This International Standard specifies two methods of determining the dynamic viscosity of a sample of pitch, which is used as a binder for the manufacture of electrodes required in the electrolytic production of aluminium. The two methods have the same validity for pitches of Newtonian nature and, for these pitches, they are presented as alternative methods. — Method A (Ball displacement method) The method is applicable to pitches of newtonian nature, i.e. containing no additional material. The measurement of the viscosity shall be carried out at a temperature greater than the softening temperature and not greater than 180 °C. The measuring range of the method is 102 to 104 mPa·s. — Method B (Rotation of a cylindrical body method) The method is applicable to the pitches indicated for method A and to pitches for which a non-newtonian nature may be assumed, either because they have been treated at high temperature (presence of mesophase) or due to the necessity of being examined at high temperature (greater than 180 °C). This method allows the non-newtonian nature of a pitch to be characterized. The method is applicable to pitches having a maximum viscosity of 3 × 106 mPa·s.