01 Jan Cleanroom Fan Filter Units: What You Need to Know

The particles that cleanrooms prevent from entering may be invisible to the naked eye, but their effect on many manufacturing processes isn’t. Recalls, product damage, and lawsuits are all very real possibilities for companies that create sensitive and essential products, whether that be for aerospace, electronics, pharmaceuticals, or other applications. Cleanrooms depend on pristine air quality to make sure that products stay safe and effective, and fan filter units (FFUs) are the technology that makes this possible. In this article, we’ll cover what cleanroom fan filter units are, how to choose the right FFUs for your cleanroom, and more.

If you’d like to talk to an expert directly about what you need, consider reaching out to us here!

What are Cleanroom Fan Filter Units?

Cleanroom fan filter units, also known as FFUs, are motorized, self-contained devices that generate clean air for cleanrooms and other controlled environments. Each unit has a fan and a high-efficiency particulate air (HEPA) or ultra-low penetration air (ULPA) filter. They are typically installed in a space above the ceiling of a cleanroom, called the plenum, where they push air through the filter and into the room.

HEPA vs. ULPA Filters in Cleanroom FFUs

When selecting a fan filter unit, one of the most important considerations is the type of filter it uses. The choice between HEPA and ULPA filters always comes down to the specific needs of your cleanroom or controlled environment:

• HEPA Filters: These are the most common choice for cleanrooms. They remove particles at 0.3 micrometers at 99.97% efficiency. This will generally be sufficient for less strict cleanrooms, such as ISO 7 or ISO 8.
• ULPA Filters: These filters, on the other hand, are better for stricter classifications like ISO 5 and above. ULPA filters are more expensive, but are better at trapping smaller particles. They can remove 99.99% of contaminants at 0.12 micrometers.

Some stages of semiconductor or pharmaceutical manufacturing may require ULPA filters, while for most other uses HEPA filters will be sufficient.

Cleanroom Fan Filter Unit Options

Cleanroom FFUs can come with a variety of different features. Here are a few common options to consider:

• Size: Common sizes include 2’x4’, 2’x2’, and 4’x4’. Larger units cover more area, while smaller units may be better for small rooms or targeting certain spaces.
• Room-Side Replaceable Filters (RSR): These FFUs are more expensive, but they allow filters to be replaced without removing the whole unit, so these may be helpful in cleanrooms where filters need to be replaced often.
• Remote Speed Control: With this feature, you can adjust the fan speed using a device or other controls.
• Voltage Choices: Units are typically available in 115V, 230V, and 277V.
• Indicator Lights: Some units have lights to signal whether a filter needs to be changed, or whether the motor is working, via colored lights.

Choosing the Right Fan Filter Unit for Your Cleanroom

Before selecting FFUs, you must first make sure that you fully understand your cleanroom’s requirements. Here are a few factors to keep in mind:

• Cleanroom Classification: Higher-class cleanrooms, such as ISO 5, require more frequent air changes, and will certainly require a higher density of FFUs.
• Air Changes Per Hour (ACH): Higher classifications and other factors may require a cleanroom to have higher ACH. And to reach higher ACH, you will inevitably need more FFUs.
• Filter Type: As we’ve discussed already, make sure the filter type will get your cleanroom to the desired classification. For a general heuristic, use HEPA filters for general applications or ULPA for the strictest spaces.

The Bottom Line

In short, fan filter units are a must-have for keeping modern manufacturing spaces clean and controlled. The exact type of FFU, whether HEPA or ULPA, along with the specific features of the units, will depend on your cleanroom requirements and other industry standards.

Interested in designing or upgrading cleanrooms? Reach out to the experts at Allied Cleanrooms for a custom quote today.