This standard provides the rules to be followed for the determination of the water content in insulating mineral oils as well as in oil-impregnated paper and board. Section one of this standard describes the determination of water in insulating oils, both new and in service, in the concentration range between 2 mg/kg and 100 mg/kg. The precision values indicated in chapter 12 are applicable only to samples of new oils whose viscosity at 40 °C is less than 20 mm2/s.