What are Precautionary measures to minimize accumulation of static charges?

Conductors introduced

During the loading of any cargo which may give rise to flammable vapours no earth conducting probe and no unearthed conductor capable of gathering charge from the liquid should be allowed inside the tank during loading. An example of this would be a metal weight on the end of a metal tape or a tin can or metal sampling can suspended from an insulated rope and floating on the surface of incoming cargo i.e. ullaging & sampling. The possibility of ignition by static tanks and compartment’s which have been discharged, but are not gas free arises when conductor is suspended in a tank and steam is also present. hence no tank washing machine or other conductor whether earthed or unearthed, should be permitted in a tank which has steam injected unless of the direct fixed type.