Air Velocity & Air Changes Per Hour Measurement
Maintaining superior indoor air quality is a cornerstone of cleanroom and controlled environment performance. At SUN CleanAir Systems, Vasai, we specialize in precision-engineered cleanroom solutions, and a key part of validating their performance involves the measurement of air velocity and Air Changes per Hour (ACH). But why are these measurements so important?
What is Air Velocity?
Air velocity is the speed at which air moves through a given space, typically measured in meters per second (m/s) or feet per minute (fpm). In cleanrooms, especially laminar flow units or unidirectional airflow systems, air velocity ensures contaminants are continuously pushed away from critical zones.
- Ideal air velocities vary by cleanroom class.
- For example, ISO Class 5 clean zones often require a uniform airflow of 0.45 m/s ± 20%.
How Is It Measured?
Using calibrated instruments like thermal anemometers or vane-type anemometers, our engineers at SUN CleanAir Systems perform multiple point measurements at filter face level or across designated sections of a clean zone.
What Are Air Changes per Hour (ACH)?
ACH refers to how many times the total air volume in a space is replaced with fresh filtered air in one hour. It is a critical performance indicator in cleanroom HVAC systems.
- A higher ACH means more frequent air turnover, reducing the chance for contamination.
- Cleanrooms typically range from 20 to over 600 ACH depending on ISO classification and process needs.
ACH = (Total Supply Air Volume per Hour) / (Room Volume)
Example: A room with 1,200 CFM airflow and 10,000 cu. ft. of volume has 7.2 ACH.
Why Are These Measurements Crucial?
- They ensure compliance with ISO 14644, GMP, and FDA regulations.
- Validate the effectiveness of HEPA/ULPA filters and air handling systems.
- Ensure laminar flow patterns and pressure cascades are maintained.
- Reduce contamination risk and safeguard product integrity.
SUN CleanAir Systems' Expertise
We offer on-site testing, validation, and certification services that include:
- Air velocity mapping
- ACH validation reports
- Smoke visualization tests
- HEPA filter leak testing
- Room pressurization checks
Final Thoughts
Accurate air velocity and ACH measurements are not just compliance checkboxes—they are the pulse of a cleanroom's health. At SUN CleanAir Systems, we don’t just measure performance—we engineer it.