Analysis of ES hazards in overfilling protection gauge
Abstract Gauging operations can cause electrostatic ignition in road tankers during filling operations involving flammable liquids. For this reason, gauging from above the liquid surface should not be carried out in a road tanker containing a flammable atmosphere when hazardous conditions are present. Introduction of an overfilling sensor to automatically stop the filling in case of deviation can be a safety measure to prevent overfilling of the road tanker and the generation of a rather big flammable pool. Nevertheless, this situation generates a conflict of interest with the formerly described safety measure of preventing a charged liquid to approach a counter-electrode in presence of a explosive atmosphere. This situation has been assessed in detail by using a simulation program. It was clear that the gauge could lead to an ignition already when the liquid approached the edge of the gauge. A new design was defined to prevent such hazard.