Background information on cleanroom features and cleanliness levels in various industries
2026-03-01
Electronics industry:
The development of computer, microelectronic and information technologies has contributed to the rapid growth of the electronics industry, which in turn has led to the development of clean room technologies and placed higher demands on their design. Designing cleanrooms for the electronics industry is a complex technology, and only with a full understanding of the design features and development of rational solutions can the defect rate of products in the electronics industry be reduced and production efficiency increased.
Features of cleanrooms in the electronics industry:
A high level of cleanliness is required; air flow, temperature, humidity, pressure drop and equipment exhaust are adjusted according to needs; illumination and air flow speed in the cross-section of the clean room are controlled in accordance with the design or standards; In addition, the electrostatic discharge requirements in such cleanrooms are extremely stringent. Particularly high demands are placed on humidity. This is because static electricity is very easy to generate in an excessively dry environment, causing damage to CMOS integrated circuits. As a rule, the temperature in the premises of electronic factories should be maintained at about 22 ° C, and the relative humidity - within 50-60% (for special clean shops, appropriate temperature and humidity standards apply). Under such conditions, static electricity can be effectively eliminated and also ensure people's comfort. Chip manufacturing facilities, integrated circuit cleanrooms, and hard drive manufacturing facilities are an important part of cleanrooms in the electronics industry. Since the manufacturing and manufacturing process of electronic products places extremely strict requirements on indoor air condition and quality, the control of particles and airborne dust is emphasized, and strict standards are set regarding ambient temperature and humidity, fresh air quantity, noise, etc.
1. Noise level in Class 10,000 cleanrooms in electronics manufacturing plants (empty): shall not exceed 65 dB(A).
2. The fill factor in clean rooms with vertical flow at electronics production plants should not be less than 60%, and in clean rooms with horizontal unidirectional flow - not less than 40%; otherwise it is a local unidirectional flow.
3. The static pressure difference between the clean room of an electronics manufacturing plant and the external environment should not be less than 10 Pa, and the static pressure difference between areas with different degrees of air cleanliness and unclean areas should not be less than 5 Pa.
4. The fresh air flow rate in a Class 10,000 cleanroom in the electronics industry shall be the maximum of the following two:
(1) The amount of fresh air flow required to compensate for indoor exhaust air flow and maintain positive indoor pressure.
(2) A volume of fresh air supplying at least 40 m³ per person per hour to the clean room.
(3) Heaters for air conditioning and air purification systems in clean rooms of electronics manufacturing plants must be equipped with overheat protection and over-temperature shutdown; when spot moistening, protection against lack of water should be provided; In cold regions, supply air systems must be equipped with freeze protection. The supply air flow rate in the clean room should take the maximum value from the following three: supply air flow rate that provides the required air cleanliness class in the clean room of the electronic plant; supply air flow calculated based on heat and humidity load; volume of fresh air supplied to the clean room of an electronic factory.
Bioproduction:
Features of biopharmaceutical plants:
1. Biopharmaceutical plants are characterized not only by the high cost of equipment, the complexity of production processes and high requirements for the level of cleanliness and sterility, but also by strict requirements for the qualifications of production personnel.
2. During the production process, potential biological hazards arise, mainly related to the risk of infection, toxicity, allergenicity and other biological reactions of dead bacteria or cells, their components or metabolic products in relation to humans and other organisms, as well as the toxicity, allergenicity and other biological reactions of the product, and the impact on the environment.
Clean area:
The room (zone) in which it is necessary to control environmental pollution by dust particles and microorganisms; its architectural design, equipment and use serve the function of preventing the entry, generation and retention of pollutants in the area.
Airlock chambers:
An isolated space with two or more doors, located between two or more rooms (for example, between rooms with different levels of cleanliness). Airlocks are installed to control air flow as personnel or materials enter and exit. Airlock chambers are divided into airlock chambers for personnel and airlock chambers for materials.
Key characteristics of cleanrooms in biopharmaceuticals: The objects of environmental control are particulate matter and microorganisms.
The cleanliness of drug manufacturing facilities is divided into four levels: local levels of 100, 1000, 10,000 and 30,000 with a general background level of 100 or 10,000.
Temperature in the clean room: if there are no special requirements - 18-26 °C, relative humidity - 45-65%.
Contamination control in biologics production cleanrooms: source control, propagation control, cross-contamination control.
The key technologies in drug manufacturing cleanrooms are mainly dust and microorganism control; As contaminants, microorganisms are a priority in the control of cleanroom environments.
Contaminants that accumulate in equipment and pipelines in clean areas of pharmaceutical production can directly contaminate drugs, but do not in any way affect the results of cleanliness control. Purity classes are not applicable to characterize the physical, chemical, radioactive and biological properties of suspended particles. Ignorance of technological processes for the production of medicinal products, lack of understanding of the causes of pollution and places of accumulation of pollutants, as well as lack of knowledge about methods for removing pollutants and criteria for their assessment.
During the technical modernization of pharmaceutical production in accordance with GMP, the following situations are widespread:
It is because of these misconceptions that purification technologies are not used effectively in the pollution control process, with the result that some pharmaceutical companies, despite investing huge amounts of money in modernization, do not achieve noticeable improvements in the quality of medicines.
Product quality is affected by factors such as the design and construction of cleanrooms, the fabrication and installation of equipment and infrastructure, the quality of raw materials, auxiliary materials and packaging materials, and ineffective implementation of personnel and material cleanliness procedures.
The reasons affecting the quality of products from the construction side are problems in the process control stage, as well as hidden risks remaining during the installation and construction process, which manifest themselves as follows:
① Uncleanliness of the internal walls of the air ducts of the purification and air conditioning system, leaky connections, excessive air leakage;
② Leakage of colored steel plate enclosing structures, improper sealing measures for clean rooms and technical interfloor space (ceiling), leakage of sealed doors;
③ Decorative profiles and process pipelines create “dead zones” in the clean room in which dust accumulates;
④ In some places, the construction does not meet the design requirements, which makes it impossible to comply with the relevant regulatory requirements;
⑤ The sealant used does not meet the quality requirements and is easy to peel off and deteriorate;
⑥ The supply and exhaust air ducts, made of colored steel plate, are connected to each other, causing dust to flow from the exhaust duct to the supply air duct;
⑦ when welding stainless steel sanitary pipelines for process purified water, water for injection, etc., internal seams are not formed;
⑧ Air duct check valves are faulty, reverse air flow leads to pollution;
⑨ poor-quality installation of the drainage system; dust easily accumulates on pipe supports and fittings;
⑩ Incorrect pressure differential settings in the clean room, inconsistent with the requirements of the production process.
Printing and packaging industry:
As society develops, the quality of the printing and packaging industry's products also improves. Large-sized printing equipment has begun to be installed in clean rooms, which can significantly improve the quality of printed products and significantly increase their level of compliance with standards. This is the best example of the integration of the clean room industry and the printing industry. In printing, the most important role is played by the temperature and humidity in the room, as well as the amount of small particles in the air, which directly affects the quality of the product and the proportion of suitable products. In the packaging industry, the main requirements relate to indoor temperature and humidity, the amount of fine particles in the air and water quality, especially in the field of food and pharmaceutical packaging. Of course, standardized operating procedures for production personnel also play an equally important role.
Dust-free spraying is carried out in a separate closed production workshop, built from steel sandwich panels, which allows you to effectively filter product contamination from unfavorable air conditions, reduce the amount of dust in the spraying area and the percentage of product defects. The application of dust-free coating technology further improves the appearance quality of products such as TV/computer cases, mobile phones, DVD/VCD players, game consoles, VCRs, PDAs, cameras, audio equipment, hair dryers, MD players, cosmetic bags, toys, etc. Process: loading area → manual dust cleaning → electrostatic dust cleaning → manual/automatic coating → drying zone → UV curing zone → cooling zone → screen printing zone → quality control zone → receiving zone.
To demonstrate satisfactory operation of a food packaging cleanroom, it must be demonstrated that it meets the following requirements:
1. The supply air flow rate in a food packaging clean room must be sufficient to dilute or eliminate contaminants generated in the room.
2. The air in a food packaging cleanroom should be circulated from the clean area to areas of lower cleanliness, with the movement of contaminated air being kept to a minimum and the direction of air flow at the entrance and inside the room should be correct.
3. Introducing air into a food packaging cleanroom does not significantly increase indoor contamination.
4. The dynamics of air movement in a clean room for food packaging should ensure that there are no areas with high concentrations of contaminants.
If the cleanroom meets the above requirements, particle or microbial concentration measurements (if necessary) can be performed to confirm compliance with established cleanliness standards.
Testing cleanrooms for food packaging:
1. Supply and exhaust air flow: If we are talking about a clean room with turbulent flow, it is necessary to measure the supply and exhaust air flow. If it is a clean room with unidirectional flow, it is necessary to measure the air flow velocity.
2. Control of air flows between zones: to confirm the correct direction of air flow between zones, that is, from an area with a higher level of cleanliness to an area with a lower level of cleanliness, it is necessary to check:
(1) correct pressure differential between zones;
(2) the correct direction of air flow in openings near doors, walls, floors, etc., that is, from an area with a higher level of cleanliness to an area with a lower level of cleanliness.
3. Checking the tightness of filters: High efficiency filters and their frames should be checked to ensure that suspended contaminants do not enter the room through:
(1) damaged filters;
(2) clearances between the filter and its frame;
(3) other parts of the filter device.
4. Insulation Leak Test: This test is carried out to ensure that suspended contaminants do not enter the clean room through building materials.
5. Room Air Flow Control: The type of air flow control test depends on whether the clean room air flow is turbulent or unidirectional. If the air flow in the cleanroom is turbulent, you need to ensure that there are no areas in the room with insufficient air circulation. If it is a unidirectional flow cleanroom, you need to ensure that the airflow speed and direction throughout the room meets design requirements.
6. Concentration of suspended particles and microorganisms: If the above tests satisfy the requirements, finally measurements of the concentration of particles and microorganisms (if necessary) are carried out to confirm their compliance with the specifications of the clean room design.
7. Other tests: In addition to the above pollution control tests, it is sometimes necessary to carry out one or more of the following tests: temperature; relative humidity; power of the heating and cooling system of the room; noise level; illumination; vibration level.
Clean rooms for packaging of medicines:
1. Requirements for environmental control:
(1) The level of air purification required for production must be ensured. The number of particulates and living microorganisms in the air of packaging cleanrooms should be regularly checked and recorded; The static pressure difference between cleanrooms for packaging of different classes must be maintained within specified values.
(2) The temperature and relative humidity in packaging cleanrooms must be consistent with the requirements of the manufacturing process.
(3) In production areas of drugs of the penicillin group, highly allergenic and antitumor drugs, autonomous air conditioning systems must be installed, and the exhaust air must be purified.
(4) In areas where dust is generated, effective dust collection devices must be installed to prevent dust cross-contamination.
(5) In auxiliary production areas such as warehouses, ventilation systems, as well as temperature and humidity must meet the requirements for the production and packaging of medicinal products.
2. Cleanliness zones and frequency of air exchange: In cleanrooms, it is necessary to strictly control the cleanliness of the air, as well as parameters such as temperature, humidity, amount of fresh air and pressure drop.
(1) Cleanliness levels and air exchange rates in drug production and packaging areas. In air purification projects in drug production and packaging workshops, air cleanliness is divided into 4 levels: 100, 10,000, 100,000 and 300,000. To determine the air exchange rate in a clean room, it is necessary to compare all air flow rates and take the maximum value. In practice, the air exchange rate for class 100 is 300–400 times/hour, for class 10,000—25–35 times/hour, for class 100,000—15–20 times/hour.
(2) Cleanliness zones in drug packaging facility cleaning projects. The specific division of the production and packaging environment for medicines into cleanliness zones is carried out in accordance with national cleanliness standards.
(3) Determination of other environmental parameters in packaging plant cleaning projects.
(4) Temperature and humidity in a packaging workshop cleaning project. The temperature and relative humidity in the clean room must be appropriate for the drug manufacturing process.
Temperature: for classes 100 and 10,000 - 20-23 °C (summer), for classes 100,000 and 300,000 - 24-26 °C, for the general area - 26-27 °C. Classes 100 and 10,000 are for sterile environments. Relative humidity: for medicines that easily absorb moisture, 45–50% (in summer); for tablets and other solid dosage forms - 50–55%; for aqueous solutions for injections and oral solutions - 55–65%.
(5) Clean room pressure. To keep the room clean, positive pressure must be maintained. In cleanrooms where dust is generated, harmful substances are released, or highly allergenic drugs such as penicillin are produced, it is necessary to prevent the entry of external contaminants or maintain relative negative pressure between zones. In rooms with different cleanliness classes, it is necessary to ensure the flow of air from rooms with a higher cleanliness class and the outflow of air from the interior. Inside the room, it is necessary to maintain positive pressure with a difference in relation to adjacent rooms of more than 5 Pa, and the pressure difference between the clean room and the external atmosphere must be more than 10 Pa.
Food industry:
Food is the basis of life and diseases come through the mouth, so safety and hygiene in the food industry occupy an important place in our daily lives. Ensuring food safety and hygiene mainly depends on control in three aspects: first, on compliance of production personnel with work standards; secondly, from preventing contamination from the outside (it is necessary to create a workspace with a relatively high degree of cleanliness); thirdly, from eliminating problematic raw materials at the procurement stage.
The area of the food production workshop must correspond to the volume of production, the layout must be rational, and the drainage must be uninterrupted; the workshop floor must be made of non-slip, durable, waterproof and corrosion-resistant material, be level, free from accumulations of water and kept clean; at the exits from the workshop and in places connecting it with the external environment (drainage, ventilation), devices must be installed to protect against rodents, flies and insects. The interior walls, ceiling, windows and doors of the workshop should be made of non-toxic, light-colored, waterproof, mildew-resistant, non-flaking and easy to clean materials. The corners of walls, floors and ceilings must be rounded (radius of curvature of at least 3 cm). Work tables, conveyor belts, transport carts and tools in the workshop must be made of non-toxic, corrosion-resistant, stainless, easy to clean and disinfect durable materials. Sufficient hand washing, disinfection and hand drying equipment or supplies should be provided at suitable locations; Cranes must have non-manual control. Depending on production needs, means for disinfecting shoes, boots and wheels should be installed at the entrance to the workshop. A locker room connected to the workshop must be equipped. Depending on the production needs, toilets and showers connected to the workshop should also be equipped.
Optoelectronics:
Optoelectronic and optical manufacturing cleanrooms are commonly used in industries such as electronics and instrumentation, computers, semiconductors, automotive, aerospace, photolithography, and chip manufacturing. In addition to air cleanliness, it is also necessary to ensure compliance with regulations to eliminate static electricity. Below, using the example of one of the most typical modern industries - the production of LEDs - a description of cleanrooms in the optoelectronic and optical industry will be presented.
Case study of installation and construction of cleanrooms for the LED industry: This project deals with the installation of cleanrooms for final processes, the cleaning level of which is usually class 1000, 10000 or 100000. The installation of cleanrooms for the production of backlit screens mainly concerns cleanrooms for stamping and assembly of such products, the cleaning level of which is usually class 10000 or 100 000.
Requirements for indoor air parameters when installing LED equipment in a clean room:
1. Temperature and Humidity Requirements: Temperature is generally 24±2°C, relative humidity is 55±5%.
2. Fresh air flow: Since there are quite a lot of people in these purified cleanrooms, the maximum value should be selected from the following: 10-30% of the total fresh air flow in the cleanroom without unidirectional flow; the volume of fresh air required to compensate for the exhaust and maintain positive pressure in the room; ensuring fresh air flow per person per hour ≥ 40 m³/h.
3. High supply air flow. To ensure cleanliness and heat-humidity balance in a clean room, a large flow of supply air is required. For a room of 300 m² with a ceiling height of 2.5 m, if it is a class 10,000 clean room, the supply air flow rate should be 300 × 2.5 × 30 = 22,500 m³/h (air exchange rate ≥ 25 times/h); if it is a clean, dust-free workshop of class 100,000, the supply air flow rate should be 300 * 2.5 * 20 = 15,000 m³/h (air exchange frequency ≥15 times/h).
Healthcare:
Air purification technology is also known as clean room technology. In addition to meeting standard requirements for temperature and humidity in air-conditioned rooms, thanks to various engineering systems and strict control, the content of microparticles, air flows, pressure and other parameters in the room are maintained within certain limits; Such rooms are called clean rooms. Cleanrooms are built and used in hospitals. With the development of healthcare and high technology, cleaning technologies are increasingly used in the medical environment, and the requirements for them are becoming increasingly higher. Cleanrooms used in medicine are mainly divided into three categories: clean operating rooms, clean rooms and clean laboratories.
Clean operating rooms:
Clean operating rooms are designed to control the microbiological situation in the room; operational and classification parameters as well as air cleanliness are necessary conditions to ensure this. Clean operating rooms are divided into the following classes depending on the degree of cleanliness:
1. Extra clean operating room: the degree of cleanliness in the operating area is 100 class, in the surrounding areas - 1000 class. Suitable for sterile surgeries such as burn treatment, joint replacement, organ transplantation, neurosurgery, ophthalmology, plastic surgery and cardiac surgery.
2. Clean operating room: the degree of cleanliness in the operating area is 1000 class, in the surrounding areas - 10,000 class. Suitable for sterile procedures in the fields of thoracic surgery, plastic surgery, urology, hepatobiliary surgery, orthopedics, as well as egg retrieval procedures.
3. General purpose operating rooms: the cleanliness level of the operating area is 10,000, the surrounding areas are 100,000. Suitable for operations in the field of general surgery, dermatology and abdominal surgery.
4. Semi-clean operating rooms: air purity level - 100,000. Suitable for operations in the field of obstetrics and proctology.
In addition to the fact that the premises of the clean operating room department must correspond to the appropriate level of cleanliness and bacteria concentration, their technical parameters must also comply with the relevant standards (see the table of the main technical parameters of the premises of the clean operating room department at various levels). According to general requirements, the layout of a clean operating room department should be divided into two parts: a clean area and an unclean area.
Operating rooms and functional rooms directly serving operating rooms should be located in a clean area. When moving people and objects between areas of varying degrees of cleanliness, airlocks, buffer rooms or transfer windows must be provided in the operating room.
Typically, operating rooms are located in the central part. The internal layout and shape of passages must comply with the principles of a functional layout and a clear separation of clean and contaminated areas.
Several types of intensive care rooms in a hospital:
Intensive care wards are divided into isolation wards and intensive care wards. Isolation rooms are divided into four levels based on biohazard: P1, P2, P3 and P4. P1 wards are practically no different from ordinary wards, and the entry of unauthorized persons into them is not limited; P2 rooms have stricter requirements than P1 rooms and are generally prohibited from entry by unauthorized persons; P3 wards are isolated from the external environment using double doors or buffer rooms, negative pressure is maintained inside the wards; P4 wards have an isolated area separated from the outside environment, a constant negative pressure of 30 Pa is maintained inside the wards, and medical staff wear protective clothing to prevent infection. Intensive care units include Intensive Care Units (ICU), Cardiac Intensive Care Unit (CCU), Neonatal Intensive Care Unit (NICU) and Leukemia Units, etc. In Leukemia wards, the air temperature is 24-22 °C, the air flow speed is 0.15-0.3 m/s, the relative humidity is not more than 60%, the degree of cleanliness is 100 class; in this case, the cleanest supply air should flow primarily to the patient’s head, and the breathing zone (mouth and nose) should be located on the air supply side, for which it is better to use a horizontal flow. Studies of the concentration of microorganisms in burn rooms show that the use of vertical laminar flow has clear advantages in open treatment: flow speed 0.2 m/s, temperature 28-34 ° C, cleanliness level 1000. Rooms for patients with respiratory diseases are rare in the country; Quite strict requirements are imposed on the temperature and humidity in such chambers: the temperature must be maintained in the range of 23–30 °C, relative humidity - 40–60%; in each room these parameters can be adjusted to suit the individual needs of patients; the degree of purity should be maintained at a level of 10 to 10,000; The noise level must be below 45 dB(A); personnel entering the ward must undergo disinfection procedures, including changing clothes and airing; Positive pressure is maintained in the room.
Clean laboratories:
Clean laboratories are divided into conventional clean laboratories and biosafety laboratories. Experiments carried out in regular clean laboratories are not infectious, but it is required that the environment does not adversely affect the experiment itself; Therefore, such laboratories do not provide protective equipment, and the degree of purity must meet the requirements of the experiment.
Biological safety laboratories are equipped with first-level protection and allow biological experiments to be carried out with second-level protection. Biosafe laboratories are essential for conducting scientific experiments in areas such as microbiology, biomedicine, functional research and gene recombination. The main principle of biological safety laboratories is safety. Depending on the degree of biological hazard, they are divided into four levels: P1, P2, P3 and P4.
P1 laboratories are suitable for work with well-studied pathogens that rarely cause disease in healthy adults and pose little risk to personnel or the environment. During experiments, doors should be kept closed and work carried out in accordance with procedures for routine microbiological experiments;
P2 level laboratories are designed to work with pathogens that pose a medium potential risk to humans and the environment. Access to the experimental area is limited; experiments in which the formation of aerosols is possible should be carried out in biological cabinets of level II, and the laboratory must have an autoclave;
P3 laboratories are used in clinical, diagnostic, teaching, or manufacturing settings to work with endogenous and exogenous pathogens that, when inhaled, can cause severe, potentially fatal illness. The laboratory is equipped with double doors or an airlock and an experimental area isolated from the external environment; entry to unauthorized persons is prohibited; constant negative pressure is maintained in the laboratory; experiments are carried out in biological cabinets of level II, and the air from the room, after filtration using highly efficient filters, is removed to the outside; P4 level laboratories are subject to more stringent requirements than P3 level laboratories. Some dangerous exogenous pathogens pose a high individual risk of becoming infected in the laboratory and developing life-threatening disease through aerosol transmission; relevant work should be carried out in P4 level laboratories. A design is used with an isolated zone inside a separate building and an external partition; negative pressure is maintained in the room; Biological cabinets of level III are used to conduct experiments; air insulation devices and showers are installed; operating personnel must wear protective clothing; Persons who are not employees of this institution are prohibited from entering. The basis of biosafety laboratory design is dynamic containment; Particular attention is paid to air extraction measures, on-site disinfection, separation of clean and contaminated areas, preventing unintentional spread and ensuring adequate levels of cleanliness.
