News Center
Your current location：Home > News CenterNews Center
Ventilation design for cleanrooms
2025/8/29
During the production process of various electronic products, it is inevitable that all kinds of dust, harmful gases and harmful substances will be discharged. An effective way to prevent their spread and contamination in the clean room is to adopt local exhaust ventilation at the relevant equipment, and then discharge the treated air to the outside after meeting the standards. The local drainage system should be set up independently for the following situations:
The exhaust medium, when mixed, can cause increased corrosiveness, toxicity, and the risk of combustion and explosion. The toxicity of the exhaust medium varies greatly between toxic and non-toxic ones. Flammable, explosive and general exhaust ventilation; When designing the exhaust system of a cleanroom, the following technical measures should be adopted. To prevent outdoor air from flowing back into the room, causing pollution and dust accumulation, common anti-backflow measures are:
Set the medium-efficiency filter; Check valves are adopted, which are convenient to use but have poor sealing performance. It adopts a sealed valve with good sealing performance, but the structure is complex. Adopt automatic control devices, etc. In addition, local exhaust systems containing flammable and explosive substances should adopt fire prevention and explosion prevention measures that are commensurate with the discharged substances. When the concentration and emission volume of harmful substances in the exhaust medium exceed the national or regional regulations on the concentration and emission volume of harmful substances, harmless treatment should be carried out. Only after meeting the standards can it be discharged into the atmosphere. For exhaust systems containing water vapor and condensing substances, slopes and exhaust outlets should be provided to promptly remove the condensate.
Ventilation measures should be taken for production auxiliary rooms such as shoe-changing, outerwear storage, washing, toilets and bathing in clean workshops. The static pressure value inside these rooms should be lower than that in clean areas.
Cleanrooms should be equipped with emergency exhaust systems in accordance with the requirements of the production process. The accident exhaust system should be equipped with automatic and manual control switches. The manual control switches should be respectively set at convenient operation locations in the clean room and outside the clean room. Generally, for clean rooms (areas) that may emit harmful gases or flammable and explosive gases, emergency exhaust devices should be installed.
The manufacturing materials, insulation materials and coatings of the equipment, pipelines and accessories of the exhaust system should be selected based on the nature and state of the discharged gas and other conditions. Generally, they should meet the following requirements:
The air ducts of the exhaust system should be made of non-combustible materials. The non-combustible materials referred to here are various types of metal plates, including carbon steel, stainless steel, and non-ferrous metal plates. The selection should be determined based on the nature of the exhaust gas. Air ducts for discharging corrosive gases should be made of corrosion-resistant and flame-retardant materials. The refractory materials referred to here mainly include fiberglass reinforced plastic with an oxygen index equal to or greater than 32. Accessories, insulation materials, sound-absorbing materials and coatings, etc. are all made of non-combustible or flame-retardant materials. The non-combustible materials referred to here mainly include rock wool, glass wool, etc. Flame-retardant materials mainly include rubber and plastic sponges, polyurethane, etc. with an oxygen index of 32 or more.
2. Smoke exhaust and prevention design for cleanrooms
A cleanroom is a closed room without Windows or with fixed Windows. Installing a smoke exhaust and prevention system is one of the necessary methods to ensure the evacuation of personnel. Article 6.5.7 of the "Code for Design of Clean Rooms" (GB50073-2001) stipulates that mechanical smoke prevention and exhaust facilities should be set up in the evacuation corridors of clean rooms. The following is an excerpt of the relevant provisions from the draft revision of the "Code for Fire Protection Design of Buildings" for your reference.Determination of smoke exhaust volume: In places where mechanical smoke exhaust facilities are installed, the smoke exhaust volume of the smoke exhaust fan, when it is responsible for the smoke exhaust of one smoke prevention area, should be no less than 60m ³ /h/m ² for calculation of the smoke exhaust volume. When a smoke exhaust system is responsible for two or more smoke compartments, the smoke exhaust volume should be calculated based on the area of the largest smoke compartment not being less than 120 m ³ /h/m ². The minimum smoke exhaust volume of a single smoke exhaust fan should not be less than 7,200 m ³ /h. The selection of smoke exhaust fans: Smoke exhaust fans can be centrifugal or dedicated smoke exhaust fans. The air volume should take into account a leakage rate of 10% to 20%, and the air pressure should meet the requirements of the most unfavorable loop of the smoke exhaust system. On the main inlet pipe of the fan, a fire damper that can automatically close when the flue gas temperature exceeds 280℃ should be installed, and it should be interlocked with the exhaust fan.
The setting of smoke exhaust outlets: Smoke exhaust outlets or smoke exhaust valves should be installed on the wall inside the ceiling, and the horizontal distance between them and the adjacent edges of the safety exits should not be less than 1.5m, and the distance from flammable objects should not be less than 1.0m. The smoke exhaust outlet or smoke exhaust valve should be kept closed at all times and equipped with manual or automatic opening devices. The maximum horizontal distance between the smoke exhaust outlet and the smoke prevention zone should not exceed 300 meters.
