Classification of Compressed Air Quality

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This guide has been prepared to show you the classifications of compressed air quality. This can help when trying to find the most suitable air compressor for your production.


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ISO standard 8573.1 for the classification of compressed air quality

Quality class Solid particle content Water content Oil content
Max. size mu
Max. amount mg/m³  Dew point °C  Amount g/m³
Max. amount mg/m³ 
1
0.1
0.1 - 70 0.003  0.01
2  1 1 - 40 0.11 0.1
3 5 5 - 20 0.88 1.0
4  40 10 + 3 6.0 5
5 - - + 7 7.8 25
6  - - + 10 9.4 -

Typical requirements for compressed air quality classes according to ISO 8573.1 for some users

Application areas Quality Class
Solid particle content Water content Oil content
Air stirring 3 6 3
Air motors, large  4 5-2 5
Air motors, minature  3 4-2 3
Air turbines  2 3 3
Transportation of granulates  3 5 3
Transportation of powder  2 4 2
Fluidistors  2 3-2 2
Foundry machinery  4 5 5
Contact with provisions  2 4 1
Pneumatic tools, industrial  4 6-5 4
Mining Machinery  4 6 5
Packaging machines  4 4 3
Textile machinery  4 4 3
Pneumatic cylinders
3 4 5
Film Handling  1 2 1
Precision Regulators  3 3 3
Process Instruments
2 3 3
Sand blasting  - 4 3
Spray painting  3 4-3 3
Welding machines  4 5 5
  5 4 5

The air's water content at different dew points

Dew Point °C g/m³ Dew Point °C g/m³ Dew Point °C g/m³ Dew Point °C g/m³
+ 100
588.208 58  118.119 16  13.531 -26  0.51
98  550.375 56  108.2 14  11.987 -28  0.41
96
514.401 54  98.883 12  10.611 -30  0.33
94  480.394 52  90.247 10  9.356 -32  0.271
92  448.308 50  82.257 8  8.243 -34  0.219
90  417.935 48  74.871 6  7.246 -36  0.178
88  389.225 46  68.056 4  6.356 -38  0.144
86  362.124 44  61.772 2  5.571 -40  0.117
84  336.661 42  44.989 ±0  4.868 -42  0.093
82  311.616 40  50.672 -2  4.135 -44  0.075
80  290.017 38  45.593 -4
3.513 -46
0.061
78  268.806 36  41.322 -8  2.984 -48  0.048
76  248.841 34
37.229 -12  2.156 -52  0.031
72  212.648 30  30.078 -14  1.81 -54
0.024
70  196.213 28  26.97 -16  1.51 -56  0.019
68
180.855 26
24.143 -18
1.27 -58  0.015
66 166.507 24
21.587 -19  1.05 -60  0.011
64  153.103 22
19.252 -20  0.88 -70 0.0033
62
140.659 20  17.148 -22
0.73 -80
0.0006
60
129.02 18  15.246 -24
0.61 -90  0.0001
Classification of Compressed Air Image

Continue through our compressed air guide:
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Compressed Air Budget - Part One >