Quantitative risk assessment of emissions from external floating roof tanks during normal operation and in case of damages using Bayesian Networks

Abstract In this paper, events resulting in an increased or critical emission of volatile organic compounds from external floating roof tanks containing crude and mineral oils with high vapor pressure, e.g. gasoline or naphtha, are investigated. Here normal operations and deviations from normal operations such as tank revision procedures and damages to pipes, seals or deck fittings are included. To record emission-relevant events or damages, a comprehensive literature survey, a Germany-wide survey of companies which use external floating roof tanks and an expert survey were carried out. In addition, the probability of the occurrence of emissions-relevant events was determined and used for risk assessment based on Bayesian networks. This is a well-known method of quantitative risk analysis illustrating and describing causal dependencies. The aim of this work is to show which chains of events can lead to increased or critical emissions of volatile organic compounds. Furthermore, the available data in the literature will be extended by the damage and event rates determined in this work.