ENVIRONMENTAL FOOTPRINTS AN ENVIRONMENTAL ASSESSMENT TOOL

Abstract

An environmental footprint (EF) methodology was devised to fulfill a need to evaluate decisions made in the building industry. The need for such a framework was recognized when builders began framing homes with steel, rather than with wood - the traditional material. Deciding on a material of choice should embrace environmental criteria, rather than be based solely on economic and product performance criteria, which has been a trend in the past. The EF framework stems from the concept of ecological footprints, which is an assessment tool that calculates the amount of land that a community requires indefinately to maintain a set standard of living for a set population. In essence, the level of environmental "unsustainability" is measured by this tool. Environmental footprinting is an extension of ecological footprints as it considers impacts on the land, air and water, in the context of an industrial application. Again, it is used as a sustainability yardstick and is extremely valuable for comparative as well as improvement identification purposes. Furthermore, EFs fulfil in part the third stage of Life Cycle Assessment (LCA), that of impact assessment. To illustrate the usefulness of the devised framework, EFs were calculated for four wall unit designs framed with steel and wood. The results showed that the wood wall unit designs had larger land footprints, but smaller air and water footprints than did the steel designs. However, the magnitudes of the air and water impacts were significantly larger than for the calculated land impacts. Although the actual impact values obtained from EF calculations are relevant, comparing the relative differences between two footprints is more useful in decision making situations. The results from the wall unit application were useful for demonstrating the EF framework, however, it was realized that EFs need to be utilized in more holistic applications, rather than in isolated applications.