- ISO Class 1-5: These environments are used in industries requiring extremely low levels of contamination, such as semiconductor manufacturing, nanotechnology, and some high-end pharmaceutical production.
- ISO Class 6-7: Commonly found in the production of medical devices, pharmaceutical packaging, and optics.
- ISO Class 8-9: Typically used in less sensitive applications, such as automotive manufacturing, where some level of contamination can be tolerated.
Clean rooms are classified by the number and size of particles permitted per volume of air. The International Organization for Standardization (ISO) provides a widely recognized standard for clean rooms, known as ISO 14644-1. This standard defines clean rooms based on the number of particles of a specific size in a cubic meter of air. The lower the ISO class, the cleaner the room.