“QRA is the art and science of developing and understanding numerical estimates of the risk (i.e., combinations of the expected frequency and consequences of potential accidents) associated with a facility or operation. It uses a set of highly sophisticated, but approximate, tools for acquiring risk understanding. Reference: Arendt, J.S. Lorenzo, D.K. (2000). Evaluating Process Safety in the Chemical Industry – A User’s Guide to Quantitative Risk Analysis. Center for Chemical Process Safety /AIChE.
“Chemical process quantitative risk analysis (CPQRA) is a methodology designed to provide management with a tool to help evaluate overall process safety in the chemical process industry (CPI). Management systems such as engineering codes, checklists and process safety management (PSM) provide layers of protection against accidents. However, the potential for serious incidents cannot be totally eliminated. CPQRA provides a quantitative method to evaluate risk and to identify areas for cost-effective risk reduction.”
Reference: Center for Chemical Process Safety. (2000). Guidelines for Chemical Process Quantitative Risk Analysis (2nd Edition). Center for Chemical Process Safety/AIChE.
Note: It should be stressed that RA in general, despite its intrinsic uncertainties, has a communicative function to lay the ground for rational decision making. Quantification to QRA is needed in the more serious cases.