Abstract:

The double prevention mechanism was a widely used risk control system in hazardous chemical fields in China. However, the theoretical framework at underlying and operational levels was missing. Especially, there was a lack of RCA results to guide double prevention. Therefore, VPSB model was proposed by integrating primary-secondary barrier theory and ECF analysis technology. Furthermore, ECF as a typical RCA method represented the causal of a catastrophic event composed of specific primary-secondary barrier failure modes, providing a visualized diagram for the VPSB model. The model was used to identify hazards and RCA for a typical accident scenario in the Texas explosion of British Petroleum(BP) company. Moreover, the failure modes of double prevention related to management measures were investigated. The comparisons of investigation results between the U.S. Chemical Safety Board (CSB) and BP indicated that people's unsafe actions were taken as the direct cause to carry out in-depth cause analysis. Moreover, the focus was human management, and the failure of the safety supervisors and irregular operations of the operators were macroscopically summarized as the root causes. However, the VPSB model focused on near-miss and the process of major accident hazards, and detailed sub-barrier failure modes were used to highlight the fundamental problems of management systems. Specifically, mechanical integrity management had the largest number of problems because management measures were not conducted as required. This study can provide rectification directions and operability recommendations for enterprises to optimize the relevant work content of the double prevention mechanism.

Key words: visualized primary/secondary barriers (VPSB) model, chemical installation, root cause analysis(RCA), double prevention mechanism, event and cause factor (ECF) analysis, accident scenario