Cleanrooms are special facilities dedicated to the manufacture or research of materials that cannot come into contact with air particles, skin flakes, or other detritus due to their high sensitivity or need to remain sterile. Microprocessors are such delicate pieces of equipment that the smallest air particle might cause the entire machine to fail. Additionally, research on biochemicals requires a clean environment so results are not skewed by the introduction of foreign elements.
In order to work in a cleanroom, human workers and scientists require a wide array of tools, equipment and garments to protect their items from outside interference. Some of these items are specifically made for cleanroom use, while others are clean versions of everyday items.
Special cleanroom suits, sometimes called “bunny suits,” are necessary to cover workers, because skin, hair and breath particles account for the dirtiest substances introduced into the cleanroom environment. Depending on the level of cleanliness designated by the cleanroom’s ISO rating, different levels of protection need be worn. For instance, in a higher cleanliness room, such as a cleanroom where microprocessors are produced, a full suit in addition to a hair covering, goggles, face mask and gloves would need to be worn. In a less clean facility, the face mask and goggles might not be necessary.
HEPA Filter A high efficiency particulate air (HEPA) filter is a precision high volume air filter capable of cleaning air of all particles 0.3 micrometers in diameter or larger. HEPA filters work to clean air with microfibrous membrane materials. These microfibers are able to cling to or block air particles that filter through the device in one of three ways:
Interception: HEPA air filters feature airflow designs that are aimed in a specific way to capture air particles. For interception, this airflow design is intended to force the tiny microfibrous threads to cling to air particles as they flow past.
Impaction: In impaction, the airflow attempts to force small particles to directly impact the fibers.
Diffusion: Diffusion is the last result of air filtration. Airflow swishes around in circular and other patterns, attempting to break up the particles or send them on labyrinthine trips through the microfibers, increasing the chances that the particles with be intercepted by the fibers or that the particles will impact the fibers themselves.
Pass-Thru Doors and Windows:
In order to transport items, materials and equipment from outside the cleanroom into the interior, pass-thru doors and windows are used. These are air-tight transition chamber. There are hermetically sealed doors on either side of a small chamber area. To pass an item through, a worker opens the door leading to the exterior, puts the item in the chamber, and then closes it. A worker on the other side opens the door leading to the exterior and removes the item. This way, both doors aren’t open at the same time, which would allow non-filtered, dirty air to enter the cleanroom and sully equipment.
Air showers are necessary to clean dirt and skin particles that may have rubbed off on workers as they changed into their bunny suits. Because biological entities, including human beings, shed skin flakes, drop hair particles, exhale bacteria, and secrete grease and oils, there are a lot of unwanted particles that can be transmitted to a bunny suit while changing. An air shower provides a high powered blast of clean, filtered air, which will remove a great deal of the dirty particles on a bunny suit. These showers exist in pass-thru air locks or as separate chambers in the changing room.
Because much science research is performed in cleanrooms, clean labware is a primary tool of many cleanroom workers. Additionally, because clean labware often handles biochemicals or otherwise toxic materials, it is important that it be washed and disposed of correctly after use.
Clean Tools and Equipment:
There are many other items that need to be “clean” in order to enter a cleanroom. For instance, clean pencils and paper are available to cleanroom workers in order to avoid pencil and graphite flakes getting into the air and causing problems with other equipment. Trays and other carrying equipment must be made of nonporous material to prevent particles on the equipment from entering the cleanroom. For tool and equipment cleaning, clean wipes are generally available in cleanrooms to sterilize and wipe down equipment that might have come in contact with undesirable particles.