Analyzing Hazards in Process Systems Using Multilevel Flow Modelling: Challenges and Opportunities

Process safety is complex since the production process is a unified system comprised of mass, energy, and information, in which the effects of failures are interconnected and transmitted, leading to a chain reaction throughout the process. Multilevel Flow Modeling, as a methodology in functional modeling, performs well in supporting situation
awareness and fault diagnosis, through modeling process systems and reasoning about hazard scenarios. Applying Multilevel Flow Modeling to hazard identification and deviation analysis and developing a computer-aided HAZOP tool can potentially improve the efficiency of the conventional HAZOP study. Multilevel Flow Modeling is not sufficient for computer-aided cause and consequence analysis, due to the fact that individual deviations are examined independently in terms of their causes and effects. Because of this limitation, risk can be underestimated because of a lack of consideration for the ”duplicate effect” of deviations, resulting in an insufficient barrier configuration. By reviewing the methods of risk assessment and the development of Multilevel Flow Modeling in process safety, this article discusses the opportunities and challenges that can be encountered when combining hazard analysis with ”duplicate effect” and the representation and analysis of barriers in Multilevel Flow Modeling. The authors aim to develop an approach to enhance the hazard analysis and barrier representation through the extension of Multilevel Flow Modeling, which will facilitate the identification and optimization of safeguards.