By [email protected] — Charting the depths of expertise
In China, the U.S. Federal Standard FED-STD-209E has been commonly used to classify cleanrooms; however, this standard has been widely superseded internationally by the ISO 14644-1 cleanroom classification standard. According to FED-STD-209E, a Class 100 cleanroom is defined as an area with no more than 100 particles ≥0.5µm per cubic foot of air. The ISO 14644-1 standard is stricter; Class 100 corresponds to ISO Class 5 and adds requirements for particles smaller than 0.5µm.
U.S. Federal Standard FED-STD-209E Cleanroom Classifications
This standard is based on imperial units, and the class name directly corresponds to the number of particles ≥0.5µm per cubic foot of air. For example, Class 100 means there are no more than 100 particles ≥0.5µm per cubic foot.
Unit: Maximum allowable particles per cubic foot (particles/ft³) at ≥ specified particle size
| Cleanroom Class | ≥ 0.1 µm | ≥ 0.2 µm | ≥ 0.3 µm | ≥ 0.5 µm | ≥ 5 µm | Corresponding ISO Class |
|---|---|---|---|---|---|---|
| Class 1 | 35 | 7 | 3 | 1 | ISO Class 3 | |
| Class 10 | 350 | 75 | 30 | 10 | ISO Class 4 | |
| Class 100 | 100 | ISO Class 5 | ||||
| Class 1,000 | 1,000 | 7 | ISO Class 6 | |||
| Class 10,000 | 10,000 | 70 | ISO Class 7 | |||
| Class 100,000 | 100,000 | 700 | ISO Class 8 |
ISO 14644-1 Cleanroom Classifications
As the current international standard, ISO 14644-1 classifies the air cleanliness of cleanrooms and controlled environments based on the concentration of airborne suspended particles.
Unit: Maximum allowable particles per cubic meter (particles/m³) at ≥ specified particle size
| Cleanroom Class | ≥ 0.1 µm | ≥ 0.2 µm | ≥ 0.3 µm | ≥ 0.5 µm | ≥ 1 µm | ≥ 5 µm | Corresponding FED-STD-209E Class |
|---|---|---|---|---|---|---|---|
| ISO Class 1 | 10 | 2 | |||||
| ISO Class 2 | 100 | 24 | 10 | 4 | |||
| ISO Class 3 | 1,000 | 237 | 102 | 35 | 8 | Class 1 | |
| ISO Class 4 | 10,000 | 2,370 | 1,020 | 352 | 83 | Class 10 | |
| ISO Class 5 | 100,000 | 23,700 | 10,200 | 3,520 | 832 | 29 | Class 100 |
| ISO Class 6 | 1,000,000 | 237,000 | 102,000 | 35,200 | 8,320 | 293 | Class 1,000 |
| ISO Class 7 | 352,000 | 83,200 | 2,930 | Class 10,000 | |||
| ISO Class 8 | 3,520,000 | 832,000 | 29,300 | Class 100,000 | |||
| ISO Class 9 | 35,200,000 | 8,320,000 | 293,000 | Room Air |
