lpg storage spheres risk assessment with fmea and etba methods

introduction: everyone who wants to analyze the safety needs to choose one method among all available ways. this study was carried out to identify energies and barriers in lpg storage spheres in a petrochemical complex using etba method. it also examines the quantitative evaluation of failure modes and their effects as well as evaluation of effect of fmea and comparing the results plus the identification of the advantage and disadvantages of the two methods. materials and methods: using an expert team and by etba’s worksheets, we tried to identify process energies and risks in accordance with mil-std-882 standards. failure modes, different components and the quantified effects of failure as well as their severity score,  occurrence and detectability, and advantage and disadvantage of these methods were assessed. results: in etba study, a total of 30 elements were examined. each of the elements was qualitatively evaluated. our results show that there was 10 unacceptable risks, 7 were undesirable, 8 were acceptable but need ed to be reviewed and 5 acceptable with no need to review. in studying of fmea, 29 potentially failure modes were identified. conclusion: a comprehensive approach for safty assessment such as etba is recommended before any risk analysis for the complicated systems either as primary assessment or  along with any other type of complicated methods.