Workers and scientists perform some of the most sensitive production and research in cleanrooms, such as building microprocessors and studying minerals from outer space. Because of the necessity for a clean environment, cleanrooms are graded on an ISO scale to ensure workers follow and maintain strict levels of cleanliness. This maintenance includes wearing protective garments, called bunny suits, using high-powered air filters to remove particles from the air, and installing anti-static ion dischargers to prevent static electricity buildup from contaminating experiments or causing materials to fail.
In addition to these passive protective methods of maintaining cleanliness, workers also must concentrate on actively cleaning tools, materials, and equipment. To do so, workers cannot simply use standard cleaning supplies, but must employ specially designed and industrial strength cleanroom cleaning tools. There are many different methods for maintaining functioning cleanrooms and they are available in a range of forms.
Cleaning liquids and chemicals
For simple cleaning jobs in cleanrooms, such as wiping down counter tops and cleaning floors, a selection of chemicals is available that provides sterility and cleanliness. Two commonly used liquids are distilled water and isopropyl alcohol.
Although HEPA (high-efficiency particulate air) filters are common fixtures in cleanrooms, the daily activities and coming and going of workers in the facility can expel numerous air particles into the space, which eventually settle on equipment. In order to clean flat surfaces in cleanrooms, sticky rollers are available. Workers can clean countertops by running a roller across the flat surface so that it collects these particles. The worker can then wipe down the surface with a wiper (see below) to remove any excess residue.
Brooms and Brushes
Standard broomheads and brushes can retain bacteria and lose bristles during use, so special cleanroom versions usa polypropylene fibers in their heads. These bristles resist absorption of bacteria while remaining sturdy for cleaning up spills and collecting particles.
There are several special mops available for cleanroom needs. One version is the sticky-head mop, which features an adhesive head surface for collecting dry particles on a floor or walls. These are available in flat head or roller type extensions. Sponge mops are also quite common. They absorb bacteria, liquid and particles to be disposed of outside the cleanroom. Another mop variety is the non-woven layered mop head. This mop resembles a standard mop, but its threads are made from non-woven, spongy material to absorb spills and particles.
Shoe Cleaners Because workers walk on the floor both outside and inside cleanrooms, particles and bacteria may be picked up during standard, everyday activities. Shoe cleaners are available to help clean shoes and keep cleanroom floors free of detritus. One type resembles a golf shoe cleaner and appears as a small unit with an indent for placing one’s foot. A grip extension reaches up to waist level and the user can push a button to activate the automated brushes to clean the shoe. Another shoe cleaner, which also resembles a golf shoe cleaner, hermetically seals the shoe in plastic wrap, collecting fewer particles than standard rubber soles. In some cases, special elastic coverings are available for workers’ shoes so that they may be covered before entering the cleanroom.
Wipers and Squeegees
For applying rubbing alcohol or cleaning up small liquid spills, special wipe sheets called wipers are available. These are made of materials that can soak up liquids while not breaking apart and spreading debris in the area of the spill, such as cotton, nylon, polycellulose, polyester, and others. For larger spills, squeegees can clear liquid away quickly so an area can dry faster.
Dedicated cleanroom vacuum cleaners are designed to not expel carbon exhaust while performing at HEPA filter level. These types of filters can ensure that 99.999 percent of all particles 0.12 micrometers and larger are removed.