This International Standard specifies a method for the direct determination of water in petroleum products boiling below 390 °C. It covers the mass fraction range 0,003 % (m/m) to 0,100%(m/m). It is not applicable to products containing ketones or to residual fuel oils. This International Standard may be applicable to lubricating base oils. However, the precision has not been established for these materials. The precision given in clause 12 is based upon data obtained using dual-cell, dual-electrolyte systems.