RR716 - A review of Layers of Protection Analysis (LOPA) analyses of overfill of fuel storage tanks

In response to the Buncefield incident, the Major Incident Investigation Board (MIIB) made recommendations to improve safety in the design and operation of fuel storage sites. Two of these recommendations were that loss of primary containment (tank overfill) should be prevented by a high integrity system, and that industry should agree to undertake a systematic assessment of safety integrity levels using commonly agreed methods.

The Buncefield Standards Task Group (BSTG), consisting of representatives from industry and the control of major accident hazards (COMAH) Competent Authority, also stated in its final report, Paragraph 16, "Before protective systems are installed there is a need to determine the appropriate level of integrity that such systems are expected to achieve." The BSTG report suggests a layer of protection analysis (LOPA) study be used to provide a more consistent approach to safety integrity level (SIL) determination.

Therefore, in response to the MIIB and BSTG recommendations this study aimed to identify common trends and instances of good practice and areas requiring discussion / improvement in the way in which LOPA studies were carried out by operators of sites that bulk store fuels such as petrol.

This study is part of ongoing work to stimulate discussion between concerned parties with the aim of contributing to the development of improved guidance.

This report and the work it describes were funded by the Health and Safety Executive (HSE). Its contents, including any opinions and/or conclusions expressed, are those of the authors alone and do not necessarily reflect HSE policy.

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Updated 2021-04-23