Industrial Lubricants

Viscosity Classification - ISO 3448

The ISO viscosity classification is recommended for industrial applications. The reference temperature of 40 °C represents the operating temperature in machinery. Each subsequent Viscosity grade (VG) within the classification has approximately a 50% higher viscosity, whereas the minimum en maximum values of each grade ranges ±10% from the mid point. For example, ISO VG 22 refers to a viscosity grade of 22 cSt ± 10% at 40°C.

The viscosity at different temperatures can be calculated using the viscosity at 40°C and the viscosity index (VI), which represents the temperature dependency of the lubricant.

ISO 3448 Viscosity class Kinematic viscosity at 40°C [mm2/s = cSt]
  Mid-point Minimum Maximum
ISO VG 2 2.2 1.98 2.42
ISO VG 3 3.2 2.88 3.52
ISO VG 5 4.6 4.14 5.06
ISO VG 7 6.8 6.12 7.48
ISO VG 10 10 9.0 11.0
ISO VG 15 15 13.5 16.5
ISO VG 22 22 19.8 24.2
ISO VG 32 32 28.8 35.2
ISO VG 46 46 41.4 50.6
ISO VG 68 68 61.2 74.8
ISO VG 100 100* 90 110
ISO VG 150 150 135 165
ISO VG 220 220 198 242
ISO VG 320 320 288 352
ISO VG 460 460 414 506
ISO VG 680 680 612 748
ISO VG 1000 1000 900 1100
ISO VG 1500 1500 1350 1650

Any viscosity can be obtained with a mixture of two ISO VG base oils