There are several classifications of cleanrooms, based on the allowable particle count per volume of air. The most common standard used to classify cleanrooms is ISO 14644-1.
Cleanrooms are classified based on the number and size of particles permitted per volume of air. A cleanroom maintains a controlled level of contamination, specified by the number of particles per cubic meter or cubic foot at a specified particle size. Different industries and applications require different levels of cleanliness, which leads to these various classifications.
Cleanroom Classifications based on ISO 14644-1
The ISO 14644-1 standard defines nine classes of cleanrooms, from ISO 1 (cleanest) to ISO 9 (least clean). Here is a summary of some common ISO classes:
| Class | >0.1 um (Particles per cubic meter) | FED STD 209E equivalent |
|---|---|---|
| ISO 3 | 1,000 | Class 1 |
| ISO 4 | 10,000 | Class 10 |
| ISO 5 | 100,000 | Class 100 |
| ISO 6 | 1,000,000 | Class 1,000 |
It's important to understand that while there are nine official ISO classifications, the type of cleanroom really refers to the classification level it achieves according to the ISO 14644-1 standard. Therefore, you could say there are nine types of cleanrooms when referring to the ISO classes.
Considerations
While the ISO classification defines the "type" of cleanroom based on cleanliness, other factors also influence the design and operation of a cleanroom, such as:
- Airflow patterns: Unidirectional (laminar) or non-unidirectional (turbulent).
- Construction materials: Choosing materials that minimize particle shedding.
- Personnel training: Proper gowning procedures and behavior within the cleanroom.
These factors are critical in maintaining the required cleanliness level for a specific ISO classification, but they don't define fundamentally different "types" of cleanrooms in terms of classification.
