scope:

This practice(Footnote 2) covers 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.

NOTE 1 - The results obtained from the calculation of VI from kinematic viscosities determined at 40 and 100°C are virtually the same as those obtained from the former VI system using kinematic viscosities determined at 37.78 and 98.89°C.

Procedure A - For petroleum products of viscosity index up to and including 100.

Procedure B - For petroleum products of which the viscosity index is 100 or greater.

This standard does not apply to petroleum products with kinematic viscosities less than 2.0 mm2/s (cSt) at 100°C. Table 1 given in this practice applies to petroleum products with kinematic viscosities between 2 and 70 mm2/s (cSt) at 100°C. Equations are provided for calculating viscosity index for petroleum products having kinematic viscosities above 70 mm2/s (cSt) at 100°C.

NOTE 2 - 1 cSt = 1 mm2/s = 10⁻⁶m/s.

In cases where kinematic viscosity data are not available at temperatures of 40 and 100°C, an estimate may be made of the viscosity index by calculating the kinematic viscosity at temperatures of 40 and 100°C from data obtained at other temperatures. Such viscosity index data may be considered as suitable for information only and not for specification purposes. See Test Method D 341, Annex A1.

The kinematic viscosity values are determined with reference to a value of 1.0034 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 D 445, IP 71, ISO 3104, or ISO 2909.

The values stated in SI units are to be regarded as the standard.

Footnote 2 - Supporting data (Metrication of Viscosity Index System Method D 2270) have been filed at ASTM International Headquarters and may be obtained by requesting Research Report RR: D02-1009.