THE NATURAL STEP AS AN ASSESSMENT TOOL FOR THE BUILT ENVIRONMENT Jennifer R. DuBose, Interface Research Corporation Annie R. Pearce, Georgia Institute of Technology ABSTRACT The Architecture/Engineering/Construction industry has begun to show an increased interest in the concept of sustainability as a way of improving the performance of facilities throughout their life cycle, in terms of indoor and outdoor environment, economics, and other criteria. Decision makers in the A/E/C industry, along with facility owners and users who are interested in increasing the sustainability of their facilities, need a tool with which to evaluate their buildings in terms of the critical variables of sustainability. Because there has been little agreement over the precise composition of sustainability and the essential elements of a sustainable building, different sets of sustainable building indicators have been developed to satisfy the various schools of thought. One of the more promising recent approaches to achieving sustainability is The Natural Step (TNS). Many people seem to like the approach of TNS, since its four system conditions are relatively easy to understand and accept and its tenor is non-judgmental. While the system conditions of TNS provide a useful starting point for evaluation, their application to specific technologies such as buildings is difficult because of the complexity of the technologies and the indeterminate nature of the system conditions. This paper seeks to answer the following question: “How can TNS be applied to built facilities, and what does it mean for how we build buildings?” Using TNS as a framework, we have developed a matrix evaluation tool which categorizes building-related indicators according to the four system conditions. INTRODUCTION Sustainability offers a way of interacting with our world which reconciles the ubiquitous human desire for a high quality of life with the realities of our global context. It calls for unique solutions for improving our welfare that do not come at the cost of degrading the environment or impinging on the well-being of other people. Although there is no general agreement regarding the precise meaning of sustainability beyond respect for the quality of life of future generations, most interpretations of the term “sustainable” refer to the viability of natural resources and ecosystems over time, and to the maintenance of human living standards and economic development [1].