Modular cleanroom routine maintenance: 5 simple steps to extend service life
This article focuses on five core and easy-to-operate maintenance points, combining industry professional standards to explain practical methods and precautions, helping relevant practitioners to carry out maintenance work efficiently and reduce operation and maintenance costs.
I. FFU Filter Replacement: Safeguarding the First Line of Defense for Cleanliness
As a core purification component of modular cleanrooms, the cleanliness of the FFU (Fan Filter Unit) filter directly affects the concentration of suspended particles in the indoor air, which is crucial for maintaining the cleanliness level. After long-term use, the filter will become clogged with dust and particulate matter, leading to reduced airflow, increased energy consumption, and even filter damage and contaminant leakage. Therefore, regular filter replacement is of paramount importance in maintenance.
From a professional standard perspective, FFU filter replacement should follow the principle of "graded replacement and adjustment as needed." The specific cycle and operating procedures are as follows:
Primary filter: Replacement cycle is 1-3 months. If the dust concentration around the cleanroom is high (e.g., near production workshops or main traffic routes), it should be shortened to less than 1 month. When replacing the FFU, turn off the power. After opening the panel, gently remove the old filter to avoid dust scattering. When installing the new filter, ensure it fits tightly against the frame without gaps to prevent unfiltered air from entering the room.
Medium-efficiency filter: Replace every 6-12 months. Before replacement, use a vacuum cleaner to clean the inside of the FFU to prevent dust from contaminating the new filter when removing the old one. After installation, check that the filter clips are secure to prevent displacement during operation.
High-efficiency HEPA filter: Replace every 18-24 months. After replacement, perform a leak test (e.g., PAO leak test) to confirm there are no leaks before restarting the FFU. If the cleanroom is used in a high-cleanliness environment (e.g., Class 100, Class 1000), check the filter pressure differential every 6 months. Replace the filter when the pressure differential exceeds 20% of the initial value.
Note: Used filters must be sealed and packaged and disposed of according to hazardous waste regulations to prevent secondary dust contamination.
II. Wall Panel Cleaning: Balancing Cleanliness and Structural Protection
The wall panels of modular cleanrooms (commonly color steel sandwich panels or stainless steel panels) are crucial for maintaining the room's airtightness and cleanliness. Their surfaces easily accumulate dust and stains. Improper cleaning can not only affect cleanliness but also lead to coating peeling, corrosion, and shortened lifespan. Cleaning should adhere to the principles of "gentle, residue-free, and non-damaging," avoiding the use of corrosive cleaners or rough tools.
Professional cleaning methods are as follows:
1. Daily Cleaning: Use a clean, lint-free cloth dampened with a neutral detergent (such as medical alcohol or a specialized cleanroom cleaner) to gently wipe the wall panel surface daily. Pay special attention to cleaning corners, seams, and door/window frames where dust easily accumulates, avoiding water residue.
2. Regular Deep Cleaning: Perform a deep cleaning monthly. For stubborn stains, first apply a small amount of detergent to a lint-free cloth and let it soak for 1-2 minutes, then gently wipe. Do not scrape vigorously to prevent damage to the wall panel coating.
3. Special Cleaning: If the wall panel surface is contaminated with chemicals or oil, wipe it clean immediately with a lint-free cloth, then wash with a neutral detergent to avoid chemical corrosion. Stainless steel wall panels can be polished periodically with a stainless steel-specific cleaner to maintain surface shine and prevent oxidation.
Additional Notes: During cleaning, avoid getting cleaning agents into wall panel joints and electrical interfaces to prevent damage to sealant and electrical components. After cleaning, ventilate the room for 30 minutes to ensure there is no residual cleaning agent odor.
III. Regular Calibration of Differential Pressure/Temperature and Humidity: Maintaining Stable Cleanroom Operation
The differential pressure, temperature, and humidity of a modular cleanroom are core parameters for ensuring cleanliness and the stability of the production environment. If these parameters deviate from standards, outdoor contaminants may seep in, products may become damp and deteriorate, personnel comfort may decrease, and even production process compliance may be affected. Therefore, regularly calibrating differential pressure gauges and temperature and humidity sensors to ensure accurate parameters is a crucial part of daily maintenance.
Professional calibration specifications are as follows:
Differential Pressure Calibration: Calibrate the differential pressure gauge monthly. The calibration tool must be a standard differential pressure gauge that has been metrologically certified. Before calibration, close the cleanroom doors and windows, and turn on all FFUs and exhaust systems to achieve a stable pressure difference (typically, the pressure difference between the cleanroom and non-clean area should be ≥10Pa, but this varies depending on the cleanliness level). Connect the standard differential pressure gauge in parallel with the indoor differential pressure gauge and compare the readings. If the deviation exceeds ±5%, adjust the differential pressure gauge calibration knob until the readings match. A third-party calibration by a professional metrology institution is required every six months to ensure data compliance.
Temperature and Humidity Calibration: Calibrate the temperature and humidity sensors quarterly using a standard temperature and humidity gauge. Before calibration, ensure the cleanroom is in a stable operating state. Place the standard temperature and humidity gauge and the sensor in the same location (avoiding air vents, corners, and other areas prone to error). After 30 minutes, compare the readings. If the temperature deviation exceeds ±0.5℃ or the humidity deviation exceeds ±5%RH, calibration adjustment is required. After calibration, record the calibration data and establish a calibration file for traceability.
Note: During calibration, avoid touching the sensor probe to prevent damage. After calibration, restart the monitoring system and confirm that the parameters are displayed correctly.
IV. Personnel Entry and Exit Regulations: Reducing Human-Induced Contamination and Protecting the Clean Environment
Personnel entry and exit are one of the main sources of contamination in modular cleanrooms. Dust, hair, sweat, etc., carried by the human body, if not properly treated, will directly affect the cleanliness of the room. In the long run, this will also increase the load on filters, contaminate wall panels and equipment, and shorten the lifespan of the cleanroom. Therefore, strictly enforcing personnel entry and exit regulations is a crucial but easily overlooked aspect of daily maintenance.
Professional entry and exit regulations are as follows:
1. Entry Procedure: Personnel must first change into cleanroom suits, cleanroom shoes, cleanroom caps, and masks in the changing area, ensuring that hair, clothing, and shoes are completely covered and not exposed. Then, enter the air shower room and turn on the air shower system (air shower time ≥ 30 seconds) to remove surface dust. Only after the air shower is completed can personnel enter the cleanroom. It is forbidden to bring mobile phones, keys, cosmetics, or other unnecessary items.
2. Exit Procedure: When leaving the cleanroom, personnel must first remove their cleanroom suits, cleanroom shoes, etc., in the buffer room and place them in the designated cleaning container. Do not leave them haphazardly. After leaving, promptly close the cleanroom doors and windows to prevent outside air from entering.
3. Prohibitions: Personnel who have not changed clothes or undergone air showers according to regulations are prohibited from entering the cleanroom; eating, smoking, and horseplay are prohibited in the cleanroom; wearing cleanroom suits into non-clean areas is prohibited to avoid cross-contamination; cleanroom suits must be washed and disinfected regularly (at least once a week), and replaced promptly if damaged.
V. Other Key Maintenance: Details Determine Lifespan
In addition to the above four core operations, the following maintenance details are equally important and can effectively extend the lifespan of the modular cleanroom:
Sealant Maintenance: Inspect the sealant at wall panels, doors, windows, and pipe joints monthly. If cracking, peeling, or aging of the sealant is found, clean the old sealant promptly and reapply dedicated cleanroom sealant to ensure indoor airtightness and prevent external pollutants from seeping in and indoor air leakage.
Equipment Inspection: Inspect FFU fans, exhaust systems, lighting equipment, etc., weekly. Check whether the fans are operating normally and without abnormal noises, whether the exhaust ducts are blocked, and whether the lighting is intact; if any abnormalities are found, stop the machine immediately for repair to avoid equipment failure affecting cleanroom operation and reduce equipment wear and tear.
Floor Cleaning and Maintenance: Clean the floor daily with a lint-free mop and neutral detergent to avoid water accumulation and stain residue. Inspect the floor coating monthly; repair any wear or damage promptly to prevent dust and protect the floor structure.
Conclusion: The core of daily maintenance for modular cleanrooms lies in "regularity, standardization, and meticulousness." The five simple operations mentioned above, requiring no complex professional equipment, effectively maintain the cleanroom's cleanliness level, reduce equipment wear and tear, and extend its lifespan. It's important to note that the maintenance cycle and standards for modular cleanrooms of different industries and cleanliness levels can be adjusted according to the actual usage scenario (e.g., pharmaceutical cleanrooms must follow GMP standards, while the electronics industry requires strict control of static electricity and dust).
During daily maintenance, it is recommended to establish a comprehensive maintenance record, documenting data such as filter replacement, calibration, and cleaning, to facilitate traceability and optimize maintenance plans. Only by consistently adhering to standardized maintenance can modular cleanrooms continue to function stably, providing a reliable clean environment for production and R&D while reducing long-term operation and maintenance costs.