Clean by Design: How to Keep a Cleanroom Contaminate-Free

Creating controlled environments for long-term use

Clean by Design: How to Keep a Cleanroom Contaminate-Free

Despite its name, a cleanroom isn’t automatically clean. More properly called “controlled environments,” these spaces, used for everything from aerospace to pharmaceutical manufacturing, must be thoughtfully designed and impeccably maintained to ensure they keep contaminants out—and potentially hazardous materials in. Add garment protocols, specialty disinfectants, and operational requirements to the mix, and your controlled environment can become contaminated in the blink of an eye. From surfaces to sanitation, read on to learn the myriad factors that are necessary to keep your cleanroom clean.

What Qualifies as a Cleanroom?

To understand how to design and properly maintain a cleanroom, it’s important to understand that “cleanroom” is just a generic term; there is no single factor that defines one. While the International Standards Organization (ISO) is the most prevalent regulatory body in terms of assessing the cleanliness of controlled environments, it’s not the only organization that may impact the requirements for maintaining the environment.

Cleanrooms face a multitude of—and radically different—industry regulations that are dependent on the environment’s purpose, for example, whether you’re testing for the Ebola virus or manufacturing a microchip. Governing bodies exist for specific industries, and the rooms must remain in compliance with their industry’s respective protocols. While many cleanrooms are designed to achieve specific ISO classification levels, some will follow standards of other regulating bodies entirely due to the industry, and others will adhere to no regulations at all. Regardless of classification, many still follow stringent cleaning protocol. Thus, just as there are many classes of controlled environments and regulating bodies, there are as many sets of cleaning requirements to comply with maintaining the class level to which it was designed.

About that Design

Architectural planning may differ greatly for a cleanroom that needs to meet specific ISO criteria versus one that doesn’t. For example, when designing an ISO Class 2 controlled environment, designers need to minimize particle collection, which can be brought in from skin, air, water, or anything else entering the room. “When I’m designing, I think a lot about ledges and surfaces,” said Mike Grose, AIA, who designs controlled environments for architecture firm TreanorHL. “How do you design a window without ledges?” The answer is: carefully.

In a controlled environment, a window may have an obtuse angle to reduce particle collection or it will be pushed to the inside of the frame so the ledge is on the “dirty” side. Another consideration for windows: sealant. Every material in the room must be cleanable down to the caulk, and everything needs to be sealed and gasketed—lights, outlets, windows. Floors must be nonporous and as smooth as possible. (Sheet vinyl with welded seams is the industry standard.) Case work should be made of stainless steel so that it is cleanable but won’t deteriorate, as coating on wood will eventually break down.

Personal Protective Equipment

Even clothing poses a risk. In controlled environments designed to meet higher-level ISO requirements, one will typically first enter an airlocked vestibule. Here, street clothes are swapped for scrubs and clean shoes. In a second vestibule, garment protocol becomes more strict, with the addition of coveralls or a bunny suit, goggles, a mask, and hair net. “It’s a cascading level of cleanliness,” Grose said.

System Considerations

With cleanroom design, airflow is of utmost importance. Ducts need to be strategically placed to move air along parallel flow lines, as too much turbulence can cause particles to move. “While air coming in is minimized contaminate air, you have to also pull air out,” Grose said.

But air is complicated. It’s not just flow that is important. It’s also pressure, temperature, ventilation, humidity, filtration, condensation, and even static electricity. And the higher the ISO classification level, the more stringent the requirements will be in each of these categories. “It depends on what you’re doing in a room—does someone’s life depend on it or is it a microchip?” Grose said. These careful considerations will wind up affecting not only your architectural planning and day-to-day maintenance, but also everything from heating, ventilation, and air conditioning (HVAC) systems to rigorous cleaning protocol.

Keeping the Cleanroom Clean

While a cleanroom may have been designed to particular standards, if it’s not properly maintained, that status will cease to exist, bringing with it possibilities of chemical and radiological hazards, employee health and safety risks, encounters with mechanical irritants, or even the halting of production.

In addition to best practices like not having waste receptacles in the room and not introducing water to the space, strict protocol needs to exist for humans entering the room—one of the greatest threats to a sterile environment.

Not only do staff need to be trained, but so do cleaning crews. Essentially, the equipment, disinfectants, and cleaning team entering the controlled environment must be compatible with the required ISO rating, and because of this, it’s not a one-size-fits-all cleaning approach.

In some controlled environments, lab technicians handle maintenance. And in critical ISO Class 1 or 2 rooms, cleaning may be outsourced to a specialized company with trained experts. However, for an in-house approach, education is crucial. Staff need to be trained on the standards for that particular room’s ISO rating, proper gowning materials, cleaning techniques, personal hygiene, and much more.

When it comes to cleaning technique, crews must adopt slow and careful movements, as electrostatic discharge can even cause contamination. Surfaces must be wiped in a particular way, and even cleanroom cleaning equipment has its own cleaning protocol. Along the way, measurement and instrumentation will be helpful in mitigating contamination risk as is developing protocol for major decontamination after maintenance work.

And if that weren’t enough, even equipment and solvents pose threats. Disinfectants must be carefully manufactured, packaged, and transported so as not to transmit unwanted matter. And in instances of heavy debris, a detergent must be used first—yet sometimes the detergent and solvent counteract, neutralizing the active ingredients.

Contaminants in Cleanrooms

From varying classifications and regulatory bodies to room purpose and resources, keeping a cleanroom compliant is no easy feat. “Cleanrooms have a lot of contaminants—they’re not perfect,” said Grose. “And the bigger the room, the harder it is to control.”

Despite the regulations and rigorous protocol, there is a constant contaminant threat from personnel to equipment and materials. If not designed or maintained properly, your controlled environment can put the company at risk in many ways from requiring recertification or worse, having deadly contaminants infiltrate outside spaces.

But when the equipment and solvents themselves need to be manufactured in a controlled environment and even those can counteract, we can’t help but wonder: Can a cleanroom ever be truly clean?

Grose thinks so. “A controlled environment, if cleaned well and designed well, could last 50 years,” he said. “I like that challenge of all the different requirements—regulatory, the built environment, existing additions—to make all of that fit into a single space.” And a clean one at that.


Posted On October 8, 2018

Amy Phare

Amy Phare is a writer and editor for the architecture, engineering, and construction industry with 20 years of experience in professional services and nonprofit leadership. She can be reached at

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Clean by Design: How to Keep a Cleanroom Contaminate-Free
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