Fault tree analysis of the hottest fire and explos

2022-09-22
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Fire and explosion fault tree analysis (oil depot static electricity) - fault tree (2)

1 fault tree basic level and enterprise response analysis method

fault tree analysis method (FTA) is a graphic deduction method, which is a directed logic tree analysis method to describe the accident from the result to the cause. This tree is a process of logical analysis, which follows the principle of logical deductive analysis (that is, the principle of analysis from result to cause). Take the event that the system does not want to appear as the top event of the fault tree, and use the logic "and" or "gate to analyze all the possible direct causes of the top event and the logical relationship between them from top to bottom, so as to gradually deepen until the basic cause of the accident is found, that is, the basic event of the fault tree

2 basic procedure of fault tree analysis

basic procedure of FTA method: familiar with the system - investigate accidents - determine top events - determine objectives - investigate cause events - prepare fault tree - qualitative analysis - quantitative analysis - safety evaluation. The process of fault tree analysis can be roughly divided into 9 steps. Steps 1-5 are the preparation stage of analysis and the basis of analysis, which belongs to traditional safety management; Step 6 mapping is the key to analyze whether it is correct or not; Step 7 qualitative analysis is the core of the analysis; Step 8 quantitative analysis is the direction of analysis, that is, to use data to indicate whether it is safe or not; Step 9 safety evaluation is the purpose

3 establishment of fault tree of electrostatic fire and explosion in oil depot

the establishment process of fault tree of oil depot fire and explosion caused by electrostatic sparks in oil depot is shown in Figure 1

Figure 1 oil depot electrostatic fire and explosion accident tree

(1) determine the top event - "oil depot electrostatic fire and explosion" (first floor)

(2) investigate the direct cause of the explosion, the nature and logical relationship of the event. Direct cause events: "electrostatic spark" and "oil and gas reach combustible concentration". These two events should not only occur at the same time, but also when "oil and gas reach the explosion limit", the explosion event will occur. Therefore, use the "condition and" door connection (second floor) to preheat for 10 minutes

(3) investigate the direct cause, nature and logical relationship of "electrostatic spark". Direct cause events: "oil depot electrostatic discharge" and "human electrostatic discharge". As long as one of these two events occurs, the "electrostatic spark" event will occur. Therefore, use "or" door to connect (three floors)

(4) investigate the direct cause events of "oil and gas reaching combustible concentration", the nature and logical relationship of the events, and the direct cause events: "oil and gas exist" and "poor ventilation in the reservoir area". "Oil and gas exist" is a functional event under normal conditions, so this event is symbolized by a room. "Poor ventilation in the reservoir area" is a basic event. These two events only occur at the same time, and the event of "oil and gas reaching combustible concentration" will occur, so the "and" door is used to connect (three floors)

(5) investigate the direct cause event of "electrostatic discharge in oil depot" and its nature and logical relationship. Direct cause events: "electrostatic accumulation" and "poor grounding". These two events must occur at the same time before electrostatic discharge can occur, so the "and" door is used to connect (four floors)

(6) investigate the direct cause of "human electrostatic discharge", the precautions for the use of the testing machine, the nature and logical relationship of the event. Direct cause events: "friction between chemical fiber and human body" and "proximity to conductor during operation". Similarly, these two events must occur at the same time before electrostatic discharge can occur, so it is connected with the "and" door (four floors)

(7) investigate the direct cause, nature and logical relationship of "electrostatic accumulation". Direct the events during the original "1025": "high oil flow rate", "rough inner wall of the pipeline", "high-speed pumping", "oil impact on metal containers", "splashed oil friction with air", "metal floating objects on the oil surface" and "measurement operation error". As long as one of these events occurs, there will be "static electricity accumulation". Therefore, use "or" door to connect (five floors)

(8) investigate the direct cause event, the nature of the event and the logical relationship of "poor grounding". Direct cause events: "no anti-static grounding device is set", "the grounding resistance does not meet the requirements" and "the grounding wire is damaged". As long as one of these three events occurs, "poor grounding" will occur. Therefore, use "or" door to connect (five floors)

(9) investigate the direct cause event, the nature of the event and the logical relationship of the "measurement operation error". Direct cause events: "the appliance does not meet the standard" and "insufficient standing time". If one of these two events occurs, "measurement operation error" will occur. Therefore, the "or" door is used for connection (six floors)

Zheng Xianbin, Chen Guoming

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