Tank filling operations

One of the issues identified in the sample review of LOPAs in HSE s research report RR716 was that the identification of initiating events was not comprehensive and therefore that the frequency of demands on protection layers may have been underestimated. It is important that the process for identifying initiating events is comprehensive and that it is carried out with the involvement of those who have to perform the tank-filling operation. 

Care needs to be taken in using this conditional modifier that it is truly independent of the initiating event, any enabling event or condition, or any protection layer. If normal tank-filling operations require the presence of an operator, or if part of the emergency response to an overflow event requires operators to investigate the incident, this conditional modifier will not be independent. 

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