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Introduction to Cleanroom Debugging Methods

2023-12-25

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Marya

The purpose of conducting system debugging in a cleanroom is reflected in the following aspects: Identify and resolve issues related to equipment, facilities, controls, processes, etc., to ensure the normal operation of the cleanroom; achieve the system design goal.

The purpose of conducting system debugging in a cleanroom is reflected in the following aspects:

一、Identify and resolve issues related to equipment, facilities, controls, processes, etc., to ensure the normal operation of the cleanroom; Identify issues and correct deficiencies in design and installation.
二、To achieve the system design goal of meeting the design requirements for various indicators of the internal environmental parameters of the cleanroom.
三、On the premise of meeting the design requirements of various control parameters, minimize operating costs as much as possible and ensure that the system operates in a low consumption and energy-saving state.

 


1. Equipment performance measurement and adjustment


1) Familiar with technical documents and drawings related to air conditioning systems, indoor and outdoor air calculation parameters, air volume load, temperature and humidity control accuracy requirements, and other processes;
2)Debugging personnel, together with the design, construction, and construction units, go to the site to identify areas where the installation quality of the air conditioning system is not up to standard, identify areas where construction does not match the design, record them in the list of deficiencies, and complete the modifications on time;
3)Prepare the necessary instruments, meters, tools, and relevant records for debugging;
4)After the debugging of each sub project is completed, the comprehensive performance of the air conditioning system shall be measured to determine whether the comprehensive indicators of the system's linkage operation meet the design requirements. If they do not meet the requirements, further adjustments shall be made during the measurement;
5)Test the cleanliness, temperature, humidity, and static pressure values of the clean room. If they do not meet the requirements, further adjustments are needed.

 


2. Implementation and debugging content


1)Measurement of air supply volume at each air supply outlet in the room, conversion of total air supply volume in the cleanroom, total system air supply volume, and room ventilation frequency:

 

  • Adjust and detect the air supply volume of each air supply outlet using an air volume tester, and then add up the air supply volumes of all air supply outlets in each room to obtain the air supply volume of each room. Finally, add up the air supply volumes of each room to obtain the total air supply volume of the system.
  • Divide the air supply volume of each room by its volume to determine the number of air changes in that room.
  • After testing, the air supply volume of each air supply outlet, the total air volume of the room, the total air supply volume of the system, and the number of air exchanges in the room all need to meet the design requirements.
  • Standard: Total air volume: 0-20%; Air volume at each air outlet: ± 15%; Fresh air volume: ± 10%.

 

2)Detection of static pressure difference:

 

  • The measurement of static pressure difference should be carried out after the entire connected clean room system is fully opened and running stably. All doors should be tightly closed, and the pressure measuring tube should be sealed as much as possible. The tube should be extended from the soft cushion under the door as much as possible. If the door gap is opened, it will cause a decrease in pressure difference. The measurement sequence should start from the high pressure room designed, and then proceed to the low pressure room in sequence. In terms of cleanliness level, Measurement should gradually move towards lower levels starting from higher level cleanrooms.
  • Considering that the pressure difference between different levels of clean rooms is actually small, there is a high requirement for the accuracy of micro pressure gauges. Not less than 2.0Pa. Standard: ≥ 5Pa between different levels and indoor clean and non clean areas (new version GMP ≥ 10Pa); Cleanroom and outdoor should be ≥ 10Pa.

 

 

3)Indoor cleanliness testing:

 

  • The minimum number of sampling points for measuring cleanliness shall be determined according to regulations. Each point shall be sampled no less than 3 times, and the sampling frequency of each point may vary. Condition: After adjusting the air volume and positive pressure; Indoor cleaning should be carried out according to requirements, and biological cleanrooms should be disinfected according to requirements, with sufficient pre cleaning (air blowing) time. No more than two people should enter in clean clothes and try to test in the downwind direction.

 

4)Detection of indoor planktonic and settling bacteria:

 

  • Indoor planktonic bacteria measurement points and cleanliness measurement points can be the same; Sampling should be carried out according to the steps specified in the instrument manual, and special attention should be paid to disinfecting and sterilizing the instrument before testing.
  • When measuring settling bacteria, culture dishes should be arranged in representative locations and areas with minimal airflow disturbance. The number of culture dishes can be the same as the number of indoor cleanliness sampling points, but the number of culture dishes should not be less than the relevant regulations.

 

 

5)Leakage detection of high-efficiency air filters after installation in cleanroom: 

 

  • For high-efficiency filters installed at the supply and exhaust ends, the scanning method should be used for filter installation frame and full section leakage detection. The sampling port should be placed at a distance of 50px to 75px from the surface of the tested filter, and moved at a speed of 5mm/s to 20mm/s. The entire section, head adhesive, and installation frame of the tested filter should be scanned. Standard: When the reading is greater than 0.01% of the upstream aerosol concentration, there is a leakage.

 

6)Temperature and relative humidity detection: 

 

  • Before measuring the indoor air temperature and relative humidity, the purification air conditioning system should have been running continuously for at least 24 hours. For places with constant temperature requirements, according to the requirements for temperature and relative humidity fluctuation range, the measurement should be carried out continuously for 8-48 hours, with intervals not exceeding 30 minutes each time. According to the fluctuation range of temperature and relative humidity, corresponding instruments with sufficient accuracy should be selected for measurement.