An ISO 3 cleanroom is an environment with a high level of cleanliness, defined by the ISO 14644-1 international standard. Its cleanliness level is just below that of ISO 1 and ISO 2 cleanrooms. These cleanrooms are typically used in high-tech industries that require extremely strict particle cleanliness standards, such as semiconductor manufacturing, precision optics, nanotechnology, and aerospace.
ISO 3 cleanroom cleanliness standards
ISO 3 cleanroom cleanliness standards specify that particles larger than 5.0μm are not allowed to be present.
| Relative particle size（μm） | Maximum number of particles allowed per cube |
| ≥0.1μm | 1000 |
| ≥0.2μm | 237 |
| ≥0.3μm | 102 |
| ≥0.5μm | 35 |
| ≥1.0μm | 8 |
| ≥5.0μm | 0 |
Key Features of an ISO 3 Cleanroom:
High-Efficiency Airflow System
- The cleanroom uses ULPA filters, with a filtration efficiency of 99.9995% at 0.12 μm.
- It employs unidirectional airflow to ensure particles are quickly removed from the air.
High Air Exchange Rate
- Air changes per hour: 300-540, significantly higher than the 20-60 per hour in ISO 7/8 cleanrooms.
- The cleanroom maintains a 99.9% unidirectional airflow mode, ensuring consistent clean airflow.
Stable Environmental Conditions
- Temperature control: 20-22°C, with a fluctuation range of ±0.5°C.
- Humidity control: 40-50% RH, preventing static electricity buildup.
- Strict ESD (Electrostatic Discharge) management to protect sensitive components from damage.
Applications of ISO 3 Cleanrooms
ISO 3 cleanrooms are used in industries where extreme particle control is essential. Key applications include:
- Semiconductor Manufacturing – Wafer fabrication, photolithography, and chip packaging
- Biopharmaceuticals – Sterile drug production, cell culture, and vaccine manufacturing
- Precision Optics – High-end laser systems and nanophotonic devices
- Aerospace & Aviation – Space probe assembly and satellite component manufacturing
Conclusion
An ISO 3 cleanroom provides an ultra-clean environment, making it ideal for high-tech manufacturing and research that require minimal particle contamination. When designing or selecting an ISO 3 cleanroom, factors such as particle cleanliness levels, airflow patterns, and environmental controls must be carefully considered to ensure optimal cleanliness and compliance with industry standards.
