Contamination control is the generic term for all activities aiming to control the existence, growth and proliferation of contamination in certain areas. Contamination control may refer to the atmosphere as well as to surfaces, to particulate matter as well as to microbes and to contamination prevention as well as to decontamination.
The aim of all contamination control activities is to permanently ensure a sufficient level of cleanliness in controlled environments. This is accomplished by maintaining, reducing, or eradicating viable and non-viable contamination for either sanitary purposes or in order to maintain an efficient rate of production.
One of the most common environments that incorporates contamination control into its standards protocol is the cleanroom. There are many preventive procedures in place within a cleanroom environment. They include subjecting cleanroom staff to strict clothing regulations, and there is often a gowning room where the staff can change clothes under sterile conditions so as to prevent any particulates from entering from the outside environment. Certain areas in the cleanroom have more stringent measures than others: packaging areas, corridors, gowning rooms and transfer hatches incorporate strict contamination control measures in order to maintain cleanroom standards.
Contamination control is also an important asset for industrial laboratories in the pharmaceutical and life science sectors. Other places of use include automotive paint shops, entrances to industrial kitchens and food service providers, many manufacturing areas, and electronic component assembly areas.
More recently, effective contamination control has been a concern for laboratories and other sensitive environments as a bio-security crisis management measure. Some banks and insurance companies use contamination control products as part of their disaster management protocols. Preventive measures are devised as preparation for combating potential pandemics or the proliferation of biohazards in any potential terrorist attack.
Beside particulate matter such as ions and molecules, the most common types of contamination are:
Many types organisms are potentially detrimental to processes in a critical environment. Seven of the most common contaminants are:
These and many other damaging contaminants can infiltrate critical areas in a number of ways. Particulates can enter by air, or on the feet of any carrier moving between the external environment and inside the critical area, for example.
Contamination poses a significant risk to technical processes, experiments or production activities, as well as to the individuals involved. Unguarded proliferation of contamination can quickly lead to product damage, yield reduction, product recalls and other outcomes highly detrimental to business. Products in a range of industries are recalled due to ineffective contamination control systems.
Based on this evidence it could be argued that many businesses are not adequately protecting themselves from the harmful effects of contamination, and many products in many industries are being recalled due to unsafe manufacturing processes.
Body movement causes contamination, and protective clothing such as hats, cleanroom suits and face masks are accordingly basic items of contamination control. Apart from people, another common way for contamination to enter is on the wheels of trolleys used to transport equipment.
To prevent airborne contamination, high-efficiency particulate air (HEPA) filters, airlocks and cleanroom suits are used. HEPA filtration systems used in the medical sector incorporate high-energy ultraviolet light units to kill the live bacteria and viruses trapped by the filter media. These measures restrict the number of particulates within the atmosphere and inhibit the growth of those that are viable.
Studies by 3M show that over 80% of contamination enters the cleanroom through entrances and exits, mostly at or near floor level. To combat this problem, suitable flooring systems are used that effectively attract, retain and inhibit the growth of viable organisms. Studies show that the most effective type of flooring system is one of polymer composition.
Polymer mats are particularly effective due to their suppleness as they allow for more contact with serrations on shoes and wheels and can accommodate more particles while still remaining effective. An electrostatic potential adds to the effectiveness of this type of contamination control as it enables particles to be retained until the flooring is cleaned. This method of attracting and retaining particles is more effective than mats with an active adhesive coating which needs to be peeled and is often not as supple. As long as the tack level of the mat is greater than the donor's (such as a foot or a wheel), the contamination touching the surface will be removed. Very high tack surfaces pose a contamination threat because they are prone to pulling off overshoe protection. Polymeric flooring is produced to ensure a higher level of tackiness than the surfaces it comes into contact with, without causing discomfort and potentially damaging 'stickiness'.
Copper-alloy surfaces have intrinsic properties which effectively and quickly destroy microbes and they are being installed in healthcare facilities and in a subway transit system as a protective public health measure in addition to regular cleaning. The United States Environmental Protection Agency (EPA) has approved the registration of 355 different antibacterial copper alloys that kill E. coli O157:H7, methicillin-resistant Staphylococcus aureus (MRSA), Staphylococcus, Enterobacter aerogenes, and Pseudomonas aeruginosa. The EPA has determined that when cleaned regularly, these copper alloy surfaces:
As a contamination control measure, EPA has approved a long list of antimicrobial copper products "with public health benefits" made from these copper alloys, such as bedrails, handrails, over-bed tables, sinks, faucets, door knobs, toilet hardware, computer keyboards, health club equipment, shopping cart handles, etc. (For a comprehensive list of products, see: Antimicrobial copper-alloy touch surfaces § Approved products).
Asepsis is the state of being free from disease-causing micro-organisms (such as pathogenic bacteria, viruses, pathogenic fungi, and parasites). The term often refers to those practices used to promote or induce asepsis in an operative field of surgery or medicine to prevent infection.
The goal of asepsis is to eliminate infection, not to achieve sterility. Ideally, a surgical field is sterile, meaning it is free of all biological contaminants (e.g. fungi, bacteria, viruses), not just those that can cause disease, putrefaction, or fermentation. At present, there is no method to safely eliminate all of a patient's contaminants without causing significant tissue damage.Burkholderia cepacia complex
Burkholderia cepacia complex (BCC), or simply Burkholderia cepacia, is a group of catalase-producing, lactose-nonfermenting, Gram-negative bacteria composed of at least 20 different species, including B. cepacia, B. multivorans, B. cenocepacia, B. vietnamiensis, B. stabilis, B. ambifaria, B. dolosa, B. anthina, B. pyrrocinia and B. ubonensis. B. cepacia is an opportunistic human pathogen that most often causes pneumonia in immunocompromised individuals with underlying lung disease (such as cystic fibrosis or chronic granulomatous disease). Patients with sickle-cell haemoglobinopathies are also at risk. The species also attacks young onion and tobacco plants, as well as displaying a remarkable ability to digest oil.Cleaning
Cleaning is the process of removing unwanted substances, such as dirt, infectious agents, and other impurities, from an object or environment. Cleaning occurs in many different contexts, and uses many different methods. Several occupations are devoted to cleaning.Cleanroom
A cleanroom or clean room is a facility ordinarily utilized as a part of specialized industrial production or scientific research, including the manufacture of pharmaceutical items and microprocessors. Cleanrooms are designed to maintain extremely low levels of particulates, such as dust, airborne organisms, or vaporized particles. Cleanrooms typically have an 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 in measurement, equivalent to an ISO 9 cleanroom, while by comparison an ISO 1 cleanroom permits no particles in that size range and just 12 particles for each cubic meter of 0.3 μm and smaller.Controlled Environments Magazine
Controlled Environments Magazine is a business-to-business magazine that provides information on contamination control, detection, and prevention. The magazine is available in both print and online formats and provides information on trends, technology, and applications for professionals working in cleanrooms and similar environments. It is published 11 times a year and covers topics such as pure materials, protective packaging, facility construction, and day-to-day cleaning and control challenges affecting quality and yield. Monthly columns cover precision and critical cleaning, cleanroom apparel, cleanroom chemicals, regulatory issues, and contamination control.
Controlled Environments Magazine also publishes a printed Buyer's Guide annually. The Buyer's Guide is a resource of contamination control vendors, products and services available.Entegris
'Entegris, Inc. is a provider of products and systems that purify, protect, and transport critical materials used in the semiconductor device fabrication process.
Entegris operates out of its headquarters in Billerica, Massachusetts. The company has about 3,500 employees in manufacturing, service center and research facilities in the United States, Malaysia, Singapore, Taiwan, China, Korea, Japan, Israel, Ireland, Germany and France.
The company seeks to help manufacturers increase their yields by improving contamination control in several key processes, including photolithography, wet etching & cleaning, chemical-mechanical planarization, thin-film deposition, bulk chemical processing, wafer and reticle handling and shipping, and testing, assembly and packaging. Approximately 80% of the Company's products are used in the semiconductor industry.Housing (engineering)
In engineering, a housing is an exterior case or enclosure used to protect an interior mechanism, including integrated fittings or brackets to keep internal components in place. The housing prevents the interior mechanism from being fouled by outside debris or to contain the internal components. Housing may be the body of the device, vital to its function.Human decontamination
Human decontamination is the process of removing hazardous materials from the human body, including chemicals, radioactive substances, and infectious material.ISO 11171
ISO 11171 is an international standard for calibrating liquid particle counters. As the functionality of hydraulic fluids suffers when contaminated with particles, particle counters are used for contamination control. The particle counter determines the concentration and the size distribution of the particles. Therefore, the accuracy of the liquid particle counter has to be established through calibration.
According to ISO 11171 for the primary particle-sizing calibration NIST SRM 2806 suspension has to be used. In annex "F" of ISO 11171, preparation of secondary calibration suspension is described.
In general ISO 11171 specifies procedures for two different subjects:
sensor calibration (particle-sizing calibration, coincidence error, resolution and flow rate limit determination etc.)ISO 14698
The ISO 14698 Standards features two International Standards on biocontamination control for cleanrooms. IEST, the Secretariat and Administrator of ISO Technical Committee 209, helped develop this series of ISO 14698 Standards.
ISO 14698-1, Cleanrooms and associated controlled environments—Biocontamination control, Part 1: General principles and methods
ISO 14698-2, Cleanrooms and associated controlled environments—Biocontamination control, Part 2: Evaluation and interpretation of biocontamination dataInstitute of Environmental Sciences and Technology
The Institute of Environmental Sciences and Technology (IEST) is a non-profit, technical society. Information on ISO 14644 and ISO 14698 standards can be found through this organization.
Founded in 1953, the organization is headquartered in Schaumburg, Illinois. Its members are internationally recognized in the fields of environmental tests; contamination control; product reliability; and aerospace.Oil filter
An oil filter is a filter designed to remove contaminants from engine oil, transmission oil, lubricating oil, or hydraulic oil. Oil filters are used in many different types of hydraulic machinery. A chief use of the oil filter is in internal-combustion engines in on- and off-road motor vehicles, light aircraft, and various naval vessels. Other vehicle hydraulic systems, such as those in automatic transmissions and power steering, are often equipped with an oil filter. Gas turbine engines, such as those on jet aircraft, also require the use of oil filters. Aside from these uses, oil production, transport, and recycling facilities also employ filters in the manufacturing process.Radioactive contamination
The sources of radioactive pollution can be classified into two groups: natural and man made.
Radioactive contamination, also called radiological contamination, is the deposition of, or presence of radioactive substances on surfaces or within solids, liquids or gases (including the human body), where their presence is unintended or undesirable (from the International Atomic Energy Agency – IAEA – definition).Such contamination presents a hazard because of the radioactive decay of the contaminants, which emit harmful ionising radiation such as alpha particles or beta particles, gamma rays or neutrons. The degree of hazard is determined by the concentration of the contaminants, the energy of the radiation being emitted, the type of radiation, and the proximity of the contamination to organs of the body. It is important to be clear that the contamination gives rise to the radiation hazard, and the terms "radiation" and "contamination" are not interchangeable.
Contamination may affect a person, a place, an animal, or an object such as clothing. Following an atmospheric nuclear weapon discharge or a nuclear reactor containment breach, the air, soil, people, plants, and animals in the vicinity will become contaminated by nuclear fuel and fission products. A spilled vial of radioactive material like uranyl nitrate may contaminate the floor and any rags used to wipe up the spill. Cases of widespread radioactive contamination include the Bikini Atoll, the Rocky Flats Plant in Colorado, the Fukushima Daiichi nuclear disaster, the Chernobyl disaster, and the area around the Mayak facility in Russia.Radioactivity Fixatives
Radioactivity or radionuclide fixatives are specialized polymer coatings used to “fix” radioactive isotopes or radioactive material to surfaces. These fixatives, also known as permanent coatings in the radioactive contamination control field, have been used for many decades in facilities processing radioactive material to control radioactive contamination. There has been increased interest in these fixatives or coatings recently due to the growing concern of contamination from a radioactivity dispersal device (RDD also known as a dirty bomb) and because radioactivity fixatives in use today lose the ability to contain the radioactivity to the surface during a fire.
Radioactivity fixatives reduce or eliminate the movement of radionuclides from surfaces thereby lowering the health risk of inhalation or other exposure to radioactive isotopes. There are many articles on the use of radioactive fixatives with a review article from 1983 often used as a reference. A more recent review article looks at the use of these radioactive fixatives for use after the detonation of a RDD. Current research is investigating new coatings that are effective at containing radioactive material to the surface during and after fires.Writing in space
Several instruments have been used to write in outer space, including different types of pencils and pens. Some of them have been unmodified versions of conventional writing instruments; others have been invented specifically to counter the problems with writing in space conditions.
A common urban legend states that, faced with the fact that ball-point pens would not write in zero-gravity, NASA spent a large amount of money to develop a pen that would write in the conditions experienced during spaceflight (the result purportedly being the Fisher Space Pen), while the Soviet Union took the simpler and cheaper route of just using pencils. The Fisher Space Pen was developed independently by a private organization in the 1960s.Today, when practically all writing in space intended for permanent record (e.g., logs, details and results of scientific experiments) is electronic, the discussion of writing instruments in space is somewhat academic: hard copy is produced infrequently. The laptops used (as of 2012, IBM/Lenovo ThinkPads) need customization for space use, such as radiation-, heat- and fire-resistance.