ATHENA Assembly Evaluation Tool

Common thinking in the green building industry is that Life Cycle Analysis (LCA) is a conceptually preferable method for determining the environmental impacts of materials, rather than relying on singular material properties or attributes, such as recycled content or distances traveled after the point of manufacture. However, the LCA tools that are currently available are not widely utilized by most in the industry, including those designing, constructing, purchasing or occupying buildings. Adding to the lack of LCA use is the failure of popular green building rating systems to fully incorporate LCA.   

Intended to leverage the importance of LCA, the ATHENA Assembly Evaluation Tool was developed for use with the Green Building Initiative’s™ (GBI) Green Globes™ environmental assessment and rating system for commercial buildings with the purpose of providing a simple LCA based framework and tool that could be incorporated within the system.   

The new software tool measures the climate changing potential and other environmental impacts of more than 400 common building assemblies in low- and high-rise categories.  It was created by Morrison Hershfield Consulting Engineers in association with the University of Minnesota's Center for Sustainable Building Research and the Athena Sustainable Materials Institute, and features LCA results generated by the ATHENA® Environmental Impact Estimator software. 

The tool is being reviewed by the GBI American National Standard Institutes (ANSI) technical committee prior to its integration into Green Globes. It will also be made available as a generic version, free of charge, to the entire sustainable construction community, and both versions include the following elements: 

• A list of common building assemblies for office, commercial or industrial buildings. These assemblies are broken into categories based on broad system type (exterior walls, interior walls, window systems, beams, columns, intermediate floors, and exterior roofs), and by low- and high-rise buildings.
  
• The ATHENA Environmental Impact Estimator software was used to develop LCA information on each building assembly. LCA results were developed for the following indicators: primary energy (fossil fuel depletion), global warming potential, air and water pollution indices, and other resource use weighted to reflect the effects of extraction.
  
• Points are awarded for a singular assembly by comparing its performance across each indicator measure to all other assemblies within the functional equivalence category (ex. Exterior walls for low-rise buildings). Assemblies with better than average performance across an indicator measure receive points (on a sliding scale), and the overall points for a particular assembly represent the sum of the points for each indicator category.
• A Microsoft Excel based tool was developed to easily convey the information. The tool is currently broken into two files, one for high-rise buildings and another for low-rise buildings, with the structure of these two files being identical and only the assembly definitions and data changing. Each tool is an Excel workbook containing several worksheets, and there is one worksheet for each of the following assembly categories; intermediate floors, interior walls, windows, exterior walls, roofs, and columns and beams. Within each page is a list of all possible assemblies within the category. 

The tool allows an unbiased comparison of material assemblies across a set of environmental indicator categories. The tool will be continually updated as new building product data or new assemblies emerge in the market. In addition, an alternative compliance path involving whole building LCA may be explored and incorporated into Green Globes in the future.