System safety analysis based on accident mechanism

摘要

There existing the many system safety standards or norms, such as MIL-STD-882, which could be applied in the design and development of engineering systems. However, the system safety analysis in the actual engineering systems, to a great extent, remains to be an "artistic work", which would be usually performed by means of the history experience and the expert intimate knowledge of the systems. As a result of that, it is difficult to ensure the efficiency of the safety analysis. It is a challenging problem how to efficaciously do system safety analysis and successfully achieve expected safety requirements. Aiming at the problem, this paper discusses the concept of the hazard in the field of system safety and the safety accident mechanism and its components. Based on the discussion, it proposes the mehtodology that doing safety analysis should be concentrated on identifying the accident scenarios and their elements. In order to make the idea feasible, a framework for system safety analyis is proposed in detail, which elaborates the functions of the varied types of safety analysis as well as the relationship of them with each other in the course of identifying the whole scenarios and their elements. The safety analysis carried out in a specific engineering system should be guided by the framework so as to ensure the analysis' systematization (embodied with completeness, integration and clearness) and efficacy. In addition, the scenarios identified would be prerequisite to further quantifying safety analysis.