ASTM D4399-05 (2023) Standard Test Method for the measurement of conductivity in electrical coating tanks specifies a standard method for evaluating the performance of electrical coating tank liquids by measuring their conductivity. Determination of conductivity helps to control the mass of the electrical coating and ensure the conformity and Stability of the coating. Test equipment, test procedures, and operating conditions are described in detail in the standard to provide accurate and reliable conductivity data to help optimize the electrolysis mass of the coating during production. In addition, measurement conductivity can also reflect changes in the composition of the coating tank liquid, ensuring the efficiency of the electrocoating process and good adhesion of the coating. This method is widely used in electric coating process and painting industry.