for whole sectors of the economy. I will review some examples of these in the next section, but this section will focus on conventional process LCA, in which there are four main steps: 1. scoping or goal-setting. 2. life-cycle inventory (or LCI): fact-finding to identify and quantify all relevant inputs (e.g. water, energy, and resources), and outputs (including discharges to air, water and land) over a products entire life time. 3. life-cycle impact assessment (or LCIA): analysis of the inputs and outputs described above, often classified in terms of environment, human health, energy use and building operation. 4. improvement analysis: identifying opportunities for improving life-cycle performance. (Young and Vanderburg, 1994; AIA/Demkin, 1998)