The international standard ISO 4406, “Hydraulic fluid power — Fluids — Method for coding the level of contamination by solid particles” provides a framework for reporting the concentration of contamination particles in hydraulic oil using an automatic particle counter (like the Hiac or Accusizer 780). The older standard published in 1987 required particle concentration be reported at two sizes: 5 & 15 µm. This has been replaced in the new standard published in 1999 with three sizes; 4, 6 & 14 µm.
A three number scale is used to report the particle count – the first number represents the particles/ mL > 4 µm, the second number represents the particles/ mL > 6 µm, and the third number represents the particles/ mL > 14 µm. A scale number is assigned to a particle concentration range as shown in Table 1 below.
Number particles/mL
Iso 4406 Pdf Download
| More than | up to/including | Scale number |
| 2 500 000 | 28 | |
| 1 300 000 | 2 500 000 | 28 |
| 640 000 | 1 300 000 | 27 |
| 320 000 | 640 000 | 26 |
| 160 000 | 320 000 | 25 |
| 80 000 | 160 000 | 24 |
| 40 000 | 80 000 | 23 |
| 20 000 | 40 000 | 22 |
| 10 000 | 20 000 | 21 |
| 5 000 | 10 000 | 20 |
| 2 500 | 5 000 | 19 |
| 1 300 | 2 500 | 18 |
| 640 | 1 300 | 17 |
| 320 | 640 | 16 |
| 160 | 320 | 15 |
| 80 | 160 | 14 |
| 40 | 80 | 13 |
| 20 | 40 | 12 |
| 10 | 20 | 11 |
| 5 | 10 | 10 |
| 2,5 | 5 | 9 |
| 1,3 | 2,5 | 8 |
| 0,64 | 1,3 | 7 |
| 0,32 | 0,64 | 6 |
| 0,16 | 0,32 | 5 |
| 0,08 | 0,16 | 4 |
| 0,04 | 0,08 | 3 |
| 0,02 | 0,04 | 2 |
| 0,01 | 0,02 | 1 |
| 0,00 | 0,01 | 0 |
The results should be presented as three numbers separated by slashes, such as 24/20/14. This result would refer to:
ISO/NAS/SAE Code Comparison Table The comparisons relate to particle count data only. To conform to any particular standard, reference should be made to the recommended experimental procedure. ISO/DIS 4406 BS 5540/4 codes Defence Std. 05/42 NAS 1638 SAE 749 Table A Table B 13 / 11 / 08 2 14 / 12 / 09 3 0 15 / 13 / 10 4 1 16 / 14 / 09 400F 16. Hydraulic fluids (per ISO 4406 code chart) were higher than recommended levels for the system components (see fig 2). 1 Machine ISO code. A 22 / 20 / 14 B 23 / 20 / 14 C 23 / 21 / 16 fig 2. Pumps 3000 psi Fixed gear 20/18/15 19/17/15 Fixed vane 20/18/15 19/17/14 18/16/13.
Iso 4406 Pdf Parker
more than 80 000 and up to and including 160 000 particles equal to or larger than 4 μm
more than 5 000 and up to and including 10 000 particles equal to or larger than 6 μm
Iso 4406 Chart Pdf
more than 80 and up to and including 160 particles equal to or larger than 14 μm