SAE AS4059 Rev G - Hydraulic Fluid Contamination Classes

SAE AS 4059 Revision G Aerospace Fluid Power - Contamination Classification for Hydraulic Fluids

Particle Size Class According to SAE AS 4059 Rev. G, Table 1.1	Size x in µm
Class 1	5 ≤ x < 15
Class 2	15 ≤ x < 25
Class 3	25 ≤ x < 50
Class 4	50 ≤ x < 100
Class 5	100 ≤ x

Particle Size Class According to SAE AS 4059 Rev. G, Table 2.1	Size x in µm
Class 1	1 ≤ x < ∞
Class 2	5 ≤ x < ∞
Class 3	15 ≤ x < ∞
Class 4	25 ≤ x < ∞
Class 5	50 ≤ x < ∞
Class 6	100 ≤ x < ∞

1. Particle Concentration Classification

Depending on the normalization parameter the particle count per size class is expressed in contamination level as shown in the table:

Particle Count per 100ml up to including, according to SAE AS 4059, Table 2.1
*These values differ from the standard values (0/0/1/1). With the standard values an automated assignment to a contamination level is not possible.
Contamination Level	5 ≤ x < 15	15 ≤ x < 25	25 ≤ x < 50	50 ≤ x < 100	100 ≤ x
00	125.00	22.00	4.00	1.00	0*
0	250.00	44.00	8.00	2.00	0.50*
1	500.00	89.00	16.00	3.00	1.00*
2	1.000.00	178.00	32.00	6.00	1.50*
3	2000.00	356.00	63.00	11.00	2.00
4	4000.00	712.00	126.00	22.00	4.00
5	8000.00	1425.00	253.00	45.00	8.00
6	16000.00	2850.00	506.00	90.00	16.00
7	32000.00	5700.00	1012.00	180.00	32.00
8	64000.00	11400.00	2025.00	360.00	64.00
9	128000.00	22800.00	4050.00	720.00	128.00
10	256000.00	45600.00	8100.00	1440.00	256.00
11	512000.00	91200.00	16200.00	2880.00	512.00
12	1024000.00	182400.00	32400.00	5760.00	1024.00
>12	∞	∞	∞	∞	∞

Particle Count per 100ml up to including, according to SAE AS 4059 Rev G, Table 2.1.
*These values differ from the standard values (0/0/1/1). With the standard values an assignment to a contamination level is not possible.
Contamination Level	1 ≤ x < ∞	5 ≤ x < ∞	15 ≤ x < ∞	25 ≤ x < ∞	50 ≤ x < ∞	100 ≤ x < ∞
000	195.00	76.00	14.00	3.00	1.0	0.00*
00	390.00	152.00	27.00	5.00	1.5	0.25*
0	780.00	304.00	54.00	10.00	2.00	0.50*
1	1560.00	609.00	109.00	20.00	4.00	1.00*
2	3120.00	1217.00	217.00	39.00	7.00	1.50
3	6250.00	2432.00	432.00	76.00	13.00	2.00
4	12500.00	4864.00	864.00	152.00	26.00	4.00
5	25000.00	9731.00	1731.00	306.00	53.00	8.00
6	50000.00	19462.00	3462.00	612.00	106.00	16.00
7	100000.00	38924.00	6924.00	1224.00	212.00	32.00
8	200000.00	77849.00	13849.00	2449.00	424.00	64.00
9	400000.00	155698.00	27698.00	4898.00	848.00	128.00
10	800000.00	311396.00	55396.00	9796.00	1696.00	256.00
11	1600000.00	622792.00	110792.00	19592.00	3392.00	512.00
12	3200000.00	1245584.00	221584.00	39184.00	6784.00	1024.00
>12	∞	∞	∞	∞	∞	∞

2. Normalization

The absolute particle number is divided by the applied oil volume and standardized to 100ml.

Default Values for Particle Typification

Particle Type	Description
Fiber	Length (Feret Max) > 100 µm and Length/Width (Feret Max/Feret Min) > 10 µm
Particle	If the particle is not in the range of Fiber, it is a particle.

As a Supervisor, you can edit the values in the Standard Template Editor, see Standard Template Editor.

Occupancy Rate

The occupancy rate is a measurement value to describe the quality of the specimen preparation in terms of particle density, and the distribution of particles on the effective filter area. The calculation is performed as follows:

Sum of the particle area of all detected particles in relation to measurement frame area. Value in %.

For more information, see

About Filters and Occupancy Rate
Occupancy Rate (Oil, Lubricants) Tool

3. Core parameter for size class distribution

Length = Feret Max (default use case), see Feret Maximum