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'{{about|the manufacturing or research environment|the method used to avoid copyright infringement|Clean room design|the software engineering methodology|Cleanroom software engineering}} [[File:Clean room.jpg|thumb|right|Cleanroom used for the production of microsystems. The yellow lighting is necessary for [[photolithography]], to prevent unwanted exposure of [[photoresist]] to light of shorter wavelengths.]] [[File:Cleanroom outside.jpg|thumb|right|Cleanroom from outside]] [[File:Cleanroom entrance.jpg|thumb|right|Entrance to a cleanroom with no air shower]] [[File:Cleanroom1.jpg|thumb|right|Cleanroom for [[microelectronics]] manufacturing with [[fan filter unit]]s installed in the ceiling grid]] [[File:Cleanroom-Cabin.JPG|thumb|right|Cleanroom cabin for precision measuring tools]] [[File:Cleanroom Garment2.JPG|thumb|Typical cleanroom head garment]] A '''cleanroom''' or '''clean room''' is an environment, typically used in [[manufacturing]], including of pharmaceutical products or scientific research, with a low level of environmental [[pollutant]]s such as dust, airborne [[microbes]], [[Particulate|aerosol]] particles, and chemical vapors. More accurately, a cleanroom has a '''controlled''' level of contamination that is specified by the number of particles per cubic meter at a specified particle size. To give perspective, the ambient air outside in a typical urban environment contains 35,000,000 particles per cubic meter in the size range 0.5&nbsp;[[Micrometre|μm]] and larger in diameter, corresponding to an [[International Organization for Standardization|ISO]] 9 cleanroom, while an ISO 1 cleanroom allows no particles in that size range and only 12 particles per cubic meter of 0.3&nbsp;μm and smaller. ==History== The modern cleanroom was invented by American [[physicist]] [[Willis Whitfield]].<ref name=nkwes>{{cite news|first=William|last=Yardley|title=Willis Whitfield, Clean Room Inventor, Dies at 92 |url=http://www.nytimes.com/2012/12/05/business/willis-whitfield-clean-room-inventor-dies-at-92.html |work=[[New York Times]] |date=2012-12-04 |accessdate=2013-06-22}}</ref> An employee of the Sandia National Laboratories, Whitfield created the initial plans for the cleanroom in 1960.<ref name=nkwes/> Prior to Whitfield's invention, earlier cleanrooms often had problems with particles and unpredictable [[airflow]]s. Whitfield designed his cleanroom with a constant, highly filtered air flow to flush out impurities.<ref name=nkwes/> Within a few years of its invention in the 1960s, Whitfield's modern cleanroom had generated more than $50 billion in sales worldwide.<ref name=kwes>{{cite news|first=|last=|title=Sandia physicist, cleanroom inventor dies at 92 |url=http://www.kwes.com/story/20187574/sandia-physicist-cleanroom-inventor-dies-at-92 |work=[[KWES-TV|KWES]] |publisher=[[Associated Press]] |date=2012-11-26 |accessdate=2012-12-03}}</ref> ==Overview== Cleanrooms can be very large. Entire manufacturing facilities can be contained within a cleanroom with factory floors covering thousands of square meters. They are used extensively in [[Fabrication (semiconductor)|semiconductor manufacturing]], [[biotechnology]], the [[life sciences]], and other fields that are very sensitive to environmental contamination. The air entering a cleanroom from outside is [[filter (air)|filter]]ed to exclude dust, and the air inside is constantly recirculated through high-efficiency particulate air ([[HEPA]]) and/or ultra-low particulate air ([[ULPA]]) filters to remove internally generated contaminants. Staff enter and leave through [[airlock]]s (sometimes including an [[air shower (room)|air shower]] stage), and wear protective clothing such as hoods, face masks, gloves, boots, and coveralls. Equipment inside the cleanroom is designed to generate minimal air contamination. Only special [[mop]]s and [[bucket]]s are used. Cleanroom furniture is designed to produce a minimum of particles and to be easy to clean. Common materials such as [[paper]], [[pencil]]s, and [[Textile|fabric]]s made from natural fibers are often excluded, and alternatives used. Cleanrooms are not [[sterilization (microbiology)|sterile]] (i.e., free of uncontrolled microbes);<ref>[http://www.nytimes.com/2007/10/09/science/09clea.html?ref=science In NASA’s Sterile Areas, Plenty of Robust Bacteria] New York Times, 9. October 2007</ref> only airborne particles are controlled. Particle levels are usually tested using a [[particle counter]] and microorganisms detected and counted through environmental monitoring methods.<ref>{{Cite journal|author=Sandle, T |title=Application of quality risk management to set viable environmental monitoring frequencies in biotechnology processing and support areas|journal=[[PDA (journal)|PDA J Pharm Sci Technol]] |volume=66 |issue=6 |pages=560–79|date=November 2012 |doi=10.5731/pdajpst.2012.00891}}</ref><ref name="Sandle, T 392–403">{{Cite journal|author=Sandle, T |title=A review of cleanroom microflora: types, trends, and patterns|journal=[[PDA (journal)|PDA J Pharm Sci Technol]] |volume=65 |issue=4 |pages=392–403|date=November 2011 |doi=10.5731/pdajpst.2011.00765}}</ref> Some cleanrooms are kept at a [[positive pressure]] so if any leaks occur, air leaks out of the chamber instead of unfiltered air coming in. Some cleanroom [[HVAC]] systems control the [[humidity]] to low levels, such that extra equipment ("ionizers") is necessary 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. However, for safety reasons, shoe soles must not create slipping hazards. Access to a cleanroom is usually restricted to those wearing a [[cleanroom suit]]. In cleanrooms in which the standards of air contamination are less rigorous, the entrance to the cleanroom may not have an air shower. An anteroom (known as a "gray room") is used to put on clean-room clothing. Some manufacturing facilities do not use fully classified cleanrooms, but use some cleanroom practices to maintain their contamination requirements. == Air flow principles == {|class="centered" |- style="vertical-align:top" |[[File:Turbulenter Reinraum.png|thumb|none|Air flow pattern for "Turbulent Cleanroom"]] |[[File:Laminar Flow Reinraum.png|thumb|none|Air flow pattern for "[[Laminar Flow]] Cleanroom"]] |} Cleanrooms maintain particulate-free air through the use of either [[HEPA]] or [[ULPA]] filters employing laminar or turbulent air flow principles. Laminar, or unidirectional, air flow systems direct filtered air downward or in horizontal direction in a constant stream towards filters located on walls near the cleanroom floor or through raised perforated floor panels to be recirculated. Laminar air flow 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 air flow filters and hoods to prevent excess particles entering the air. Turbulent, or non unidirectional, air flow uses both laminar air flow hoods and nonspecific velocity filters to keep air in a cleanroom in constant motion, although not all in the same direction. The rough air seeks to trap particles that may be in the air and drive them towards the floor, where they enter filters and leave the cleanroom environment. US FDA and EU have laid down guidelines and limit for microbial contamination which is very stringent to ensure freedom from microbial contamination in pharmaceutical products.<ref>[http://www.pharmacistspharmajournal.org/2010/02/clean-room-classification-aspects-of.html Limits for Microbial load for clean room as per US FDA and EU Guidelines for pharmaceutical products]</ref><ref>[http://www.thomasnet.com/articles/automation-electronics/Cleanroom-Air-Flow-Principles Cleanroom Air Flow Principles]</ref> == Personnel contamination of cleanrooms== {| class="centered" |- style="vertical-align:top" |} In the healthcare and pharmaceutical sectors, control of microorganisms is important, especially microorganisms likely to be deposited into the air stream from skin shedding. Studying cleanroom microflora is of importance for microbiologists and quality control personnel to assess changes in trends. Shifts in the types of microflora may indicate deviations from the “norm” such as resistant strains or problems with cleaning practices. In assessing cleanroom microorganisms, the typical flora are primarily those associated with human skin (Gram-positive cocci), although microorganisms from other sources such as the environment (Gram-positive rods) and water (Gram-negative rods) are also detected, although in lower number. Common bacterial genera include ''Micrococcus'', ''Staphylococcus'', ''Corynebacterium'', and ''Bacillus'', and fungal genera include ''Aspergillus'' and ''Pencillin''.<ref name="Sandle, T 392–403"/> ==Cleanroom classifications== Cleanrooms are classified according to the number and size of particles permitted per volume of air. Large numbers like "class 100" or "class 1000" refer to [[FED-STD-209E]], and denote the number of particles of size 0.5&nbsp;µm or larger permitted per cubic foot of air. The standard also allows interpolation, so it is possible to describe, for example, "class 2000". A discrete-particle-counting, light-scattering instrument is used to determine the concentration of airborne particles, equal to and larger than the specified sizes, at designated sampling locations. Small numbers refer to ISO 14644-1 standards, which specify the decimal [[logarithm]] of the number of particles 0.1&nbsp;µm or larger permitted per m³ of air. So, for example, an ISO class 5 cleanroom has at most 10⁵ particles/m³. Both FS 209E and ISO 14644-1 assume log-log relationships between particle size and particle concentration. For that reason, zero particle concentration does not exist. The table locations without entries are nonapplicable combinations of particle sizes and cleanliness classes, and should not be read as zero. Because 1&nbsp;m³ is about 35&nbsp;ft³, the two standards are mostly equivalent when measuring 0.5&nbsp;µm particles, although the testing standards differ. Ordinary room air is around class 1,000,000 or ISO 9.<ref>[http://www.ee.byu.edu/cleanroom/particlecount.phtml Cleanroom Classification / Particle Count / FS209E / ISO TC209 /<!-- Bot generated title -->]</ref> ===US FED STD 209E cleanroom standards=== {| class="wikitable" |- ! rowspan="2" | Class | colspan="5" align="center" | maximum particles/ft³ ! rowspan="2" | ISO<br>equivalent |- ! ≥0.1&nbsp;µm ! ≥0.2&nbsp;µm ! ≥0.3&nbsp;µm ! ≥0.5&nbsp;µm ! ≥5&nbsp;µm |- ! 1 | align="right" | 35 | align="right" | 7.5 | align="right" | 3 | align="right" | 1 | align="right" | 0.007 | align="center"| ISO 3 |- ! 10 | align="right" | 350 | align="right" | 75 | align="right" | 30 | align="right" | 10 | align="right" | 0.07 | align="center"| ISO 4 |- ! 100 | align="right" | 3,500 | align="right" | 750 | align="right" | 300 | align="right" | 100 | align="right" | 0.7 | align="center"| ISO 5 |- ! 1,000 | align="right" | 35,000 | align="right" | 7,500 | align="right" | 3000 | align="right" | 1,000 | align="right" | 7 | align="center"| ISO 6 |- ! 10,000 | align="right" | 350,000 | align="right" | 75,000 | align="right" | 30,000 | align="right" | 10,000 | align="right" | 70 | align="center"| ISO 7 |- ! 100,000 | align="right" | {{val|3.5|e=6}} | align="right" | 750,000 | align="right" | 300,000 | align="right" | 100,000 | align="right" | 700 | align="center"| ISO 8 |} US FED STD 209E was officially cancelled by the [[General Services Administration]] on November 29, 2001,<ref>[http://www.iest.org/StandardsRPs/ISOStandards/FEDSTD209E/tabid/10147/Default.aspx Cancellation of FED-STD-209E - Institute of Environmental Sciences and Technology<!-- Bot generated title -->]</ref><ref>http://www.wbdg.org/ccb/FEDMIL/notices.pdf, page 148</ref> but is still widely used.<ref>{{cite web | url=http://www.nufab.northwestern.edu/files/2015/10/NUFAB-Safety-Protocol-Policy-10gsrfd.pdf | title=NUFAB SAFETY & PROTOCOL | accessdate=24 February 2016}}</ref> ===ISO 14644-1 cleanroom standards=== {| class="wikitable" |- ! rowspan="2" | Class | colspan="6" align="center" | maximum particles/m³ ! rowspan="2" | FED STD 209E<br>equivalent |- ! ≥0.1&nbsp;µm ! ≥0.2&nbsp;µm ! ≥0.3&nbsp;µm ! ≥0.5&nbsp;µm ! ≥1&nbsp;µm ! ≥5&nbsp;µm |- ! ISO 1 | align="right" | 10 | align="right" | 2.37 | align="right" | 1.02 | align="right" | 0.35 | align="right" | 0.083 | align="right" | 0.0029 | |- ! ISO 2 | align="right" | 100 | align="right" | 23.7 | align="right" | 10.2 | align="right" | 3.5 | align="right" | 0.83 | align="right" | 0.029 | |- ! ISO 3 | align="right" | 1,000 | align="right" | 237 | align="right" | 102 | align="right" | 35 | align="right" | 8.3 | align="right" | 0.29 | align="center"| Class 1 |- ! ISO 4 | align="right" | 10,000 | align="right" | 2,370 | align="right" | 1,020 | align="right" | 352 | align="right" | 83 | align="right" | 2.9 | align="center"| Class 10 |- ! ISO 5 | align="right" | 100,000 | align="right" | 23,700 | align="right" | 10,200 | align="right" | 3,520 | align="right" | 832 | align="right" | 29 | align="center"| Class 100 |- ! ISO 6 | align="right" | {{val|1.0|e=6}} | align="right" | 237,000 | align="right" | 102,000 | align="right" | 35,200 | align="right" | 8,320 | align="right" | 293 | align="center"| Class 1,000 |- ! ISO 7 | align="right" | {{val|1.0|e=7}} | align="right" | {{val|2.37|e=6}} | align="right" | 1,020,000 | align="right" | 352,000 | align="right" | 83,200 | align="right" | 2,930 | align="center"| Class 10,000 |- ! ISO 8 | align="right" | {{val|1.0|e=8}} | align="right" | {{val|2.37|e=7}} | align="right" | {{val|1.02|e=7}} | align="right" | 3,520,000 | align="right" | 832,000 | align="right" | 29,300 | align="center"| Class 100,000 |- ! ISO 9 | align="right" | {{val|1.0|e=9}} | align="right" | {{val|2.37|e=8}} | align="right" | {{val|1.02|e=8}} | align="right" | 35,200,000 | align="right" | 8,320,000 | align="right" | 293,000 | align="center"| Room air |} ===BS 5295 cleanroom standards=== {| class="wikitable" |- | &nbsp; | colspan="6" align="center" | maximum particles/m³ |- ! Class ! ≥0.5&nbsp;µm ! ≥1&nbsp;µm ! ≥5&nbsp;µm ! ≥10&nbsp;µm ! ≥25&nbsp;µm |- ! Class 1 | align="right" | 3,000 | align="right" | &nbsp; | align="right" | 0 | align="right" | 0 | align="right" | 0 |- ! Class 2 | align="right" | 300,000 | align="right" | &nbsp; | align="right" | 2,000 | align="right" | 30 | align="right" | &nbsp; |- ! Class 3 | align="right" | &nbsp; | align="right" | 1,000,000 | align="right" | 20,000 | align="right" | 4,000 | align="right" | 300 |- ! Class 4 | align="right" | &nbsp; | align="right" | &nbsp; | align="right" | 200,000 | align="right" | 40,000 | align="right" | 4,000 |- |} BS 5295 Class 1 also requires that the greatest particle present in any sample can not exceed 5 μm.<ref>[http://www.mvent.com.ph/references/cleanroom.htm Market Venture Philippines Inc. web site]</ref> ===GMP EU classification=== EU GMP guidelines are more stringent than others, requiring cleanrooms to meet particle counts at operation (during manufacturing process) and at rest (when manufacturing process is not carried out, but room [[Air handler|AHU]] is on). {| class="wikitable" |- ! rowspan="3" | Class | colspan="4" align="center" | '''maximum particles/m³'''<ref>[http://www.cemag.us/articles/2014/03/understanding-cleanroom-classifications Understanding Cleanroom Classifications]</ref> |- | At Rest | At Rest | In Operation | In Operation |- ! 0.5&nbsp;µm ! 5&nbsp;µm ! 0.5&nbsp;µm ! 5&nbsp;µm |- ! Grade A | 3,520 |20 | 35,200 | 20 |- ! Grade B | 35,200 |29 | 352,000 | 2,900 |- ! Grade C | 352,000 |2900 | 3,520,000 | 29,000 |- ! Grade D | 3,520,000 | 29000 | Not defined | Not defined |} ==Environmental benefits of cleanrooms== Cleanrooms offer many environmental benefits that traditional construction often eschews. Modular Cleanrooms provide a re-usable space that saves money on energy, is recyclable and minimizes waste by reducing on-site construction. ==See also== {{Portal|Information technology|Technology}} * [[Air Quality Index]] *[[Data recovery lab]] *[[Secure environment]] *[[ISO 14644]] *[[ISO 14698]] *[[Contamination control]] *[[Pneumatic filter]] *[[Air ionizer]] *[[Semiconductor device fabrication]] ==References== {{Reflist}} ==External links== {{commons category|Cleanrooms}} *[http://www.gsfcc.org Cleanroom Wiki--The Global Society For Contamination Control (GSFCC)] *[http://www.pharmacistspharmajournal.org/2010/02/clean-room-classification-aspects-of.html Clean Room Requirements in Pharma ] *[http://www.iest.org The Secretariat to ISO/TC 209 Cleanrooms and associated controlled environments, the group of experts who negotiate all aspects of the 14644 standard] {{Authority control}} [[Category:Rooms]] [[Category:Semiconductor device fabrication]] [[Category:Filters]] [[Category:Telecommunications engineering]] [[Category:Cleanroom technology]]'