The evaluation of the safety status of an asset/production plant in the Oil & Gas industry is mainly performed conducting a Quantitative Risk Assessment (QRA). One of the most important factors that affects QRA results is related to the quality of the input data, such as release frequency and ignition probability especially for the cases where flammable substances are involved. For this reason, it is important to have a catalogue of information readily available, reliable and updated. An effort in this sense has been done by the International Association of Oil & Gas Producers. Since 1996, they collect data and issue Risk Assessment Data Directory (RADD). The latest version of these reports (434 series) has been issued in September 2019. In particular, RADD 434-01 focuses on the updated frequencies of releases from process equipment on offshore and onshore installations. Report 434-06 presents instead a reviewed estimation of ignition probabilities based on the UKOOA correlations and suggests the use of alternative ignition models able to reflect the new shift towards sounder and more reliable risk evaluation approaches. One interesting proposed ignition model is called MISOF. This paper aims to present an application of the new updated values of release frequency and MISOF ignition probability model into a QRA study of a typical floating, production, storage and offloading (FPSO) topside. The goal was to capture the main differences in terms of likelihood of final consequences with respect to the results obtained using data from previous methodologies and datasets. The results showed an important reduction in final frequencies for the Jet Fire and unignited dispersion scenarios with a moderate increase for the Flash Fire. The observed reduction in leak frequencies from the new RADD issues outweighed the increase in the ignition probability results coming from the MISOF model.
Industrial activities related to the research, development and production of hydrocarbons are exposed to operational hazards with potentially damaging consequences for human health, environment, and asset. Hydrocarbons are the main process hazards and process leaks are the main initiating events of the escalation to major risk scenarios such as explosions, fires, crude oil and gas spillages from wells, release of contaminants and hazardous emissions. Quantitative risk analyses shall be carried out to have the most comprehensive possible picture of the risk to people associated with the activities. For this purpose, the formal and structured methodology Quantitative Risk Assessment (QRA) is the commonly adopted procedure.
