1. Scope
1.1 This practice specifies the procedures for calculating the viscosity index of petroleum products, such as lubricating oils, and related materials from their kinematic viscosities at 40 and 100°C.
1.1.1 Procedure A - For petroleum products of viscosity index up to and including 100.
1.1.2 Procedure B - For petroleum products of which the viscosity index is 100 or greater.
1.2 Table 1 given in this practice applies to petroleum products with kinematic viscosities between 2 and 70 mm 2/s (cSt) at 100°C.4 Equations are provided for calculating viscosity index for petroleum products having kinematic viscosities above 70 mm2/s (cSt) at 100°C.
1.3 The kinematic viscosity values are determined with reference to a value of 1.0038 mm2/s (cSt) at 20.00°C for distilled water. The determination of the kinematic viscosity of a petroleum product shall be carried out in accordance with Test Methods D445, IP 71, ISO 3104, or ISO 2909.
1.4 The values stated in SI units are to be regarded as the standard.
2. Referenced Documents
2.1 ASTM Standards:
D341 Viscosity-Temperature Charts for Liquid Petroleum Products
D445 Test Method for Kinematic Viscosity of Transparent and Opaque Liquids (and the Calculation of Dynamic Viscosity)
D1695 Terminology of Cellulose and Cellulose Derivatives
2.2 ISO Standards:
ISO 2909 Petroleum products - Calculation of Viscosity Index from kinematic viscosity
ISO 3104 Petroleum products - Transparent and opaque liquids - Determination of kinematic viscosity and calculation of dynamic viscosity
2.3 IP Document:
IP 71
3. Terminology
3.1 Definitions of Terms Specific to This Standard:
3.1.1 viscosity index, n-an arbitrary number used to characterize the variation of the kinematic viscosity of a petroleum product with temperature.
3.1.1.1 Discussion - For oils of similar kinematic viscosity, the higher the viscosity index the smaller the effect of temperature on its kinematic viscosity.
NOTE 1 - Viscosity index is also used in Terminology D1695 in a definition unrelated to that in 3.1.1.