ISO 2909:2002描述了两种根据石油产品和相关材料（如润滑油）在40℃和100℃下的运动粘度计算其粘度指数（VI）的程序。 程序A适用于粘度指数高达100（含100）的石油产品。 程序B适用于粘度指数为100或更大的石油产品。 ISO 2909:2002不适用于100℃下运动粘度小于2.0 mm2/s的石油产品。它适用于100℃下运动粘度在2mm2/s至70mm2/s之间的石油产品。提供了用于计算在100℃下运动粘度高于70mm2/s的石油产品的粘度指数的方程。

ISO 2909:2002 describes two procedures for calculating the viscosity index (VI) of petroleum products and related materials, such as lubricating oils, from their kinematic viscosities at 40 °C and 100 °C. Procedure A is applicable to petroleum products of viscosity index up to and including 100. Procedure B is applicable to petroleum products of viscosity index 100 or greater. ISO 2909:2002 does not apply to petroleum products with kinematic viscosities less than 2,0 mm²/s at 100 °C. It applies to petroleum products with kinematic viscosities between 2 mm²/s and 70 mm²/s at 100 °C. Equations are provided for calculating the viscosity index of petroleum products having kinematic viscosities above 70 mm²/s at 100 °C.