Quantitative risk analysis in the chemical process industry

Abstract Quantitative Risk Analysis (QRA) is a tool that is being used increasingly in the chemical process industry (CPI) to help prevent rare but potentially catastrophic events. The QRA methodology includes: 1. (1) establishing QRA priorities, 2. (2) identifying accident scenarios, 3. (3) quantifying the frequency of each scenario, 4. (4) quantifying the consequences of each scenario and 5. (5) quantifying total risk. A wide variety of factors contributed to the rather large uncertainty of QRA results. The results of a QRA can be expressed in terms of absolute risk which can be compared to established levels of unacceptability. The result can also be expressed in terms of relative risk, indicating the effect on risk of various design options. However, the most important result of QRA is the operational insights revealed to the analysts which lead to risk reduction and understanding of the sources of residual risk. This paper describes the QRA method as it is used in the CPI.