When There’s No Room for a Cleanroom, Build a Clean Booth Instead

How one optical equipment manufacturer achieved ISO Class 5 cleanliness without expanding its existing facility

A few months ago, one of our customers approached us with a challenge that many manufacturers eventually face.

Their production line was already operating inside an ISO Class 6 cleanroom, and everything was running smoothly. Then a new optical assembly project came along — one that required an ISO Class 5 environment.

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The problem wasn’t achieving a cleaner environment.

The problem was finding somewhere to put it.

Their existing cleanroom had already reached its capacity. Expanding the facility would have required major construction, production interruptions, and a significant investment. For a relatively small assembly area, it simply wasn’t practical.

Instead of building another cleanroom, they built a clean booth inside the one they already had.

It turned out to be exactly what they needed.

What Exactly Is a Clean Booth?

If you’ve never worked with one before, the easiest way to think of a clean booth is as a cleanroom inside another room.

Rather than controlling the air quality of an entire production area, a clean booth creates a localized clean environment only where it’s actually needed.

Most clean booths use a stainless steel frame, transparent side panels, and Fan Filter Units (FFUs) that supply HEPA-filtered vertical laminar airflow. Depending on the design, they can achieve cleanliness levels from ISO Class 5 to ISO Class 7.

Because they’re modular, clean booths can usually be installed within days instead of months. They’re also easier to relocate or expand if production requirements change later.

For manufacturers that only need a few critical workstations to meet stricter cleanliness standards, this approach is often much more practical than constructing another full cleanroom.

Why Localized Cleanliness Makes Sense

Not every part of a production process needs the same level of contamination control.

In pharmaceutical manufacturing, electronics assembly, medical devices, or precision optics, only certain operations are truly critical. Assembly, inspection, sampling, or testing stations often require much cleaner conditions than surrounding production areas.

Building an entire ISO Class 5 cleanroom just to protect one workstation is similar to cooling an entire warehouse because one employee needs air conditioning. It works — but it’s rarely the most efficient solution.

A clean booth solves this problem by creating a dedicated high-cleanliness zone exactly where it’s needed, while allowing the surrounding facility to continue operating under its existing classification.

The Project

Our customer manufactures high-precision optical components used in advanced imaging systems.

Their existing ISO Class 6 cleanroom had been operating successfully for years. However, a new production process introduced much stricter contamination requirements, making ISO Class 5 cleanliness essential.

The first option they considered was expanding the cleanroom.

After reviewing the layout, it quickly became clear that there simply wasn’t enough usable space. Even if expansion had been possible, the construction time, production disruption, and overall investment would have been difficult to justify.

Instead, we designed a modular clean booth that could be installed directly inside the existing cleanroom.

The booth created an independent ISO Class 5 environment while making full use of the customer’s current facility.

To meet their production requirements, the booth included:

• 304 stainless steel construction for durability and easy cleaning
• High-efficiency HEPA filtration (99.99% at 0.3 μm)
• Vertical laminar airflow with adjustable air velocity
• Transparent acrylic side panels for visibility and contamination control
• A modular structure that can be relocated or expanded in the future

Most importantly, the customer achieved the required cleanliness level without changing the building itself or interrupting ongoing production.

Why They Chose a Clean Booth

Traditional CleanroomModular Clean BoothMonths to constructInstalled within daysHigh construction costMuch lower investmentPermanent structureModular and expandableRequires dedicated spaceFits inside existing facilitiesMajor production disruptionMinimal interruptionDifficult to modify laterEasy to relocate or upgrade

For this project, the decision wasn’t about choosing between two technologies.

It was about choosing the solution that made the most practical sense.

Where Clean Booths Are Commonly Used

Although this project involved precision optical manufacturing, the same approach is widely used across many industries.

We’ve seen clean booths successfully applied in:

• Pharmaceutical weighing and sampling areas
• Medical device assembly
• Biotechnology laboratories
• Electronics and semiconductor production
• Cosmetic and food manufacturing

Whenever only part of a production process requires higher cleanliness, a modular clean booth can often deliver the required performance without the cost and complexity of building another cleanroom.

What We’ve Learned

Projects like this remind us that cleaner doesn’t always have to mean bigger.

Many manufacturers assume that achieving a higher cleanliness level requires building a new cleanroom. In reality, that’s not always the case.

Sometimes the most effective solution is simply creating a cleaner environment exactly where it’s needed.

That’s the idea behind modular clean booths — and it’s why more manufacturers are adopting them as production requirements continue to evolve.

Further Reading

If you’re considering adding an ISO Class 5 work area inside an existing production facility, we’ve put together more information about our modular clean booth solutions below.

👉 ISO 5 Clean Booth with FFU | 304 Stainless Steel Softwall Cleanroom

You can also explore our complete range of modular cleanroom systems at:

👉 www.prefabcleanroom.com