Technical requirements for air ducts of clean air conditioning systems:
1. The air duct shall be made of metal materials and the bite seams shall be sealed.
2. The duct should have enough inner diameter to control the wind speed in the following range: the main duct should be 7-9 m/s.
No tuyere branch or trunk pipe 5-7m/s with tuyere branch or trunk pipe 3-5m/s
3. There should be gaskets between air duct flanges. The gaskets should be made of closed-cell sponge rubber. It is strictly prohibited to use rubber, latex sponge, polyethylene, thick cardboard and other materials with open-cell pore, dust-prone and ageing-prone. The thickness should not be less than 5 mm. No paint on the gasket.
4. There should be a flexible short pipe between the air duct and the equipment, and the appearance should not be dew. When this is possible, it should be replaced by a double-layer short pipe. The single-layer short tube must be smooth facing inward and the outer layer should be smooth facing outward when double-layer is used.
5. The flexible short tube installed in the negative pressure section should be in a tight state.
6. Mufflers and fire valves shall be installed on the air supply pipes according to the design requirements. The muffler section shall be no less than 900mm.
7. In air conditioners (boxes), there should be at least surface coolers and heaters, not without heaters (except in special dry areas such as Xinjiang). Preheaters must be provided at the entrance of air conditioners (boxes) or fresh air conditioners (boxes) in cold areas.
8. Air supply terminal filters should be sub-efficient filters or high-efficiency filters with fiberglass filter paper. Wooden frames should not be used. The folded filter core and separator must be tight and firm, and must not have obvious soft shaking phenomenon.
9. The filter at the end of the air supply should not be installed in the air conditioning box, but in the air supply outlet. If it can not be installed in the air outlet, it should be installed in the pipeline or sandwich, roof near the high-efficiency air outlet.
10. The plane diffuser used in air conditioning system should not be used in the diffuser of air supply outlet.
11. High efficiency filters and frames must be sealed. In the sealing method stipulated in the Code for Construction and Acceptance of Clean Room, the use of sealing strips should meet the requirements of 5.3. Compression bolts should be pressed at least at four corners and eight points, not only at the midpoint of each side. The filter shall not be glued only with sealant, nor shall the filter be suspended in the tuyere and glued in the air gap. All sealing methods should not hinder the removal of filters and increase the difficulty of removal.
12. In one-way flow clean room, every high-efficiency filter of air supply outlet should have a qualified report of leak detection scanned on site at the time of acceptance of the project. The report should be issued by a third party qualified inspection unit. After replacing the filter, there should be on-site scan leak detection qualified report confirmed by both the replacer and the user.
In turbulent clean rooms, the number of leak detection spot checks should reach 20% of the total number of air outlets, not less than 2. The filter that still leaks after repairing once should be replaced and recorded.
13. The air supply system for high-risk biological aerosols with class III and IV biological hazards which may occur and must be strictly prevented from cross-contamination (e.g. animal feeding rooms, biological products workshop that can not stop production) should have the function of not changing high-efficiency filters indoors and not stopping the operation of the system when changing filters.
How to Set Up the Back and Exhaust System of Air Conditioning Purification System
1. Mufflers and fire valves shall be installed on the return air duct according to the design requirements.
2. If the purified air in general clean places can be recycled, effective measures should be taken to avoid pollution and cross-contamination, and the tuyeres should have filters.
Penicillin plant and its sub-assembly workshop with independent system should have high or sub-high efficiency filters in the return air outlet of workshop under the condition of exhaust air with dust point, and low or ultra-low resistance should be preferred.
3. The upper part of the return air outlet should not exceed 500 mm and the lower part should not exceed 100 mm.
4. The grid of return air outlet should be vertical strip, and the one-way flow field should adopt the form of adjustable air volume with constant wind direction.
5. Any indoor exhaust outlet should have air filter, and its type should meet the design requirements. When the exhaust air will cause toxic and harmful effects on the environment, the indoor side of the exhaust outlet must be equipped with high-efficiency filters, followed by coarse-efficiency filters, exhaust fans and check valves. The exhaust fans should be close to the outlet, and the exhaust duct should be kept as a negative pressure pipeline. Dust removal equipment should be installed on the exhaust duct to ensure that the exhaust concentration reaches the standard.
6. The pipeline for eliminating biological aerosols which may contain Class III biological hazards must be a negative pressure pipeline formed by stainless steel welding. The filter device on the exhaust outlet must be zero leakage, and the filter is class B or higher efficient filter. High-efficiency filters should be disassembled safely.
7. In addition to meeting the requirements for removing bio-aerosols that may contain class IV biological hazards, two high-efficiency filters of class B and C must be installed. The exhaust filter device must be zero leakage, and leak detection must be on-line scanned on site.
8. Exhaust pipes with corrosive chemical aerosols shall be made of anticorrosive materials.