Best Practice and Common Practice in Risk Assessment

When dealing with risk reduction, a number of risk assessment methods are currently used to design and implement appropriate safeguarding. At present time, it is crucial for the industry to operate plants at minimum risk levels and optimum capacity. Determining generally accepted risk tolerability criteria is paramount in order to avoid both over- and under-engineering. This study has been conducted in order to investigate thresholds of tolerability that have been applied in real LOPA (Layer of Protection Analysis) studies. Risk matrix studies have also been analyzed for comparison. The differences and commonalities in the projects have been studied and average results have been consolidated into a reference Risk Matrix. The general Risk Matrix thus obtained represents current industry common practice with respect to guaranteeing personal safety. This tool can be used as a practical reference in risk assessment. For small and middle end-users and for independent consultants, the tool can provide a valid starting point for risk reduction considerations in new projects. Since the whole Functional Safety framework in a plant rests on the applied risk tolerability criteria, the author considers this study relevant, and would like to use this opportunity to share our findings beyond the national borders.This paper is developed with written permission from the original authors, based on the paper of the SIL Platform.