With the application of clean room, the use of clean room air conditioning system has become more and more widespread, and the level of cleanliness is also improving. Many clean room air conditioning system have been successful through careful design and careful construction, but some clean room air conditioning systems have been downgraded or even scrapped for general air conditioning after design and construction because they cannot meet the cleanliness requirements. The technical requirements and construction quality requirements of clean room air conditioning systems are high, and the investment is large. Once it fails, it will cause waste in terms of financial, material and human resources. Therefore, in order to do a good job in clean room air conditioning systems, in addition to perfect design drawings, high-quality and high-level scientific construction is also required.
1. The material for making air ducts is the basic condition for ensuring the cleanliness of clean room air conditioning system.
Material selection
The air ducts of clean room air conditioning systems are generally processed with galvanized steel sheet. Galvanized steel sheets should be high-quality sheets, and the zinc coating standard should be >314g/㎡, and the coating should be uniform, without peeling or oxidation. Hangers, reinforcement frames, connecting bolts, washers, duct flanges, and rivets should all be galvanized. Flange gaskets should be made of soft rubber or latex sponge that is elastic, dust-free, and has a certain strength. The external insulation of the duct can be made of flame-retardant PE boards with a bulk density of more than 32K, which should be glued with special glue. Fiber products such as glass wool should not be used.
During the physical inspection, attention should also be paid to material specifications and material finish. The plates should also be checked for flatness, corner squareness, and adhesion of the galvanized layer. After the materials are purchased, attention should also be paid to maintaining intact packaging during transportation to prevent moisture, impact, and pollution.
Material storage
Materials for clean room air conditioning system should be stored in a dedicated warehouse or in a centralized manner. The storage place should be clean, free of pollution sources, and avoid moisture. In particular, components such as air valves, air vents, and mufflers should be tightly packaged and stored. The materials for clean room air conditioning system should shorten the storage time in the warehouse and should be purchased as needed. The plates used to make air ducts should be transported to the site as a whole to avoid pollution caused by the transportation of loose parts.
2. Only by making good ducts can the cleanliness of the system be guaranteed.
Preparation before duct making
The ducts of clean room systems should be processed and made in a relatively sealed room. The walls of the room should be smooth and dust-free. Thickened plastic floors can be laid on the floor, and the joints between the floor and the wall should be sealed with tape to avoid dust. Before duct processing, the room must be clean, dust-free and pollution-free. It can be cleaned repeatedly with a vacuum cleaner after sweeping and scrubbing. Tools for making ducts must be scrubbed with alcohol or non-corrosive detergent before entering the production room. It is impossible and unnecessary for the equipment used for making to enter the production room, but it must be kept clean and dust-free. The workers participating in production should be relatively fixed, and personnel entering the production site must wear disposable dust-free hats, gloves, and masks, and work clothes should be changed and washed frequently. The materials used for making should be scrubbed with alcohol or non-corrosive detergent two to three times before entering the production site for standby.
Key points for making ducts for clean room systems
The semi-finished products after processing should be scrubbed again before entering the next process. The processing of duct flanges must ensure that the flange surface is flat, the specifications must be accurate, and the flange must match the duct to ensure good sealing of the interface when the duct is combined and connected. There should be no horizontal seams at the bottom of the duct, and longitudinal seams should be avoided as much as possible. Large-sized ducts should be made of whole plates as much as possible, and the reinforcement ribs should be reduced as much as possible. If reinforcement ribs must be provided, compression ribs and internal reinforcement ribs should not be used. Duct production should use joint angles or corner bites as much as possible, and snap-on bites should not be used for clean ducts above level 6. The galvanized layer at the bite, the rivet holes, and the flange welding must be repaired for corrosion protection. The cracks on the duct joint flanges and around the rivet holes should be sealed with silicone. The duct flanges must be flat and uniform. The flange width, rivet holes, and flange screw holes must be strictly in accordance with the specifications. The inner wall of the flexible short tube must be smooth, and artificial leather or plastic can generally be used. The duct inspection door gasket should be made of soft rubber.
3. The transportation and installation of clean room air ducts are the key to ensuring cleanliness.
Preparation before installation. Before installing the clean room air conditioning system, a schedule must be made according to the main construction procedures of the clean room. The plan must be coordinated with other specialties and should be implemented strictly according to the plan. The installation of the clean room air conditioning system must first be carried out after the construction profession (including the ground, wall, floor) paint, sound absorption, elevated floor and other aspects are completed. Before installation, complete the work of duct positioning and hanging point installation indoors, and repaint the walls and floors damaged during the installation of the hanging points.
After the indoor cleaning, the system duct is transported in. During the transportation of the duct, attention should be paid to the protection of the head, and the surface of the duct should be cleaned before entering the site.
The staff participating in the installation must be showered and wear dust-free clothes, masks, and shoe covers before construction. The tools, materials, and components used must be wiped with alcohol and checked with dust-free paper. Only when they meet the requirements can they enter the construction site.
The connection of air duct fittings and components should be made while opening the head, and there should be no oil stain inside the air duct. The flange gasket should be a material that is not easy to age and has elastic strength, and straight seam splicing is not allowed. The open end should still be sealed after installation.
The air duct insulation should be carried out after the system pipeline is installed and the air leakage detection is qualified. After the insulation is completed, the room must be thoroughly cleaned.
4. Ensure the successful commissioning of the clean room air conditioning system in one time.
After the installation of the clean room air conditioning system, the air conditioning room must be cleaned and cleaned. All irrelevant objects must be removed, and the paint on the walls, ceilings and floors of the air conditioning room and the room must be carefully checked for damage and repair. Carefully check the filtration system of the equipment. For the end of the air supply system, the air outlet can be directly installed (the system with cleanliness ISO 6 or above can be installed with hepa filters). Carefully check the electrical, automatic control system, and power supply system. After confirming that each system is intact, the test run can be carried out.
Develop a detailed test run plan, arrange the personnel participating in the test run, and prepare the necessary tools, instruments, and measuring tools.
The test run must be carried out under unified organization and unified command. During the trial operation, the fresh air filter should be replaced every 2 hours, and the end equipped with hepa filters should be replaced and cleaned regularly, generally once every 4 hours. The trial operation must be carried out continuously, and the operation status can be understood from the automatic control system. The data of each air conditioning room and equipment room, and the adjustment is implemented through the automatic control system. The time for the clean room air commissioning must comply with the time specified in the specification.
After the trial operation, the system can be tested for various indicators after reaching stability. The test content includes air volume (air velocity), static pressure difference, air filter leakage, indoor air cleanliness level, indoor floating bacteria and sedimentation bacteria, air temperature and humidity, indoor air flow shape, indoor noise and other indicators, and can also be carried out according to the design cleanliness level or the level requirements under the agreed acceptance state.
In short, to ensure the success of the construction of the clean room air conditioning system, strict material procurement and dust-free inspection of the process should be carried out. Establish various systems to ensure the construction of clean room air conditioning, strengthen the technical and quality education of construction personnel, and prepare all kinds of tools and equipment.
Post time: Feb-27-2025