ISO 4406 Contamination Chart



Studies have shown that for each grade the ISO code is lowered, the life of a hydraulic component can be doubled or tripled!  As shown in the chart, new oil is approximately rated at 18/15.  Kleenoil Bypass Filters will attain ISO 4406 to a standard of 14/9!

The ISO 4406 cleanliness level standard is used to reference the number of particles greater than 5 and greater than 15 microns in a known volume. For our usage, this volume will be 1 ml. The number of 5+ micron particles is used as a reference point for “silt” particles. The 5 - 15 size range indicates the quantity  of larger particles present, which contribute greatly to potential catastrophic component failure.  Now, the way the ISO chart lists the “ISO Code” is with a two number system. For example, the approximate rating of new oil off the store shelf would be rated at 18/15.  

In this two number system, the first number indicates the number of particles that are greater than 5 micron in size. The second number after the / indicates the number of particles that are greater than 15 micron in size.  Ideally, the lower you can get the two numbers in the ISO chart, the less internal damage there will be inside your engine or hydraulic system.  To ensure that you achieve the most efficient and relative results, it is important to maintain an oil analysis program.