ASTM D7945-2020A Standard Test Method for Dynamic Viscosity and Derived Kinematic Viscosity of Liquids with a Constant Pressure Viscosity meter is a standard method for the measurement of dynamic viscosity and kinematic viscosity of transparent and opaque liquid petroleum products. The method calculates kinematic viscosity by measuring the dynamic viscosity and density of liquids at a set temperature through a constant pressure Viscosity meter. Its application range is wide, including a variety of petroleum liquids, and the measurement results can be used for quality control, product development and performance evaluation. The standard provides an efficient and accurate viscosity measurement means for the petroleum, chemical and other industries to ensure that the flowability and performance of liquid products meet requirements.