The Use of Risk Index Systems to Evaluate Risk

Abstract

Risk indexing is a useful and powerful tool that can provide valuable information on the risks associated with chemicals and chemical processes. As defined here, risk indexing is the process of modeling and scoring chemical hazard and exposure parameters to produce a rapid and simple estimate of relative risk. The principles of risk indexing can be applied to a variety of risk assessment projects to set priorities and help manage resources. Within the framework of basic risk assessment principles, however, different levels of risk index depth can be developed. A simple risk index can be considered to be at one end of a continuous risk analysis spectrum, where hazard and exposure are quickly estimated through the use of simple models. A full quantitative risk analysis would be at the other end of this risk analysis spectrum, where hazard and exposure are tested, measured, and assessed as rigorously as possible. Choosing the depth of the risk analysis is a critical decision that depends on such factors as the time and resource commitment to the project, the number of materials or processes to be analyzed, and the desired endpoint of the risk index analysis. This report demonstrates three levels of risk index analysis for a hypothetical ammonia storage system and analyzes the relative merits of each. The analysis and discussion offer guidance for appropriately selecting the depth of risk index analysis based on the desired risk analysis endpoint.