The Importance of Contamination Control
Maintaining a cleanroom requires constant monitoring to preserve a sterile environment. Depending on your specific requirements, you may need continuous control for environmental factors like humidity, temperature, and particle counts. Contamination control is a top priority for industries such as pharmaceutical compounding, microelectronics, and specialized pharmacies. Though achieving it efficiently can be challenging due to contaminants from personnel and equipment, which must be actively mitigated by your airflow design.
Understanding Air Changes Per Hour (ACH)
Understanding Air Changes Per Hour (ACH) and properly using Fan Filter Units (FFUs) are essential steps to achieving and maintaining strict ISO classifications. It’s also important for reducing utility costs and operational downtimes. The ACH rate dictates how often the total volume of air within the room is completely replaced. If you get the ACH calculations wrong, you risk severe consequences. If you overdesign, it leads to an excessive amount of FFUs, which increases cleanroom power consumption and heat load, causing huge energy bills. Conversely, underdesigning risks compliance issues or product failure.
The Role of Fan Filter Units (FFUs)
Regulatory compliance in any cleanroom depends ultimately on the constant replacement of contaminated air with clean air. The Fan Filter Unit is essential for this function. An FFU is a filtered laminar flow diffuser with its own integrated motor, capable of pushing air through the dense H14 HEPA filters (which remove 99.995% of particles at 0.3 microns) directly into the cleanroom without depending completely on a central HVAC system. FFUs offer great modular flexibility and eliminate the need for frequent system rebalancing.
Calculating Your Target Air Changes Per Hour (ACH)
The ACH Formula is calculated as:
ACH = (CFM x 60) / Room Volume.
- CFM: The volume of air in CFM (cubic feet per minute) delivered into the room by FFUs.
- Multiplying the CFM by 60 gives you cubic feet of air your device moves per hour.
- Divide that number by the total Room Volume (in cubic feet).
After using the formula, your findings will tell you how many times per hour the device moves the total volume of the room. This is your Air changes per hour (ACH).
ICS FFU Specifications and Airflow Adjustment
ICS standard FFUs deliver roughly 500 CFM (specifically 580 - 706 CFM depending on the setting). To accommodate varying levels of cleanroom requirements, the ICS Fan Filter Unit is equipped with a built-in 3-level rotary switch. This allows facility managers to make airflow adjustments to fine-tune the Air Changes Per Hour (ACH) and maintain the cleanroom’s compliance without relying on complex external control systems.
*ICS FFU with 3-level rotary switch*
Electrical Configurations and Power Load
In determining the amount of FFUs necessary to meet your ACH target, it's necessary to factor in the facility’s electrical capacity. Electrical grids that are undersized can lead to operational downtime, so planning ahead is important. ICS FFUs are available in two primary configurations.
- 120V Model: Operates a 150W and draws 1.4 Amps
- 220C Model: Operations at 135W and draws 0.65 Amps.
Factoring these specifications into your design ensures your facility can support the required volume of units safely. This allows you to maintain the laminar flow needed to hit your target ISO classifications.
Conclusion: Achieving ISO Compliance with Confidence
Navigating cleanroom standards and environmental controls doesn’t have to be an overwhelming process. By using the given formula to calculate your target ACH and finding the amount of FFUs necessary for your cleanroom, you can protect your processes without increasing your energy costs. The key is balancing regulatory requirements with operational efficiency. Instant cleanrooms provide the reliable devices necessary to hit those targets. With our FFUs, facility managers have the tools necessary for maintaining airflow and maintaining ISO classifications. Whether you are upgrading your existing layout or starting new, the ICS team is ready to help you verify your ACH calculations and find the ideal FFU layout for your facility.
Sources:
"Air Changes Per Hour (ACH) in Cleanrooms: The Most Misunderstood Metric (and How to Get It Right)." Enershares, enershares.com/air-changes-per-hour-ach-in-cleanrooms-the-most-misunderstood-metric-and-how-to-get-it-right/.
American Cleanroom Systems. "All About Cleanroom HEPA Fan Filter Units." American Cleanroom Systems, www.americancleanrooms.com/all-about-cleanroom-hepa-fan-filter-units/.
"How Many Air Changes per Hour Are Required for the Different Cleanroom Classifications?" Cleanroom.net, cleanroom.net/faqs/how-many-air-changes-per-hour-are-required-for-the-different-cleanroom-classifications/.
"How to Calculate Air Changes Per Hour." Camfil, 22 Oct. 2021, cleanair.camfil.us/2021/10/22/how-to-calculate-air-changes-per-hour/.