What is not allowed in a cleanroom?

what is not allowed in a cleanroom

Cleanrooms are just that: clean. Therefore, there are strict requirements around what is allowed in a cleanroom and what is not. While exact guidelines might change in different cleanrooms, the following are considered general guidelines and best practices about what should not be allowed in a cleanroom.

Street Clothes

Your street clothes carry billions of particles on them from your home, your car, the Starbucks you stopped at this morning, the woman who brushed against you in the parking lot, and everywhere in between. It’s important that you don’t expose those particles to the cleanroom environment.

Exposed Skin

Skin is a major producer of particles. Even a square inch of exposed skin can produce thousands of particles in a matter of seconds.

skin flakes

Every minute, our body sheds about 40,000 skin cells. Even when stationary, we can generate upwards of 100,000 particles that are 0.3 microns or larger. If we start moving, that number increases to more than 5,000,000.

Fast Movement

Quick movement can generate a lot of particles! It tends to create more friction, which causes us to shed particles. If you’re working in a laboratory setting, quick movement can also prove a danger to the materials. So cleanroom guidelines typically stipulate that there should be no running or moving quickly in a cleanroom.

Eating & Drinking

Part of proper gowning protocol includes a face mask, because your mouth can produce a lot of particles. If COVID taught us anything, it’s that face masks are to keep our germs to ourselves and in our mouths. The same principle applies in cleanrooms. So to eat or drink, you would need to remove a part of your gowning – your mask – and risk literally spitting out particles. Not to mention that each bite of food can create particles. So best practice is to keep all pieces of personal protective equipment (PPE) in place and properly secured.


This one might initially sound controversial, but is really very practical. Any type of powder or liquid can be smudged and come off. Even those smudges can be enough to cause contamination. So this is not an outdated rule to keep women out of the cleanroom – it’s a practical consideration of unnecessary contaminants in a cleanroom. But these regulations could be different from cleanroom to cleanroom and also depends on their ISO classification.

Paper & Fabric Towels

Paper and fabric towels are traps for particles. So anytime you use a paper or fabric towel to wipe something down, you’re really just smearing particles from the towel onto the surface. Additionally, when paper is torn, it creates and sheds particles. But there are specific types of paper that are allowed in the cleanroom, so you can still have paper in the cleanroom – just not paper towels.

Sitting Or Leaning On Equipment

Anytime you sit or lean on equipment, you run the risk of passing particles onto it. But this is also just, in general, best practice of working with expensive, highly calibrated equipment and machinery. Knocking them out of alignment by leaning a hip against them can set the workday back by several hours and cause a huge lag in production.

Wearing Torn Garments

Torn garments are a surefire way for particles from your street clothes and skin to make their way into your cleanroom. Gowns, booties, and other PPE should be removed directly from a sealed, sterilized bag, so if it comes with holes in the garment, that is cause for concern about its sterility. If you remove a torn garment from a bag, you should dispose of it and check the other PPE from that shipment for similar deformities.


Yup, that’s right. Your fingerprints are not allowed in a cleanroom. Depending on the use of your cleanroom, fingerprints can contaminate surfaces and cause issues. So no fingerprints in the cleanroom! Typically, there will be approved gloves as part of your gowning to prevent this from being a problem.

Making The Most Of Your Cleanroom

So what are the regulations in your cleanroom? Do you follow industry guidelines and best practices?

No matter what industry you operate in, there are sets of best practices and guidelines for your ISO classification. They can be arduous and difficult to keep track of, but the good news is that we’re doing it for you!

In our Knowledge Center, we have easy to digest information about what are the current standards and best practices in your industry. It’s an incredible wealth of information and frequently updated – and it’s all free. Just create your free account today to get started learning, so you can be the smartest in the room and have all the answers.

No obligations, no gimmicks – just plenty of information.

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