compensate, BEES uses an equation from an ASTM standard that weights the impact category by its relative importance to overall performance. In this scenario, the relative importance of IAQ ranges from 27 percent to 12 percent.

References:

Integrating Indoor Air Quality Considerations into Materials Life Cycle Assessment, June 30, 2008; Hal Levin

The BEES Model for Selecting Environmentally and Economically Balanced Building Materials, 1998; Barbara Lippiatt

The USGBC has many issues to confront with respect to framing a new and inclusive approach to IAQ issues. When we just had to worry about a volatile organic compound or two, the reference standards seemed appropriate. But when testing protocols grew in complexity, so did our understanding of them. The debate between competing interests was sometimes contentious and when California’s Section 01350 was introduced into the mix, the stakes were significantly raised as it called for concentrations of any chemical listed as a probable or known carcinogen or as a reproductive toxicant to be included in the testing protocol. Clearly, IAQ testing requirements have becoming increasingly sophisticated and will be more so now that LCA must be considered.

This is not to suggest that the USGBC is minimizing the value of IAQ in the LEED process; in fact, the number of specific products evaluated for exemplary IAQ performance continues to expand. But the issue for future LEED versions is whether a strategy can be established where a testing protocol can include those elements that define how products identified for exemplary IAQ characteristics are equally recognized for their LCA contribution. Bringing IAQ into the LCA equation must be high on the agenda for future LEED enhancements.

A pioneer in the field of sustainable building materials, Bruce Maine has been on the forefront of the movement to evaluate the environmental and economic performance of building materials from numerous perspectives. Serving multiple roles as specifier, advocate and educator, Maine uses both his knowledge and his commitment to produce policies, tools, and resources for his clients and colleagues, including the HDR Sustainable Products Database. He can be contacted at bruce.maine@hdrinc.com.

 

 
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