Abstract

Greenhouse gases and energy extraction, production and consumption contribute to polluting the environment, and have led to climate change and global warming, now ranked as one of the top priorities on the United Nations' environment agenda (Montreal & Kyoto protocols). In the United States and Canada, the building sector represents the third-largest domain of total energy consumption, after the industrial and transportation sectors. In Canada and the United States alone, close to 80 million students, teachers and staff spend at least eight hours a day in schools. There is a growing demand to construct sustainable schools designed to provide more healthy, comfortable and productive learning environments as well as to reduce energy consumption and building costs. The research presented here details the development of a Selection Framework that enables school boards to select sustainable and cost-effective structure and envelope types for new school buildings. The selection is performed based on an evaluation of the LEED (Leadership in Energy & Environmental Design) rating system and life-cycle costing techniques for typical structure and envelope-type alternatives. Fourteen different structure and envelope types are investigated, covering steel, concrete, and wood structures, in various combinations covering both conventional and sustainable options. A Sustainability Assessment Model is developed to measure the sustainability performance of conventional or "Non-green" alternatives, based on the evaluation of certain LEED categories such as energy consumption, recyclability and reuse of material, along with incorporating the LCA (Life Cycle Assessment) technique. Furthermore, Life Cycle Costs Forecasting Models are developed by applying Monte Carlo simulation to determine the cost effectiveness or the economic viability for fourteen green and non-green school structure alternatives. Comparisons between these alternatives are performed using various deterministic and stochastic approaches in accordance with confidence levels, and risk assessment using the Efficient Frontier technique. The selection criteria was evaluated and weighted by experts' opinions. Their evaluation indicates that running costs represent the most significant criterion, followed by initial costs and then sustainability. The selection of alternatives based on a deterministic approach was subjected to high risk, and the selection is also enhanced by applying the Efficient Frontier technique (risk assessment). It is found that, if the selection is based on only one life cycle stage, it would lead to a decision that would not be the best for the long term. Hence, whole life cycle stages should be considered in the selection. It is seen that this research provides a method that can assist governments and decision makers in minimizing their overall expenditures on public buildings and to provide the best possible structural/envelope system, while simultaneously reducing greenhouse gas emissions and minimizing the environmental impact associated with public sector buildings.