Reasearch On Safety Performance Indicators Evaluation Based On FFTA (Fuzzy Fault Tree Analysis)

Safety performance is the metric used to measure the organizations ability to control therisk of accidents, which indicate the effective of organizations safety efforts. With thedevelopment of safety science and enterprise practice，more approaches to improve safetymanagement level are motivated, including the development of safety culture and the applicationof ethology and psychology into safety field. The two main elements of safety performanceresearch are: build the safety performance indicators, determine the safety evaluation. Asresearch continues, new theory emerges and empirical research feedbacks, there are manyarticles to discuss and improve the performance indicators. So the safety performance indicatorssystem consists of safety culture, risk management and accident management has beenestablished. So research on safety performance indicators is relatively mature, but a number ofquestions remained for the evaluation.The layer evaluation indicators system is a commonly used method to research safetyperformance. Nowaday, research on causal relationship between of safety performanceindicators is the trend. The aim of it is to understand the level of safety performance managementnow. What is the position we should achieve? Where is the gap to the ideal safety performance?According to the causal relationship between of safety performance indicators, not only foundthe direct reason of poor safety performance, but also the potential reason and the way ofinfluence, the result of influence. But the layer evaluation indicators system can not solve theseproblems.Fault Tree Analysis is a skilled events analysis technology in the safety system engineering,it is widely used in the system dependability, is the best method used for causal research. Safetyperformance evaluation system based on the FTA provides an tintegrated planning andcontrolling system by combining safety culture, risk management and accident management.While in the real system, it is hard to quantify. It is may be because that the conception of theevents is vague, the factors that affect the events is complicated and variable, or the eventoccurrence is fuzzy. Meanwhile, the traditional fault tree analysis method can not solve theseproblems.To solve the problems above, and to apply the Fuzzy FTA to the safety performance evalution, and fuzzes the indicators based on fuzzy theory. Through this method, expands thestudies to a great extent, puts forward a FFTA (fuzzy FTA) conceptual, makes safetyperformance evaluation system based on FFTA more operational. The applications includequalitative and quantitative analysis. With the qualitative analysis of FFTA, it obtains theminimal radius set and structure importance which indicate the possible approaches to avoid theaccident. With the quantitative analysis of FFTA, based on triangular fuzzy number, it obtainstop event, the probability importance degree and key importance de which indicate the weaktache of the system and the direction of safety performance.