ISO 14644 is the international standard for cleanroom classification and operation. This guide provides a comprehensive overview of the key requirements.

ISO 14644-1: Air Cleanliness Classification

The standard defines 9 cleanliness classes (ISO Class 1-9) based on airborne particle concentration:

• ISO Class 5: ≤ 3,520 particles (≥ 0.5 μm) per m³
• ISO Class 6: ≤ 35,200 particles (≥ 0.5 μm) per m³
• ISO Class 7: ≤ 352,000 particles (≥ 0.5 μm) per m³
• ISO Class 8: ≤ 3,520,000 particles (≥ 0.5 μm) per m³

ISO 14644-2: Monitoring Requirements

Regular monitoring ensures continued compliance:

• Particle counting at defined frequencies
• Pressure differential monitoring
• Temperature and humidity control
• Airflow velocity and volume verification

ISO 14644-3: Test Methods

Standardized test methods include:

1. Particle counting using calibrated instruments
2. Airflow visualization (smoke tests)
3. Filter leak testing (DOP/PAO method)
4. Recovery time testing

Compliance Documentation

Maintain comprehensive records:

• Initial certification reports
• Regular monitoring data
• Filter replacement logs
• Corrective action records