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Normalization of process safety lagging metrics



This article explores new process safety metrics for measuring process safety performance in the chemical processing industry. While Process Safety Management enables an operation to optimize their process safety programs and organizational risks, there is an emerging need to evaluate process safety implementation across an organization through measurement of key indicators. Lagging metrics utilize process safety incidents as the numerator and divide it by an appropriate process-related denominator or “normalization factor.” Currently, work hours is used extensively as a normalization factor to evaluate safety performance in the process industries. However, this lagging metric does not directly reflect process safety information and may not accurately reflect the safety performance of the process. Modified denominators are explored in this study and compared with the existing time-based denominator to validate the effectiveness and applicability of the new metrics. Each proposed normalization factor was validated using available industry data. A statistical unitization method has been used to convert incident rates of different ranges for the convenience of comparison. Results show that some proposed process-related metrics have potential as alternatives, used along with the time-based metric, to evaluate process safety performance within organizations. © 2013 American Institute of Chemical Engineers Process Saf Prog 32: 337–345, 2013