Particle counting – determine fluid cleanliness to ISO4406 / NAS / SAE4059. Achieve cleaner oil by monitoring it’s cleanliness with oil analysis.

This article will answer the following questions.

  • Is my lube oil contaminated?

  • Why do lubricating oils become contaminated?

  • Is my oil filter working and which oil filter should I use?

  • What is a ISO4406, ISO4407, NAS1638 or SAE4059 Particle count?

  • What sizes of particles are tested in ISO 4406 Analysis?

  • How small are the particles my filter removes?

Particle count – Particle counts measure the relative cleanliness of a fluid. This can be performed at different particle sizes from 4 microns all the way up to 70 microns. The most common cleanliness method is the ISO code system that measures the number of particles at 4, 6 and 14 microns. Traditional thinking suggests particles between 6 and 14 microns are the most damaging to equipment, but current thinking suggests smaller particle sizes such as 4 microns may also be damaging to systems with small machine tolerances, hence these are measured too. To easily express the cleanliness and allow comparison of large numbers. The code is expressed from smallest to largest from left to right, so a code of 20/19/15 means