ISO VISCOSITY CLASSIFICATION SYSTEM

Royal industrial oils are graded in accordance with the ISO Viscosity Classification System, approved by the International Standards Organization (ISO). The ISO system is based upon viscosity at only one temperature, 40°C. ISO viscosity ranges are summarized in the table below:

ISO Viscosity Grades
Mid-Point
cSt @ 40°C
Viscosity Ranges
cSt @ 40°C
   
Minimum
Maximum
2
2.2
1.98
2.42
3
3.2
2.88
3.52
5
4.6
4.14
5.06
7
6.8
6.12
7.48
10
10
9.00
11.0
15
15
13.5
16.5
22
22
19.8
24.2
32
32
28.8
35.2
46
46
41.4
50.6
68
68
61.2
74.8
100
100
90.0
110
150
150
135
165
220
220
198
242
320
320
288
352
460
460
414
506
680
680
612
748
1000
1000
900
1100
1500
1500
1350
1650