A Robust Sustainability Metric Using Possibility Distributions

One significant challenge in developing life cycle performance models for buildings is how to define "performance". While the classical definition of performance of a building is based on safety and serviceability criteria, the definition for high-performance buildings for sustainable developments is based on additional criteria mostly related to energy and environment such as improved energy, economic, and environmental performance. The guidelines for defining these criteria include imprecise, or linguistic measures (e.g., "high", "medium", or "low"). These types of measures would lead to soft/fuzzy evaluations that cannot be added using simple mathematical or probabilistic models. Using the theory of possibility, a new robust metric for evaluating sustainability in buildings is being developed. This new metric is necessary because existing evaluation systems such as LEED and Green Globes lack the ability to gain partial credit and overlook the existence of several types of uncertainties associated with the evaluation process. A case study, presented here, demonstrates how the new metric integrates definitions across existing sustainability measures using possibility distribution.