News Brief

BEES 4.0 LCA Software Continues Evolution

Building for Environmental and Economic Sustainability, software from the Building and Fire Research Laboratory, National Institute of Standards and Technology (NIST). Free download from or order from the U.S. EPA’s Pollution Prevention Information Clearinghouse, 202-566-0799, For further information, contact Barbara Lippiatt, 301-975-6133,

Continuing its evolution as a user-friendly life-cycle assessment (LCA) tool, version 4.0 of the Building for Environmental and Economic Sustainability (BEES) software was released in May 2007. If you’ve used previous versions, you’ll find version 4.0 quite familiar: the user interface is the same as it has been since version 1. The goal of BEES—making robust LCA results accessible to designers—is formidable. LCA is inherently complex, and most LCA tools cost thousands of dollars and require extensive training to use. With version 4.0, BEES continues to chip away at the obstacles, yet significant challenges remain.

The new release advances the quality and quantity of available data. A total of 230 products are available for analysis and comparison (up from 198 in version 3.0), including 117 generic products and 163 brand-specific products, of which 23 are anonymous. Under the hood, BEES is less error-prone and more transparent than ever before, thanks largely to its use of the publicly available U.S. Life Cycle Inventory database (see


Vol. 12, No. 11) for much of its underlying data. A new weighting option for combining scores from different impact categories was based on aggregated judgments from a BEES stakeholder panel. This panel of LCA experts, manufacturer representatives, and BEES users spent a day using the Analytical Hierarchy Process to assign relative values to each of the impact categories. Reflecting an emerging scientific and public consensus, this panel assigned much more importance to climate change than to the other impact categories.

While BEES continues to improve and address inherent shortcomings, there are still some areas in which it could be accused of overselling the value of its results. At the most basic level, the program’s literature claims that a product with a lower score in BEES has lower environmental impact. While that is likely to be true in most cases, it overlooks the fact that not all environmental impacts of concern are factored into BEES, and some of those that are included may not be a good indicator of actual impacts. For example, as in past versions of BEES, the impact category labeled “habitat alteration” doesn’t consider the effects of harvesting or extracting raw materials, as one might expect, but considers only the landfill space used when disposing of it. Similarly, the “indoor air quality” category is based simply on the total volatile organic compounds (TVOCs) that the product is expected to emit indoors, which doesn’t account for the widely differing impact of different VOCs and omits other compounds that can harm indoor air quality. These shortcomings are explained in the manual but could easily be missed by a casual user.

As in the past, the comprehensive BEES User Manual is a treasure trove of information. Digging into this manual is essential if you want to understand how to interpret the data from BEES, but even if you’re not running the program, you may want to peruse the manual to understand LCA methodology and the makeup of various building materials and products. Thankfully, most of the manual’s contents are also accessible from within the program through its context-sensitive help feature. BEES keeps getting better. That’s a good thing, because with the task it has taken on, there remains a tremendous amount to accomplish with this tool. Use results from BEES with appropriate care, but, if you’re interested in environmental impacts of products, by all means, use BEES.

Published June 7, 2007

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