(181a) Evaluating Inherently Safer Design with Multi-Attribute Utility Theory

Incorporating inherently safer design (ISD) into a process safety program can benefit a site’s overall process safety program. However, ISD solutions are rarely capable of being implemented without consideration of various tradeoffs associated with other critical operating factors at a plant. Many facilities are therefore left at a crossroad where the safety benefit of an ISD proposal seems ambiguous, undefined, and intangible. Critics have often accused companies of failing to implement ISD solely on the basis of cost, i.e., critics allege that a company is putting profit before safety. Such criticism typically ignores the fact that process safety management decisions tend to involve multiple decision criteria. These criteria can include safety, health, and environmental protection; technological feasibility; commercial feasibility; residual risk; and cost. Multi-attribute decisions are difficult to resolve, but there are tools available to assist the decision maker. One such tool that can be applied to provide insight into the implementation of ISD solutions is multi-attribute utility theory (MAUT). MAUT is a structured approach that evaluates the strengths and weaknesses of competing solutions for a problem with multiple objectives. In this paper, the concept of MAUT will be explained. Then MAUT analysis will be applied to several case studies where investigators have recommended incorporating inherently safer design or technology into a process. Using MAUT analysis the benefit of the proposed design change will be evaluated in a systematic, semi-quantitative methodology that will demonstrate how the tools can help a site understand and characterize the benefits of ISD.