Particulate Contamination
Particulate contamination in fluids can be caused by a number of factors:-
External Ingress
- Open tanks/reservoirs
- Ports left open when servicing
- Quick connect couplings
- Worn seals (Cylinders and motors)
Component Wear
Poor housekeeping
- Not filtering new/replacement fluid
- Poor maintenance procedures
- Not changing out dirty/clogged traditional filters
The levels of particulate contamination in a fluid reduces the ability for a fluid to lubricate thereby greatly adding to the wear
and failure of components.
Contamination is the major contributory factor to unexpected component failure and system inefficiency.
Component recommended max acceptable ISO Code
- Flow Control Valves 20/18/15
- Gear Pumps/Motors 19/17/14
- Diesel Injectors 18/16/13
- High Pressure Pumps/Motors 18/16/13
- Proportional Hydraulics 17/15/12
- Servo Valves 16/14/11
The traditional method to achieve these cleanliness levels is hot oil flushing of a system, while flushing is essential for new systems,
unfortunately on mature system’s this method only allows for a snapshot cleanliness of the system, as soon as the flushing system
is disconnected contamination is immediately reintroduced.
Flushing also does not overcome or address the normal ingress of contamination to a system.
How Particulate Contamination is Classified
When fluid analysis is undertaken, the contamination level is predominantly classified as a three number ISO code eg, 17/15/12.
There are also alternative contamination classes which have historically been used such as NAS and SAE, the equivalent codes can
be seen on this comparison table.
As such ISO 14/12/09 is equivalent to NAS 3 and SAE 0 and so on
| ISO/NAS/SAE Comparrison Table | ||
| ISO/DIS 4406 | NAS 1638 | SAE 749 |
| 13/11/08 | 2 | |
| 14/12/09 | 3 | 0 |
| 15/13/10 | 4 | 1 |
| 16/14/11 | 5 | 2 |
| 17/15/12 | 6 | 3 |
| 18/16/13 | 7 | 4 |
| 19/17/14 | 8 | 5 |
| 20/18/15 | 9 | 6 |
| 21/19/16 | 10 | |
| 22/20/17 | 11 | |
| 23/21/18 | 12 | |
Did You Know
If you run a pump (60 litres per minute) at ISO Code 20/18/15 for 8 hours a day you will pass around 46kg of particulate
through your system in a year, if you reduce the ISO code to 19/17/14 this would reduce to around 23Kg a 50% reduction
The ISO Code numbers refer to ranges depicting the number of particles ‘larger than’ 4 micron, 6 micron and 14 micron per 1mL respectively.
Obviously, as 6 micron and 14 micron particles are both larger than 4 micron, those particles are all also present in the first number. The second number
only shows particles larger than 6 micron. The last number only shows particles larger than 14 micron.
| ISO 4406 Code | 24 | 23 | 22 | 21 | 20 | 19 | 18 | 17 | 16 | 15 | 14 | 13 | 12 | 11 | 10 | 9 | 8 | 7 | 6 | 5 | 4 | 3 | 2 | 1 | 0 | |
| Number of Particles per mL | More Than | 40,000 | 30,000 | 20,000 | 10,000 | 5,000 | 2,500 | 1,300 | 640 | 320 | 160 | 80 | 40 | 21 | 10 | 5 | 2.5 | 1.3 | 0.64 | 0.32 | 0.6 | 0.08 | 0.04 | 0.02 | 0.01 | 0.005 |
| Up to and Including | 80,000 | 60,000 | 40,000 | 20,000 | 10,000 | 5,000 | 2,500 | 1,300 | 640 | 320 | 160 | 80 | 40 | 20 | 10 | 5 | 2.5 | 1.3 | 0.7 | 0.3 | 0.2 | 0.1 | 0.04 | 0.02 | 0.01 | |
The above table also provides a clear picture of the percentage reduction in particulates by improving the ISO code by a single code, i.e.
improving from an ISO code of 21 to 20 can reflect up to a 50% reduction in particulate.
Maintaining a clean system provides you with equipment reliability and lower maintenance costs, by the use of the innovative Delta Xero unit
configured to maintain fluid cleanliness is the way forward.
Please get in touch with Micron Eagle to assess your requirements