From building green to monitoring carbon footprints, sustainability has become part of doing business for many corporations. These companies no longer look at the growing green trend as an obstacle but as an opportunity to supplement their legacy.

The effect on the corporate world is evident. But less obvious is the fact that corporate culture, with its inherent focus on performance, also has begun to influence the sustainability movement in a positive way.

The shift is especially pronounced in the context of green-building rating systems, which in the past have been more prescriptive than performance-based. As an example, some rating systems give credit for materials produced within 500 miles of where the structure is being built. This makes sense on an intuitive level because less energy is required to transport the materials.

But there are a tremendous number of factors that influence whether a locally produced material actually is better for the environment. These factors include the source of the material's components, type of manufacturing process, and mode of transportation. Using locally produced materials could add to or detract from a building's sustainability.

Those who want to know for sure, including many of those involved in the development and evolution of green-building rating systems, are placing an increasing emphasis on life-cycle assessment, or LCA. LCA is important to sustainable design because it facilitates impartial comparisons of materials, assemblies, and entire buildings. It considers materials during the course of their entire lives, from resource extraction through recycling, reuse, or disposal. LCA also takes into account a range of environmental impact indicators, such as embodied energy and global warming potential.

Instead of rewarding materials or products for specific attributes that we assume have environmental benefits, rating systems that incorporate LCA put the emphasis where it should be—on building performance. This gives designers the flexibility to choose how to achieve their environmental goals.

Accessible technology

Although many recognize LCA as one of the best ways to assess building sustainability, the challenge has been the perception that LCA is too complex and time-consuming to be used by the mainstream design community.

To help make it more accessible, the Athena Sustainable Materials Institute, Merrickville, Ontario, Canada, recently released a new spreadsheet tool, the Athena EcoCalculator for Assemblies. It is available for free to architects, engineers, and others who want to evaluate building designs based on a more complete understanding of total environmental impact.

Developed by the Athena Sustainable Materials Institute in partnership with the University of Minnesota, Minneapolis, and Morrison Hershfield Consulting Engineers, Toronto, the Eco-Calculator originally was commissioned by the Portland, Ore.-based Green Building Initiative (GBI) for use with its Green Globes environmental assessment and rating system for commercial buildings. But because of its value as an indicator of potential climate change impact, GBI also supported creating a generic version that could be used by the entire sustainable design community.

The EcoCalculator provides instant LCA results for hundreds of common building assemblies, including exterior walls, roofs, intermediate floors, interior walls, windows, and columns and beams. The information embedded in the tool is based on detailed assessments completed with its parent software, the Athena Impact Estimator for Buildings. This, in turn, uses Athena Sustainable Materials Institute's own datasets along with data from the U.S. Life Cycle Inventory Database established by the National Renewable Energy Laboratory, Golden, Colo.