Incidents Triggered by Failures of Level Sensors

Abstract

Level gauging is a basic item of automatic and manual systems for preventing the overfilling of hazardous materials from atmospheric storage tanks. Failures or misuses of these sensors may trigger sever accidents, such as the Buncefield disaster in 2005. Some thirty short reports of minor incidents, near misses and mishaps triggered by failures of the level gauging system, have been found in the documents acquired in recent years during inspections at industrial establishments in the framework of Seveso legislation. They have been investigated, using advanced sematic methods, to understand whether tanks’ operators have implemented the lessons learnt from Buncefield disaster. Among the analyzed documents, in a few cases a serious incident was avoided only by luck, while in other cases the event was very “far” from a real accident, because the resilience of the other safety barriers. The method developed to analyze the collected documents may be useful also to analyze, within the safety management system, the near misses triggered by a sensor failure.