Método sistemático de identificação de componentes e grupos de corte (cut sets) críticos em árvores de falha

Abstract

Systems design is guided by safety standards, which are established and accepted by society. In order to achieve an industry certification, these standards must be followed and, lately, audited by specific organizations that will verify if they comply with the safety goals. This is the case of the following industries: nuclear, aerospace, military, rail. As relevant as design systems with satisfactory safety levels is the monitoring of the safety performance throughout operational life. Industry standards establish safety levels to be monitored along the product life in order to identify risks higher than those of the design certification and to provide necessary system modifications to return it to initial safety levels. Design evolution reveals that current systems present an increased complexity and a higher number of components. It is not possible to manage the safety levels monitoring every item of a system. This monograph presents a systematic method to identify critical components and cut sets from the fault trees elaborated during the development phase of a system in order to continuously monitor and manage risk. This method of identification of critical fault tree components and cut sets is executed using analyzes such as fault tree, importance measures of components and events, Pareto concept, life data analysis, MTBF and MTBUR calculation. The method applied to a set of 6 fault trees, which contain a total of 243 events, selected 14,81% of the most critical events in order to be monitored during the operational life.