A cleanroom is a highly controlled environment in which various products are manufactured. It is controlled in order to contain a low level of pollutants such as airborne microbes, chemical vapors, aerosol particles and dust. Cleanrooms are typically used in chemistry labs, data recovery companies, and micro chip manufacturing. The concentration of airborne particles in a cleanroom is controlled or regulated to a specific limit. A typical office building normally contains between 500,000 and 1,000,000 particles—which is 0.5 microns or more per cubic foot of air. Cleanrooms often maintain a condition of particulate free air with the use of Ultra Low Particulate Air (ULPA) or High Efficiency Particulate Air (HEPA) filters that use turbulent air flow or laminar principles.
There are several classes or standards of environmental control. They are done according to the number and size of particles in a given volume of air. Here are the classes according to the US FED STD 209E:
|Class||Maximum particles/ft3||ISO Equivalent|
Therefore, a class 100 cleanroom is particularly designed to allow not more than 100 particles per cubic foot of air. Once a cleanroom has been built then it should be maintained according to those original standards in order for it to attain peak performance. Human air measures about 75 to 100 microns in diameter and a particle that is about 200 times smaller than human air can experimentally cause a major disaster in a class 100 or any other higher cleanroom. According to NASA, contamination can easily lead to expensive downtime and higher production costs. Their billion-dollar Hubble Space Telescope was partially damaged and hampered from performing because of a particle sized below 0.5 microns.
In the current age of computers and information, cleanrooms are very essential. Computers and servers don’t perform well when they are exposed to pollutants and other particles. Therefore cleanrooms should be built for optimum performance to be realized. Any personnel hired to work in and maintain a cleanroom should be extensively trained on the contamination control theory. Cleanrooms should be entered through air showers, air locks and gowning rooms. Special clothing should be worn and specially designed to trap contaminants in the room. Working in a normal computer environment should not have all these controls but maintaining cleanroom conditions optimizes the performance of computers.
Contamination of a Cleanroom
This is the process that causes surfaces or materials to be soiled by some substances. The principal categories of surface contaminants include particulates and the film type. They produce a killer defect in a kind of miniature circuit. Particles of 0.5 microns or larger are normally the target of cleanrooms but some industries now want to target even smaller particles in order to boost particles. And everybody that enters the cleanroom should aim at maintaining the same environment. Strict procedures are often followed when cleaning or entering a cleanroom. Compromise halts the production process hence it is not acceptable.
Common sources of Contamination in a Class 100 Cleanroom
The list prepared below shows some of the common contaminants in a cleanroom that can cause serious damage. There are five basic sources of contaminants that massively contribute to lowered production and efficiency in a machining environment. They include:
- Fluids- these are deionized water, outgasses or plasticizers, floor coatings or finishes, moisture, organics, bacteria, particulates that are floating in air and cleaning chemicals.
- Tool generated- these are mops, dusters, brooms, emissions, lubricants, vibrations, wear particles and friction.
- Product generated- these are aluminum particles, quartz flakes, silicon chips and cleanroom debris.
- People- these are hair, spittle, clothing debris (fibers, lint), body oil, skin flakes, perfume and cosmetics.
- Facilities- these are leaks, spills, vapors, room airs, coatings, paintings, ceilings, floors, walls, air conditioning debris and construction materials (saw dust, sheet rock).
General Cleanroom Regulations
For the successful operation of a cleanroom, certain minimum conditions need to be met. All the cleaning personnel need to have these regulations at their fingertips in order to maintain the best condition in the cleanroom. They include:
- Valuable personal items including wallets may be allowed in the cleanroom but they should not be removed from the underside of cleanroom garments.
- All person items including watches, keys, matches, rings, cigarettes and lighters should be carefully stored in a personal locker outside the official gowning room.
- All garments worn in the cleanroom must be pre-approved.
- Cosmetics must not be allowed in a cleanroom. These include eye shadow, mascara, rouge, hair spray, lipstick, fingernail polish, false eye lashes, mousse, perfumes, after shaves and heavy usage of aerosols.
- Only the approved cleanroom papers ought to be allowed in the cleanroom.
- No smoking, gum chewing or eating in the cleanroom.
- People with stomach disorders, respiratory disorders or in any way physically ill ought not to enter the cleanroom.
- No single tool should be allowed on the surface of a table or bench in a cleanroom. All tools should be placed on the cleanroom wiper.
- All materials, equipment and containers that are introduced to a sterile facility need to be subjected to be subjected to maximum stringent sterilization before entrance to the cleanroom.
- Any wiper used in the cleanroom must be pre-approved. A class 100 cleanroom has its own special wipers that are different from those of other classes.
- In order to reduce skin flaking, only approved lanolin based soaps or skin lotions are allowed in the cleanroom.
- Anybody in the cleanroom should avoid solvent contact with their bare skin because solvents can remove oils from the skin and increase skin flaking.
- The use of paper fabric towels is prohibited in the strongest terms. Only hand dryers assorted with HEPA filters are recommended.
- The only writing tool in a cleanroom is an approved ballpoint pen.
- Finger cots or gloves are not allowed to come to contact with any surface or item that has not been thoroughly cleaned.
- Products should only be handled by approved gloves, pliers, finger cots and tweezers.
- All fixtures, containers and tools used in the process of cleaning should be cleaned to the same standard and degree as cleanroom surfaces.
Data recovery from a hard drive is carried out with these standard cleanroom measures. Therefore, you need to contact professional data recovery experts for the best industry standards and results.
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About the Author: Zach Schapel holds a degree in Linguistics from the University of North Carolina at Chapel Hill. Due to his interest in information technology, he has also pursued a Postgraduate Diploma in Information Technology from the same university. He worked in various private schools before joining InterData Recovery as a researcher and writer. He has published numerous articles on information technology, forensic science and software engineering in his capacity as the Chief Writer. With more than 10 years’ experience as a writer now, Zach offers advice and tips on how to handle data recovery issues and concerns. He has won various awards for his editorial work.