Ignition source static electricity: Incident investigation

Static electricity still represents a frequent ignition source when flammable liquids or combustible powders are handled and processed in industry. The present report deals with the investigation of an incident which occurred during splash filling 200 liter metal drums with isopropyl acetate. Although from the point of view of static electricity isopropyl acetate belongs to the group of liquids with high conductivity, the experimentally in situ determined charge to mass ratios and charging currents are extremely high compared to low conductivity liquids such as hydrocarbon fuels. The ignition of the isopropyl acetate vapors can also be explained if the metal drum was properly earthed. Since the drum had a highly insulating coating with a breakdown voltage of 1.1-1.9 kV the explosive atmosphere could also have been ignited by a discharge from the highly charge isolated liquid. (C) 2009 Elsevier B.V. All rights reserved.