KEVOS® MAKEOS · Maintenance
ISO 4406 Oil Cleanliness Code from Particle Counts
What ISO 4406 cleanliness code do these particle counts give, and does the oil meet its target?
ISO 4406 range numbers for particles of 4, 6 and 14 µm and larger per millilitre of oil, from counts per millilitre or per sample volume, with the three-part code and a check against a target code for each size.
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How this tool works
Inputs, units and where to find them
| Input | Unit | Typical source |
|---|---|---|
| Sample volume counted | mL | Volume of oil the counts refer to (1 mL if counts are already per millilitre). |
| Particles ≥ 4 µm in the sample | Count of particles 4 µm(c) and larger. | |
| Particles ≥ 6 µm in the sample | Count of particles 6 µm(c) and larger. | |
| Particles ≥ 14 µm in the sample | Count of particles 14 µm(c) and larger. | |
| Target code | ||
| Target range number, 4 µm | Target range number at 4 µm (from the machine or component maker). | |
| Target range number, 6 µm | Target at 6 µm. | |
| Target range number, 14 µm | Target at 14 µm. | |
Method and formulas
- Counts are converted to particles per millilitre.
- Range numbers double with each step: number R covers more than 0.01 × 2^(R−1) up to 0.01 × 2^R particles per mL, so R = ⌈log₂(count per mL ÷ 0.01)⌉.
- The code is written R₄/R₆/R₁₄, for example 21/19/17.
- Example: 15000, 3000 and 1000 particles per mL give ISO 21/19/17.
Limitations
- Counts must come from a calibrated counter per ISO 11171 sizes µm(c).
- Range numbers above 28 or below 1 are reported at the limit as calculated.
- Example values are illustrations. Replace them with values for your actual task.
Typical uses
- Turn a particle count report into an ISO code
- Check oil against the target cleanliness for a machine
- Track filtration improvements over time
Who it is for
- Reliability engineers
- Lubrication technicians
- Maintenance engineers
What you get
- ISO code (4/6/14 µm)
- Count per millilitre for each size
- Comparison with the target
Interpreting the result
- Each range number down halves the particle count; one step cleaner can noticeably extend component life.
References
- Machinery’s Handbook, 29th edition (Industrial Press, 2012), printed pp. 2439–2441. Topic reference; no source tables or recommended settings are reproduced.
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Open the ISO 4406 Oil Cleanliness Code from Particle Counts calculator
