ISO 14644 Cleanroom Classification Chart & ISO Class Air Changes per Hour (ACH)

ISO 14644 offers the definitive classification standard for controlled environments critical to advanced manufacturing.
Understanding the relationship between cleanroom classification and required air changes per hour (ACH) is essential
for selecting appropriate facilities for semiconductor fabrication, pharmaceutical manufacturing, medical device
production, and critical laboratory applications.

This comprehensive chart compares ISO class requirements with standard air change rates,
explicating the critical parameters that determine facility design and operational efficiency

1. ISO Cleanroom Classification Chart (ISO Class 1–9)

The ISO 14644 standard classifies cleanrooms based on particle concentration limits,
with lower numerical classes designating more stringent contamination control requirements.

Our industry-exclusive chart visualizes key parameters:

>1 micro. particles

*Values in parentheses are approximate ranges influenced by:
– Room volume and configuration
– Fume hood cleanroom wall panel dimensions
– Equipment load density
– Required pressure differential management

2. Understanding Air Change Rates (ACH) in ISO Classified Cleanrooms

ISO air change rate requirements correlate directly with risk level, application sensitivity,
and contamination control demands across various GMP-compliant industries.

To maintain proper ISO classification:

• Higher ISO classes (3-6) require >200 ACH to achieve and maintain stringent particle counts
• ISO Class 5 (100,000 class) typically requires 150-300 ACH depending on product risk
• Special process chambers often require significantly higher air changes
• Terminal HVAC velocity and capture efficiency are validated through proper airflow mapping

Common applications and design considerations:

• Pharmaceutical filling areas (ISO Class 5-7) require >200 ACH
• Semiconductor wafer fabrication (ISO Class 1-2) requires 600-1000+ ACH
• Biology safety cabinets (ISO Class 5-6) require specialized airflow patterns
• Affordable cleanroom solutions (ISO Class 7-8) can optimize ACH based on validated performance

3. Selecting Appropriate HVAC Systems for Your Cleanroom

Proper HVAC design is essential to maintain specified ISO classification and particle
concentration targets.

Key considerations for implementing your design include:

• Calculating required air volumes based on room size, personnel density, and equipment
• Utilizing high-efficiency filtration integrated with our cleanroom wall panels system
• Positioning diffusers to provide uniform vertical unidirectional airflow (ISO 14644-3)
• Employing variable air volume (VAV) systems for energy efficiency
• Specifying constant air volume (CAV) systems for process-critical environments
• Implementing positive room pressurization to prevent contamination ingress

When selecting HVAC components, consider:

• Static pressure requirements driven by room configuration
• Power consumption of integrated fan systems
• Sensor placement for real-time monitoring (ISO 14644-2)
• HVAC redundancy requirements per ISO 14644-4

4. Applications Across GMP-Regulated Industries

The ISO classification system provides vital guidance for facilities operating under
various regulatory frameworks:

• Pharmaceutical manufacturing: API synthesis (ISO 5-7), tablet formulation (ISO 7-8)
• Medical device production: Implantable devices assembly (ISO 6-8)
• Semiconductor fabrication: Wafer processing (ISO 1-4) & photolithography
• Bio/pharma R&D: Cell culture operations (ISO 5-6)

For facilities requiring >ISO 7 classification:

• Evaluate cleanroom efficiency through validated monitoring data
• Specify filtration systems with minimum penetration rates
• Implement controlled pressure gradients between zones
• Use self-cleaning design features with our cleanroom wall panels

5. How Cleanroom Wall Panels & Doors Collateral Your ACH Requirements

Sustainable cleanroom construction requires optimized HVAC design in conjunction with
performance-coordinated building systems.

When designing for specific ISO classifications:

• Select wall panels rated for appropriate pressure differentials
• Specify door sealing systems compatible with your air change targets
• Configure room volumes to avoid unnecessary energy waste
• Specify differential pressure sensors to maintain classification integrity

Cleanroom envelope components significantly influence ACH requirements:

• Insulated panels reduce room volume calculations
• High-efficiency cleanroom door systems regulate air containment
• Airlock configurations affect required pressurization differential
• Seamless junctions minimize particle escape points

Conclusion

Understanding the relationship between ISO class and air change rates is essential for
successfully applying controlled environments to critical applications across the process
manufacturing landscape.

To design an optimally performing yet economically viable facility:

• Start by mapping application requirements to appropriate ISO class
• Select cleanroom components rated for required filtration and containment
• Specify HVAC systems capable of delivering required air changes per hour
• Implement robust monitoring according to ISO 14644 standards

Comprehensive Cleanroom Solutions from Farclean

Farclean provides end-to-end turnkey cleanroom engineering: designing and constructing facilities that ensure ISO compliance while offering superior value.

• Nationally recognized cleanroom panels with proprietary manufacturing technology
• Energy-efficient cleanroom air handling systems
• Sealant-free cleanroom doors for superior air containment
• Budget-friendly ISO-compliant solutions (ISO Class 5-8)

Farclean’s modular cleanroom expertise ensures facilities meet not only air change requirements but exceed expectations for dependability, flexibility, and lifecycle value.