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 |
Continue through our compressed air guide:
< FAQ Sheets: Screw Compressors
Compressed Air Budget - Part One >