ISO 14644 Cleanroom Classification Explained | Cleanroom Standards Guide
When designing or operating a cleanroom, understanding the ISO 14644 cleanroom classification is essential. This international standard defines how cleanrooms are categorized based on the concentration of airborne particles, ensuring consistent quality and contamination control across industries such as semiconductors, pharmaceuticals, biotechnology, and electronics manufacturing.
What Is ISO 14644?
ISO 14644 is the international standard for cleanroom design, operation, and performance. It replaced the older Federal Standard 209E and is now the global benchmark for measuring and controlling airborne particulate contamination.
The standard consists of multiple parts, with ISO 14644-1 focusing on the classification of air cleanliness by particle concentration.
Cleanroom Classification According to ISO 14644-1
The cleanroom classification ranges from ISO Class 1 (the cleanest) to ISO Class 9 (the least clean). Each class specifies the maximum allowable number of particles per cubic meter of air at specific particle sizes (measured in micrometers, µm).
| ISO Class | Maximum Particles ≥ 0.1 µm / m³ | Typical Applications |
|---|---|---|
| ISO 1 | 10 | Advanced semiconductor & nano fabrication |
| ISO 3 | 1,000 | Semiconductor wafer processing |
| ISO 5 | 100,000 | Pharmaceutical filling areas, microelectronics |
| ISO 7 | 352,000,000 | Medical device assembly, injection molding |
| ISO 8 | 35,200,000,000 | General industrial cleanrooms |
How ISO Cleanroom Classes Are Determined
To determine a cleanroom’s ISO class, particle counters are used to measure the number and size of particles present in the air. The measurement data is compared to the limits defined in ISO 14644-1. The cleanliness class determines the filtration requirements, airflow velocity, and cleanroom design.
Key Factors Affecting Cleanroom Classification:
- Air filtration system (HEPA or ULPA filters)
- Air changes per hour (ACH)
- Airflow pattern (laminar or turbulent flow)
- Personnel and equipment contamination control
- Maintenance and cleaning protocols
ISO 14644 vs. Federal Standard 209E
Before ISO 14644, cleanrooms were classified by Federal Standard 209E (e.g., Class 100, Class 10,000). Today, ISO classes have replaced this system. For example:
- Class 100 ≈ ISO 5
- Class 10,000 ≈ ISO 7
- Class 100,000 ≈ ISO 8
Why Cleanroom Classification Matters
Proper classification under ISO 14644 ensures product quality, process reliability, and compliance with international standards. It also helps companies meet the requirements of FDA, GMP, and EU standards for critical manufacturing environments.
How to Choose the Right Cleanroom Class
The suitable ISO class depends on your application and production requirements:
- Semiconductors: ISO 1–5
- Pharmaceuticals: ISO 5–8
- Medical Devices: ISO 7–8
- Precision Assembly: ISO 6–8
Conclusion
The ISO 14644 cleanroom classification system provides a clear framework for defining cleanliness levels and maintaining controlled environments across various industries. Understanding these standards helps ensure your cleanroom is built for efficiency, compliance, and long-term success.
