Turnkey Cleanroom Solutions And Hvac System Service Provider

Air Change Rate of Cleanrooms

2026-01-19

1.Air Change Rate Requirements for Different Cleanliness Classes

According to the ISO 14644-1 Cleanroom Standard, the reference minimum air change rates (for non-unidirectional flow cleanrooms) for different cleanliness classes are as follows. Unidirectional flow cleanrooms are controlled by sectional wind speed (0.25–0.5 m/s) instead of air change rate.

Cleanliness Class (ISO 14644-1)	Minimum Air Change Rate for Non-unidirectional Flow (times/h)	Typical Application Scenarios
Class 1–5 (High Cleanliness)	Unidirectional flow design (controlled by sectional wind speed)	Semiconductor wafer manufacturing, lithography workshops
Class 6	50–80	Precision electronic components, pharmaceutical aseptic filling
Class 7	20–40	Biopharmaceutical formulation production, medical device assembly
Class 8	10–20	Food packaging, electronic component encapsulation

2.. Key Factors Affecting Air Change Rate

Cleanliness Class

The higher the cleanliness class (smaller the number), the more frequent the air replacement is required.
Indoor Particle Generation Rate

Scenarios with high particle generation (e.g., machining, powder handling) require a 10%–30% increase in the air change rate; scenarios with low particle generation (e.g., laboratories) can have an appropriately reduced rate.
Temperature, Humidity and Pressure Difference Requirements

Cleanrooms need to maintain a positive pressure (5–10 Pa relative to non-clean areas). When the pressure difference is insufficient, the supply air volume needs to be increased, which indirectly raises the air change rate.
Structural Characteristics of Modular Cleanrooms

Modular cleanrooms have better airtightness than traditional construction-type cleanrooms. For the same cleanliness class, the air change rate can be reduced by 5%–15%, which can meet the requirements while saving energy consumption.

4.Optimization Strategies for Air Change Rate of Modular Cleanrooms

Zoned Design
Divide areas by cleanliness class based on functions. Adopt high air change rate in core production zones and low rate in auxiliary zones to cut overall energy consumption.
Variable Frequency Control System
Equipped with FFU variable frequency technology, reduce rotation speed during non-production periods, lower air change rate by 30%–50% for remarkable energy-saving effect.
High-efficiency Filter Matching
Adopt H14/U15 grade high-efficiency filters, combined with top-supply and bottom-return air distribution, to reduce unnecessary air volume loss while meeting cleanliness requirements.