HG/T 4443-2012 "Spinning & weaving dyeing and finishing aids, Determination of viscosity" standard specifies a detailed method for determining the viscosity of Spinning & weaving dyeing and finishing aids using the rotational viscometer method. This standard applies to Spinning & weaving dyeing and finishing aids having the characteristics of newtonian fluid or approximately newtonian fluid. During the determination, the resistance generated by the internal relative motion of the fluid is measured by a rotational viscometer to reflect its dynamic viscosity. The standard details the requirements for instruments and equipment, including the use of rotational viscometers, thermostatic baths and thermometers. The assay steps include preparing the specimen, setting the thermostatic conditions, selecting the appropriate rotor and Rotation speed for the assay, and requiring three measurements per specimen to ensure the accuracy of the results.