Off shore units eh? Might that include oil and gas rigs as found in the North Sea near to where I live? They are lit up at night like candles. So we have bad weather, storms, salt water, snow, flammable gasses and flammable oil.
Sometimes there can be problems even if the correct equipment is used.
"In a recent incident on an offshore installation, there was an explosion in an open drains tank containing oily water. The tank contained an electric heater which was Ex certified. However, the sheath on the electric heating element had corroded, exposing the conductor. Although the incident is still being investigated, it is thought that this fault led to ignition of flammable material in the tank."
9. A small number of violent explosions of Ex luminaires have occurred offshore and it is suspected that hydrogen generated in the luminaires was the source of the flammable mixture rather than hydrocarbons released from the process plant. Excessive ingress of sea water can result in hydrogen generation by electrolysis. Tests carried out by the Health and Safety Laboratory (HSL) have demonstrated that electrolysis of sea water is possible, but is highly dependent on luminaire component geometry and ballast design. Hydrogen generation by electrolysis is equally possible with bi-pin or mono-pin designs.
