Industrial fluids kinematic viscosity according to ISO 3448, DIN 51519
ISO-VG (Viscosity Grade) classes apply only for industrial lubricating oils. For engine oil check SAE J300 and SAE J306 for gear oils. A viscosity grades classification or standard known as the ISO VG (International Standards Organization Viscosity Grade). Settled in 1975 by a joint committee of International Standards Organization (ISO), American Society for Testing and Materials (ASTM), Society for Tribologists and Lubrication Engineers (STLE), British Standards Institute (BSI), and Deutsches Institute for Normung (DIN).
Lubricant viscosity performs a prime role against friction and wear. ISO viscosity classification system or ISO Viscosity grades also called ISO VG contains 18 viscosity grades. ISO VG are based on kinematic viscosity of the lube oil/fluid at 40°C. The ISO system is primarily used for hydraulic oil, industrial oils, such as turbine oils, compressor oils and others.
Viscosity table/chart as per ISO 3448 for industrial fluids.
| ISO viscosity grade classifications |
Midpoint kinematic viscosity, cSt @40°C |
Kinematic viscosity, cSt @40°C | |
|---|---|---|---|
| Minimum | Maximum | ||
| ISO VG 2 | 2.2 | 2.0 | 2.4 |
| ISO VG 3 | 3.2 | 2.9 | 3.5 |
| ISO VG 5 | 4.6 | 4.1 | 5.1 |
| ISO VG 7 | 6.8 | 6.1 | 7.5 |
| 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 | 29.8 | 35.2 |
| ISO VG 46 | 46 | 41.1 | 50.6 |
| ISO VG 68 | 68 | 61.2 | 74.8 |
| ISO VG 100 | 100 | 90.0 | 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 | 1,000 | 900 | 1,100 |
| ISO VG 1500 | 1,500 | 1,350 | 1,650 |
| ISO VG 2200 | 2,200 | 1,980 | 2,420 |
| ISO VG 3200 | 3,200 | 2,880 | 3,520 |
Viscosity grade numbers of the ISO are the same as those of ASTM (The American Society of Testing and Materials) and BSI (British Standards Institution), with the difference that the viscosities for the ISO grades are measured at 40 °C, while those of the ASTM and BSI are measured at 100 °F (37.8 °C). Lubricants of a given ASTM or BSI grade are slightly more viscous than lubricants of the corresponding ISO grade.