While cleanrooms are supposed to be the quintessential sterile space, there is no guarantee of a perfect, contaminant free cleanroom. However risk of contamination can be minimised by adhering to proper protocols including room pressure requirements, proper gowning procedures. While you may be well aware of some of the items on our list, others will likely surprise you.
Here are some of the most common sources of cleanroom contamination:
From operators
Your cleanroom personnel are the single largest source of contamination in cleanrooms with studies showing that they account for almost 80% of all particles found in cleanroom inspections. These contaminants are in the form of dead skin, hair, oil, fibres from clothing, as well as particles from lotions, deodorants, cosmetics and perfumes.
From exposed communication devices
Most facilities ban the use of handheld devices inside cleanrooms. If walkie talkies or cell phones must be brought inside the cleanroom, it must always be carried on the person of the operator but in a special sterile pack. Using these avoids any form of contamination to the cleanroom.
From incorrect flooring
If your cleanroom requires a static control environment, an ESD floor must be installed. All equipment used in cleanrooms myst be properly grounded to the floor or you risk contamination especially when ESD carts, chairs and shoe covers are in use.
From furniture and equipment
Any time you deal with moving pieces, it can create electrostatic discharge or release contaminants. It is absolutely vital for operators to keep furniture movement to an absolute minimum when working inside a cleanroom. Even something as minor as moving or adjusting the height of a chair can cause contamination.
From uncovered electrical outlets
If electrical outlets are not correctly sealed, they are an open invitation for every insect in the vicinity. Insects can crawl through and contaminate the cleanroom.
From incorrect use of face masks and gowns
Contamination can be caused by something as simple as an operator wearing a face mask inside out. The same goes for coveralls and gowns. When gowning up, no part of the coverall or gown should touch the floor or walls. If they do, there is risk of the contaminants and particulates entering the cleanroom on the clothing.
From tacky mats
Tacky mats are perfect for picking up contaminants from the bottom of shoe, but they are also a tripping hazard. Tacky mats should be securely attached to the floor. They should also be the right size so ‘both’ feet in step are covered by their surface area.
From bringing equipment and supplies into the cleanroom
If you need to frequently bring equipment and supplies into the cleanroom then investing in a pass box is vital. You also need to make sure the containers in which raw materials and supplies are brought in are completely free of contaminants.
From damaged HEPA filters
HEPA filters sometimes get damaged as a result of enthusiastically aggressive cleaning. Check often to ensure yours are intact.
By understanding the origins of these common contaminants you can minimise risk to your sterile cleanroom environment and processes by reducing contamination at source.
