Analysis of Final Acceptance Items for Cleanrooms
2025.01.13
Cleanrooms are special facilities with extremely strict environmental requirements. The final acceptance work for cleanrooms is of utmost importance. It directly affects whether the workshop can be put into normal use and the quality and safety of subsequent production activities. As a professional manufacturer of purification equipment, Guangzhou Cleanroom Construction Co., Ltd. has rich experience in the construction of cleanrooms. Today, we will deeply analyze the key items for the final acceptance of cleanrooms.
I. Acceptance of the Air Purification System
(I) Filter Performance Testing
- Filtration Efficiency：High - Efficiency Particulate Air (HEPA) filters and Ultra - Low - Penetration Air (ULPA) filters are the core components of air purification in cleanrooms. During the acceptance process, professional testing equipment such as particle counters should be used to test the filtration efficiency of the filters. For example, for HEPA filters, it is necessary to ensure that the filtration efficiency for particles with a particle size of 0.3 microns reaches over 99.97%. If the filtration efficiency does not meet the standard, there will be too many dust particles in the workshop, affecting product quality.
- Integrity Testing：Methods such as scanning tests are used to check whether there are any breakages or leaks in the filters. Even a tiny hole may allow unfiltered air to enter the workshop and damage the clean environment. Once a problem with the filter is detected, it must be replaced in a timely manner to ensure the normal operation of the air purification system.
(II) Air Volume and Air Velocity Testing
- Air Supply Volume：An appropriate air supply volume is the basis for maintaining the cleanliness of the workshop. During the acceptance, measure the air volume of each air supply outlet to ensure that the total air supply volume meets the design requirements. Insufficient air supply volume cannot effectively dilute the pollutants in the workshop; excessive air supply volume may cause energy waste and air flow turbulence in the workshop.
- Air Velocity：Test the air velocity in key areas of the room, such as the working area and near the air return vents. Different levels of cleanrooms have different requirements for air velocity. For example, the air velocity in general clean areas should be maintained at 0.25 - 0.35 m/s. Uneven air velocity or air velocity not in line with the standard will affect the air circulation and the discharge effect of pollutants.
(III) Pressure Difference Testing
There needs to be a certain pressure difference between different areas in the cleanroom to prevent the diffusion of pollutants. During the acceptance, test the pressure difference between the clean area and the non - clean area, as well as between different clean - level areas. Usually, the clean area should maintain a positive pressure of not less than 10 Pa relative to the non - clean area; the pressure difference between adjacent different clean - level areas should be not less than 5 Pa. Through reasonable pressure - difference settings, a trend of air flow from high - clean - level areas to low - clean - level areas is formed to avoid cross - contamination.
II. Acceptance of Temperature and Humidity Control
(I) Temperature Testing
According to the production process requirements of the workshop, conduct multi - point temperature testing in the workshop during the acceptance. For example, in the cleanroom for electronic chip manufacturing, the temperature generally needs to be controlled at 22±2°C. Too high or too low a temperature may affect the performance and production efficiency of the products. Through temperature sensors installed in the workshop, real - time temperature data is monitored and compared with the design requirements to ensure that the temperature is controlled within a reasonable range.
(II) Humidity Testing
Humidity is also crucial for the production of some products. For example, in a pharmaceutical production workshop, the humidity is usually controlled between 45% - 65%RH. Excessive humidity is likely to breed microorganisms and affect the quality of drugs; too low humidity may generate static electricity and cause damage to electronic products. Use high - precision humidity testing instruments to test the humidity at different positions in the workshop to ensure that the humidity meets the production requirements.
III. Microbial Testing
(I) Floating Bacteria Testing
Use a floating bacteria sampler to sample at different heights and in different areas of the workshop. After sampling, cultivate the collected samples and calculate the number of floating bacteria per unit volume of air. Different clean - level workshops have clear regulations on the allowable limits of floating bacteria. For example, the number of floating bacteria in a Class 100 cleanroom shall not exceed 5 CFU/m³. If the number of floating bacteria exceeds the standard, it indicates a high risk of microbial contamination in the workshop, which may affect the sterility and quality of products.
(II) Settling Bacteria Testing
Place petri dishes in the workshop to allow microorganisms in the air to naturally settle on the culture medium. After a certain period of cultivation, count the number of colonies on the petri dishes. Settling bacteria testing can reflect the settlement of microorganisms in the workshop and also needs to meet the corresponding clean - level standards. For example, the number of settling bacteria in a Class 10,000 cleanroom shall not exceed 10 CFU/dish (30 minutes).
IV. Acceptance of Lighting and Electrostatic Protection
(I) Lighting Testing
- Illuminance Testing：Use an illuminance meter to measure the illuminance of each working area in the workshop. Appropriate illuminance can ensure that operators can clearly carry out production operations, improving work efficiency and quality. Generally, the illuminance requirements for cleanrooms are between 300 - 500 lx, and the specific value depends on the production process and operation requirements.
- Lighting Uniformity：In addition to the illuminance value, also pay attention to the lighting uniformity. Avoid situations where some areas are too bright or too dark, and ensure that the light is evenly distributed throughout the workshop to reduce visual fatigue.
(II) Electrostatic Protection Testing
- Grounding Resistance Testing：Equipment, workbenches, floors, etc. in the cleanroom all need to be well - grounded to prevent the accumulation of static electricity. During the acceptance, test the grounding resistance to ensure that it meets relevant standards. Generally, the grounding resistance is required to be no greater than 4Ω.
- Effect Testing of Electrostatic Eliminators：For workshops equipped with electrostatic eliminators, test the effect of static electricity elimination. Use equipment such as electrostatic testers to measure the electrostatic voltage on the surface of objects and check whether the electrostatic elimination equipment can effectively reduce the electrostatic level and protect products from electrostatic damage.
Guangzhou Cleanroom Construction Co., Ltd. has a professional technical team that can provide comprehensive support and guidance for the final acceptance of your cleanroom. From the installation and commissioning of purification equipment to the testing of various acceptance indicators, we can ensure compliance with high standards. If you have any questions or needs regarding the final acceptance of cleanrooms, please feel free to contact us at any time. Let's work together to create a high - quality clean production environment.
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