The Role of Filtration in Cleanroom Air Quality

*This post is part of a much larger pillar blog: The Complete Guide to Controlled Environments.

Introduction

An extremely high level of clean room air quality is the defining characteristic of what makes a cleanroom, a cleanroom. A key to achieving this high level of quality is excellent filtration.

In this article, we’ll break down how filtration works, the types of filters used, and why proper maintenance of these filters is essential for keeping cleanrooms free of contaminants.

Understanding Cleanroom Air Quality

To start, let’s talk about why cleanroom air quality is so important if you’re not already familiar.

Cleanroom air quality isn’t just about looking clean—it’s about meeting strict regulatory standards that define acceptable particle levels.

What are some of these regulatory standards, though?

Regulatory Standards for Cleanrooms

Cleanroom standards (also known as classifications) are based on how many particles are allowed per cubic meter of air.

The ISO 14644-1 standard categorizes cleanrooms from ISO 1 (the cleanest) to ISO 9 (less stringent but still controlled). Industries such as pharmaceuticals and microelectronics often require ISO 5 or cleaner environments.

Check out this cleanroom classification chart for more details:

Let’s look quickly at what contaminates these regulations are meant to prevent.

Common Contaminants in Cleanrooms

Cleanrooms battle contaminants from multiple sources. Below, we’ve listed the three main ones, but of course there are always other contaminates to be on the lookout for.

• Airborne Particles – Dust, fibers, and microscopic debris
• Microorganisms – Bacteria, fungi, and viruses
• Chemical Vapors – Gases from equipment or cleaning agents

 

If you want more detailed information on these contaminates, as well as other cleanroom challenges that exist, check out this article.

Next up, we’ll go into how exactly filtration works inside a cleanroom.

How Filtration Works in Cleanrooms

Filtration is the first and last line of defense in keeping air quality within specifications. 

It operates through a multi-stage process designed to trap particles before they reach critical areas inside of the cleanroom, such as equipment or materials.

Types of Cleanroom Filters

When looking at filters that are most commonly used inside of a cleanroom, we have pre-filters, HEPA filters, ULPA filters, and even activated Carbon filters.

Pre-Filters: The First Line of Defense

Pre-filters capture larger particles, preventing them from overloading finer filters downstream. 

These are essential for extending the life of HEPA and ULPA filters.

HEPA Filters: The Industry Standard

HEPA filters capture 99.97% of particles as small as 0.3 microns. They are the go-to solution for most cleanrooms, ensuring that airborne contaminants don’t compromise operations.

ULPA Filters: Taking Filtration to the Next Level

For industries requiring ultra-clean environments, ULPA filters remove 99.999% of particles down to 0.12 microns. These are more common the lower ISO spec you go. For example, semiconductor and aerospace industries often use ULPA filters for the highest level of air purity.

Advanced Carbon Filters: Eliminating Chemical Contaminants

In some applications, removing chemical vapors is as crucial as eliminating particles. Activated carbon filters absorb harmful gases and odors that can interfere with sensitive processes.

After the initial install of the filters, how often should you perform maintenance or replace the filters in your room?

Maintaining and Replacing Cleanroom Filters

Proper maintenance is the key to keeping filtration systems effective. Let’s look at how often you need to replace filters, and what the big signs of a failing filter are.

• When to Replace Filters – HEPA filters typically last 1-3 years, but high-use cleanrooms may require more frequent replacements. This is heavily dependent on what brand of filters you choose for your room, and what ISO classification you’re trying to meet.
• Signs of a Failing Filter – Increased particle counts, unusual airflow patterns, or changes in differential pressure indicate a filter needs replacing. In order to protect the integrity of your room, you need to be replacing them ASAP when you notice an issue.

 

The Impact of Poor Filtration on Cleanroom Performance

Failing to maintain filtration can lead to:

• Product contamination, resulting in costly recalls
• Regulatory violations and shutdowns
• Increased risk of microbial growth in pharmaceutical or biotech cleanrooms

 

Like we mentioned in the section above, if you notice any of the previously mentioned signs of a failing filter, replace it as soon as you can to mitigate the potential negative consequences.

What are some of the innovations our team is seeing in filtration?

Innovations in Cleanroom Filtration

Technology is advancing filtration capabilities. Some of these technologies include the introduction of nanofiber filters for better particulate capture, and smart filtration systems.

• Nanofiber Filters – Capture even smaller particles with greater efficiency. In these filters, Nanofibers act as a thin layer above an existing filter type (HEPA or ULPA)
• Smart Filtration Systems – Monitor air quality in real-time, alerting operators when maintenance is needed. Advanced controls systems are becoming increasingly popular for all aspects of a cleanroom or dryroom

 

Check out this video highlighting a complete controls system we did for a client in the dental manufacturing industry last year.

Conclusion

Filtration is the backbone of cleanroom air quality, preventing contaminants from compromising sensitive operations. By using the right filters, maintaining them properly, and staying ahead of technological advancements, cleanrooms can achieve the highest standards of air purity.

Need to upgrade your cleanroom’s filtration system? Contact us.