Clean room technology can be divided into three parts: design, construction, operation. Cleanroom construction than other building construction requirements are higher, and a variety of clean room production of different varieties of products, the requirements of the air cleanliness level is different, so a variety of clean room engineering and construction content there are some differences. But its basic construction content such as clean room building decoration, purification and air conditioning systems, electrical lighting systems, fire safety alarm systems, etc. is basically the same, the difference is due to the different needs of the product production process, the increase in the corresponding measures, supply systems and so on. The following talk about the construction of clean air conditioning system to pay attention to several issues.
1 must follow the corresponding norms and requirements of clean air conditioning
"Clean Plant Design Code", "Cleanroom Construction and Acceptance Code", "Ventilation and Air Conditioning Construction and Acceptance Code", "Hospital Clean Surgery Department Building Technical Specification" and so on is the main specification of clean, the specification of the requirements of the clean room materials, construction and decorative requirements, as well as the clean room decorative Surface quality requirements. Must fully understand the design intent, strict implementation of the national project quality management documents, rigorous organization and construction to ensure quality.
2 Strictly good materials
At present, most of the domestic cleanroom metal wall plate assembly structure, its biggest advantage is:
(1) tight seams, reduce the indoor dust environment, suitable for high cleanliness room;
(2) according to the user's needs to design the shape of the wall and the room, whether it is octagonal or rounded are not subject to the limitations of the plate size. The size of the panel is not limited.
Commonly, there are stainless steel structure, carbon steel structure and electrolytic plate structure, aluminum and aluminum composite plate structure, in recent years, with the rapid development of the materials industry, the application of color steel plate is also more and more.
Clean air-conditioning system ducts are generally galvanized steel processing. Galvanized steel should be selected from high-quality plate, galvanized layer standard suitable for > 314g / m2, and should be uniformly plated, no shelling, no oxidation. Hanger, reinforcing frame, connecting bolts, duct flange, rivets should be galvanized parts, flange gasket should be used elastic, non-dust-producing, have a certain degree of strength of the soft rubber or latex sponge, air ducts can be used for external insulation capacity of more than 32K flame-retardant PE board to special adhesive stickers, shall not be used in the use of glass wool and other fiber products.
Cleanroom floor is also an important part of indoor cleanliness, the material requirements are non-slip, anti-static, wear-resistant, corrosion-resistant, easy to clean. Common cleanroom floor: cast-in copper embedded terrazzo floor, plastic flooring, and rubber flooring (generally paved with self-leveling materials before leveling the ground).
In the material procurement process, must be planned, according to the varieties of the same product with quality assurance of the manufacturer's products. Physical inspection should also pay attention to the material specifications, material finish, the plate should also check the flatness, squareness of the corners, galvanized layer of bonding. Procurement after the transportation and storage process should also pay attention to maintain good packaging, moisture, impact and pollution.
3 Reasonable arrangement of the construction sequence is to ensure the cleanliness of the foundation
Reasonable construction program principles are:
"eight successive",
"six at the same time".
That is: first clean up after the installation of health; first upper lifting after the installation of the middle; first partition after the ceiling; first large equipment into the partition after the closure; first purification installation after the process of installation; the internal decoration of the first after the next, first inside after the outside; clean room is completed after the ground treatment; first adjusted after the test. "Six simultaneous" is: equipment organization and engineering at the same time; accessories production and material organization at the same time; air-conditioning piping installation and process piping installation at the same time; clean system engineering and delivery of air-conditioning equipment at the same time; clean system engineering at the same time the professional trial run, at the same time to adjust the test; civil engineering and clean installation of the final part of the project At the same time. Specific construction, must ensure that the previous process of finished products, semi-finished products are not damaged, construction between different specialties cross operation must be sincere cooperation, a high degree of unity of command.
Construction of assembly clean system in a variety of trunk pipe basic installation is completed, the indoor ground, columns, walls, space for a thorough cleaning to achieve clean and dust-free before starting. The process is divided into ceiling installation and wall panel installation.
Top installation: site preparation - measurement and demarcation - ceiling hole - support frame keel installation, adjustment - ceiling installation, do mouth guard installation - air outlet, lighting base plate installation Lighting installation - tearing film, cleaning, gluing - air blowing, cleaning - high-efficiency filter installation.
Wallboard installation: site preparation - measurement and placement - wallboard keel installation - various professional pre-buried parts - doors, windows, air shower room installation - tearing film, cleaning, gluing - air blowing cleaning -Return air louvers, residual pressure valve installation.
4 clean air duct production, handling, installation is to ensure
Cleanliness of the key
Many constructors in the construction of the special requirements of the installation of clean systems will be noted, that is: the installation site is clean; the system is installed clean (plastic film sealing); the site, the installation of personnel dressed in clean clothes; the selection of non-dust-producing materials; the joints should be tight, to prevent leakage and so on. However, there are still a few points to note:
Seams: Do not allow transverse seams, longitudinal seams should also be as little as possible, when the bottom edge is less than or equal to 800mm, the bottom edge is not allowed to have longitudinal seams;
Nibbles: should try to use joint corner or corner nibbles, 6 or more clean ducts shall not be used to press the button type of nibble;
Sealing: All nibble seams, flanges flap and rivets must be coated with sealant. rivets must be coated with sealant to prevent air leakage; various gaskets are strictly prohibited surface coating;
Reinforcement: not allowed to be located in the pipe;
Flanges: four corners of the screw holes should be set up, hole spacing of less than 100mm, screws, nuts, gaskets and rivets should be zinc-plated;
Measuring holes: pipe diameter of more than 500mm should be set up to clean and a variety of measuring holes; storage: after the completion of the production of the Neutral cleaning fluid cleaning, drying and sealing with plastic film to be installed;
Unsealing: only allowed in the installation to open the pipe port sealing film, the installation of intermediate pause should be sealed again when the port;
Cleaning: Duct parts and components should be installed to remove the surface of the grease and dust, and the use of non-fibrous material is not easy to fall off the internal surface of the system wiped several times;
Leakage check: after the system is installed, the insulation before the leakage check. (1 ~ 5 level system according to the high-pressure system duct provisions, 6 ~ 9 level system according to the implementation of the medium-pressure system duct), you can use more than 100W low-pressure lighting leakage detection, low-pressure system leakage point per 10 meters of joints is not greater than 2, per 100 meters on average is not greater than 16 as qualified; medium-pressure system leakage point per 10 meters of joints is not greater than 1, per 100 meters on average is not greater than 8 as qualified.
5 requirements for the installation of high-efficiency filters
Installation of high-efficiency filters is also the key to the construction of the clean room. It is necessary to clean the clean room again after 12 hours of trial operation of the system before removing the packaging of high-efficiency filters, carrying out on-site leakage check after appearance check (focusing on checking the sealing quality of the filter frame), and then doing resistance blending.
6 clean room pressure control is an important condition to ensure cleanliness
China's "Clean Plant Design Code" in the clean room pressure control has the following provisions: clean room and the surrounding space must maintain a certain pressure difference, and in accordance with the requirements of the production process to determine the maintenance of positive or negative pressure difference. The pressure difference between different levels of clean room and clean area and non-clean area is not less than 5Pa, and the pressure difference between clean area and outdoor should be not less than 10Pa. When considering the control of pressure difference in the clean room, the determination of the pressure difference air volume in the clean room at home and abroad, most of them use the number of air changes in the room to estimate the number of times, which requires the designers and constructors to pay enough attention to the concept of the number of times of air changes. Clean air conditioning system of the number of air changes at least 10 times / h or more, or even up to hundreds of times. The actual project is often because of the building's columns, beams and other protruding structures lead to send, return air system resistance is too large, resulting in the number of air changes can not meet the design requirements. If the use of non-unidirectional flow of double-walled back to the top of the air supply airflow organization, this situation is more obvious.
7 project acceptance, maintenance work should also be done
Clean room construction is completed, the operation and management of the clean room is also very important to regularly check the indoor and equipment, equipment, mainly to monitor the indoor project in addition to the conventional indoor ceiling air supply ceiling (or high-efficiency air supply outlet) and the wall back to the wall outlet visually cleanliness and other items that must be monitored, more importantly, it should also include Dust particles, bacteria colonies, air volume, indoor positive (negative) pressure. Daily management must ensure that the cleanroom operates correctly so that the products manufactured are not contaminated. This requires that everything from the admission of personnel and materials, to the selection of clothing, clean room regulations, and clean room cleaning must be implemented correctly. Maintenance personnel should also be trained if necessary.