Particle Contamination – ISO And NAS Cleanliness Codes

Oil cleanliness is critical to the reliability of your machinery. As technology advances, the demands placed on a lubricant are ever-increasing: pressures and temperatures are higher, reservoir sizes are smaller and component tolerances are tighter.

Code ISO 4406 Number of Particles/100ml NAS 1638
>4μm >6μm >14μm
23/21/18
22/20/18
22/20/17
8,000,000
4,000,000
4,000,000
2,000,000
1,000,000
1,000,000
250,000
250,000
130,000
12
-
11
Very Contaminated - Breakdowns Inescapable
22/20/16
21/19/16
20/18/15
4,000,000
2,000,000
1,000,000
1,000,000
500,000
250,000
64,000
64,000
32,000
-
10
9
19/17/14
18/16/13
500,000
250,000
130,000
64,000
16,000
8,000
8
7
Minimum required cleanliness class for high pressure -
servo valve hydraulic systems, new/fresh oil DIN51524
17/15/12
16/14/12
130,000
64,000
32,000
16,000
4,000
4,000
6
-
16/14/11
15/13/10
14/12/9
13/11/8
64,000
32,000
16,000
8,000
6,000
8,000
4,000
2,000
2,000
1,000
500
250
5
4
3
2
(ACHIEVEABLE) Results After CARDEV Microfiltration
12/10/8
12/10/7
12/10/6
4,000
4,000
4,000
1,000
1,000
1,000
250
130
64
-
1
-

100-times magnified, 1 scale mark = 10μm

NAS Class 3

NAS Class 8

NAS Class 12