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Air Changes per Hour in ISO Class 8 Cleanroom

  • Author:Jason Peng

  • Cleanroom Engineering Technology Manager of Deiiang Company.

    Product R&D Manager of GDC Inc. Cleanroom Equipment Manufacturing Company.

    Executive Director of Guangdong Cleanroom Industry Association of China.

    Engaged in R&D of related products for 15 years, with rich relevant technical experience

  • 2025-07-06  |  Visits:

Understanding Air Changes Per Hour in ISO Class 8 Cleanrooms

Maintaining cleanliness and safety through effective air exchange rates

Particle Count in ISO Class 8 Cleanrooms

ISO Class 8 Cleanrooms allow for up to 3,520,000 particles per cubic meter, with a particle size of 0.5 microns or larger. Maintaining this level of air cleanliness requires effective filtration systems and sufficient air exchange rates to dilute and remove airborne particulates. As the specifications for cleanliness are strict, innovative solutions from companies like Deiiang™ are vital in creating efficient cleanroom environments.

cleanliness level table.jpg

Why cleanroom air Change Rates Matter

Air change rates are critical in ensuring that airborne particles and contaminants are efficiently removed from the cleanroom environment. The ACH value indicates how many times the air within the cleanroom is replaced in an hour.


Key Point:

For ISO Class 8 cleanrooms, maintaining a typical ACH range from 20 to 30 is essential to ensure that particulate levels do not exceed acceptable limits.

This careful management of air changes helps maintain compliance with ISO standards and supports high-quality production processes.

HEPA-Filtered Air

HEPA filters are key components in cleanroom HVAC systems, integral for maintaining the required air cleanliness. With a filtration efficiency of 99.97% for particles as small as 0.3 microns, HEPA filters ensure that incoming and circulating air remains free of harmful contaminants.

HEPA Filter Specifications

  • Filtration efficiency: 99.97% for 0.3 micron particles
  • Key component of cleanroom HVAC systems
  • Ensures incoming air is free of contaminants
  • Strategic placement is crucial for effectiveness
cleanroom HAVC hepa work principle

Purpose of Air Changes

The primary purpose of air changes in A CleanRoom environment is to control contamination levels effectively. Regular air change cycles flush out contaminants, maintain air quality, and support temperature and humidity control.

Key Purposes of Air Changes:

  • Flushing out contaminants and pollutants
  • Maintaining consistent air quality standards
  • Supporting temperature and humidity control
  • Preventing the buildup of harmful particles
  • Ensuring compliance with strict cleanroom specifications

Calculating Air Changes Per Hour

Calculating ACH involves determining the volume of the cleanroom and the total airflow supply rate to the room. The formula used is:

ACH = (Airflow Rate (cubic meters/hour)) / (Room Volume (cubic meters))

Using this formula, Cleanroom designers and operators can ensure that air change rates comply with ISO standards for their specific CleanRoom class. Proper calculation is essential for maintaining the required level of cleanliness and ensuring operational efficiency.

Best Practices for Achieving Required ACH

Achieving the desired ACH involves more than just calculation; it requires effective implementation and ongoing management. Here are some key best practices:


Regular Maintenance

Ensuring that HVAC and filtration systems are well-maintained to provide consistent airflow and filtration efficiency.


System monitoring

Utilizing advanced monitoring systems to track airflow patterns and adjust as necessary.


Optimized Layout

Designing cleanroom layouts that facilitate efficient airflow distribution, minimizing dead zones.

Conclusion: Elevating Cleanroom standards through Effective ACH Management

Cleanroom air changes rates refers to how many times per hour the cleanroom air is passed thru the HEPA filtration. The more air changes per hour the cleaner the cleanroom. An ISO-8/class 100k cleanroom requires 20 air changes per hour. A cleaner ISO-7/class 10k cleanroom requires 60 air changes per hour.

Deiiang™, alongside design experts like Jason.peng, continues to innovate in providing solutions that enhance cleanroom efficacy and reliability. Ensuring these practices and standards are met not only supports regulatory compliance but also contributes to the integrity and precision of the products manufactured within these controlled environments.

"Effective ACH management is the cornerstone of maintaining cleanroom integrity, ensuring both compliance and product quality." - Deiiang Jason.peng

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Cleanroom Insiders Expert Team

Deiiang's expert team specializes in designing and constructing state-of-the-art cleanrooms tailored to meet diverse industry needs. With a focus on innovation and compliance, we deliver pristine environments that ensure operational excellence and product integrity.

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