Cleanroom
Such rooms are commonly needed for scientific research and in industrial production for all nanoscale processes, such as semiconductor device manufacturing.
Cleanrooms typically come with a cleanliness level quantified by the number of particles per cubic meter at a predetermined molecule measure.
The ambient outdoor air in a typical urban area contains 35,000,000 particles for each cubic meter in the size range 0.5 μm and bigger, equivalent to an ISO 9 certified cleanroom.
[5] The majority of the integrated circuit manufacturing facilities in Silicon Valley were made by three companies: MicroAire, PureAire, and Key Plastics.
These competitors made laminar flow units, glove boxes, cleanrooms and air showers, along with the chemical tanks and benches used in the "wet process" building of integrated circuits.
These three companies were the pioneers of the use of Teflon for airguns, chemical pumps, scrubbers, water guns, and other devices needed for the production of integrated circuits.
[6][citation needed] A cleanroom is a necessity in the manufacturing of semiconductors, rechargeable batteries, pharmaceutical products, and any other field that is highly sensitive to environmental contamination.
What then is common to all cleanrooms is strict control of airborne particulates, possibly with secondary decontamination of air, surfaces, workers entering the room, implements, chemicals, and machinery.
Plastic sheets can be used to restrict air turbulence if the cleanroom design is of the laminar airflow type.
The selection of material for the construction of a cleanroom should not generate any particulates; hence, monolithic epoxy or polyurethane floor coating is preferred.
[12] Cleanrooms maintain particulate-free air through the use of either HEPA or ULPA filters employing laminar or turbulent airflow principles.
Laminar airflow systems are typically employed across 80% of a cleanroom ceiling to maintain constant air processing.
Stainless steel or other non shedding materials are used to construct laminar airflow filters and hoods to prevent excess particles entering the air.
US FDA and EU have laid down stringent guidelines and limits to ensure freedom from microbial contamination in pharmaceutical products.
[14] UV devices can be fitted into ceiling light fixtures and irradiate air, killing potentially infectious particulates, including 99.99 percent of airborne microbial and fungal contaminants.
[15] UV light has previously been used to clean surface contaminants in sterile environments such as hospital operating rooms.
Potential advantages of UV-based decontamination includes a reduced reliance on chemical disinfectants and the extension of HVAC filter life.
The opposite is done, e.g., in the case of high-level bio-laboratories that handle dangerous bacteria or viruses; those are always held at negative pressure, with the exhaust being passed through high-efficiency filters, and further sterilizing procedures.
Some cleanroom HVAC systems control the humidity to such low levels that extra equipment like air ionizers are required to prevent electrostatic discharge problems.
Low-level cleanrooms may only require special shoes, with completely smooth soles that do not track in dust or dirt.
This practice is common in many nuclear power plants, which operate as low-grade inverse pressure cleanrooms, as a whole.
The disadvantages are comparatively shorter HEPA fan filter life, worse particle counts than a recirculating cleanroom, and that it cannot accommodate air conditioning.
Aseptic practices are critical in environments where contamination control is paramount, particularly in the pharmaceutical, biotechnology, and medical device industries.
The Pharmaceutical Inspection Co-operation Scheme (PIC/S) classifies cleanrooms into four grades (A, B, C, and D) based on their cleanliness level, particularly the concentration of airborne particles and viable microorganisms.
In order to minimize the carrying of particulate by a person moving into the cleanroom, staff enter and leave through airlocks (sometimes including an air shower stage) and wear protective clothing such as hoods, face masks, gloves, boots, and coveralls.
Common materials such as paper, pencils, and fabrics made from natural fibers are often excluded because they shed particulates in use.
Cleaning chemicals used tend to involve sticky elements to trap dust, and may need a second step with light molecular weight solvents to clear.
Studying cleanroom microflora is of importance for microbiologists and quality control personnel to assess changes in trends.
Thus, even by international law, any probes we send to outer space must be sterile, and so to be handled in cleanroom conditions.
[citation needed] Since larger cleanrooms are very sensitive controlled environments upon which multibillion-dollar industries depend, sometimes they are even fitted with numerous seismic base isolation systems to prevent costly equipment malfunction.
