Offshore users of high voltage explosion protected machines-where are we now?

In the years 1985 to 1991 there were some 4 incidents involving large high voltage explosion protected machines where gas had entered the machine enclosure and ignition of the explosive gas/air mixture had taken place. In addition a machine in 1985 was seen to be sparking on its external covers during start up. These incidents were obviously not acceptable and as well as individual investigations there were a number of safety notices issued by the Department of Energy. In addition some research activities were initiated to investigate the phenomena and the possible causes. As the offshore industry was directly involved in these incidents the operators have taken a number of approaches to deal with existing machines and developed options for selection for new purchases. This paper gives some details of these options and what the offshore operators have in place for their current and future installations