I. Maintain basic cognition
As the “core barrier” of the purification system, the performance of laboratory air filters directly affects air cleanliness, experimental accuracy, and personnel health. The filtration accuracy and load-carrying capacity of different types of filters (primary, medium, high efficiency/ultra-high efficiency) vary significantly, and maintenance strategies need to be formulated specifically. The core maintenance objectives are: to ensure stable filtration efficiency, extend equipment lifespan, reduce operational energy consumption, and avoid the risk of secondary pollution.
Ii. Maintenance Process by Type
(1) Primary air filters (grades G1-G4)
Applicable scenarios: Pre-filtering at the front end of the system, intercepting large particle pollutants such as dust and hair, commonly seen at the fresh air inlets of laboratories and fan coil units.
Maintenance cycle
Regular laboratory: Check once every 1 to 3 months and replace once every 3 to 6 months.
Laboratories with high dust concentration (such as sample grinding rooms) : Inspect once every two weeks and replace once every 1-2 months.
Specific operation
Inspection: Monitor the resistance through a differential pressure gauge. When the resistance reaches 1.5 to 2 times the initial resistance, immediate action is required. Visually inspect the surface of the filter screen. If there is obvious dust accumulation or damage, start maintenance.
Cleaning: It can be cleaned by reverse blowing with compressed air (pressure ≤0.3MPa, 15-20cm away from the filter screen, moving at a constant speed at a 45° Angle) or rinsing with clean water (only applicable to washable filter screens, and then dry until completely dry after rinsing).
Replacement: If the resistance still exceeds the standard after cleaning, the filter screen is damaged, or the maximum service life has been reached, the entire filter needs to be replaced. When replacing, wear dust-free gloves to avoid touching the filter surface of the filter screen with your hands. During installation, it should fit the frame tightly without any gaps or air leakage.
(2) Medium-efficiency air filters (F5-F9 grades
Applicable scenarios: It lies between the primary and high-efficiency filters, intercepting fine dust, pollen, etc., and protecting the high-efficiency filters at the back end. It is mostly used in the middle section of purification units.
Maintenance cycle
Regular laboratory: Check once every 3 to 6 months and replace once every 6 to 12 months.
Biological laboratories and chemical analysis laboratories: They should be inspected once every 2 to 3 months and replaced once every 4 to 6 months.
Specific operation
Inspection: Mainly based on pressure difference monitoring, the initial resistance is usually 50-100Pa. Maintenance is required when the resistance rises to 150-200Pa. At the same time, check whether the filter screen frame is deformed and whether the sealant is aged.
Cleaning: Only some F5-F7 grade filter screens can be cleaned. Use low-pressure compressed air to blow or neutral detergent to gently scrub. High-pressure flushing is strictly prohibited to prevent damage to the filter material. After cleaning, the filtration efficiency needs to be tested. If it drops by more than 20%, it should be discarded.
Replacement: Prioritize the replacement of filter screens with excessive resistance. During replacement, simultaneously check the sealing performance of the installation frame and replace the sealing gasket if necessary. The specifications and models of the new filter screen need to be checked to ensure they match the system.
(3) High-efficiency/ultra-high-efficiency air filters (H10-U17 grade
Applicable scenarios: Purification terminal, intercepting bacteria, viruses, ultrafine dust, etc., is a key guarantee for biosafety laboratories and clean laboratory benches.
Maintenance cycle
General clean laboratory (Class 10,000) : Inspect once every 6 to 12 months and replace once every 1 to 2 years.
High-cleanliness laboratories (Class 100 / Class 10) and biosafety level 3 laboratories: They should be inspected once every 3 to 6 months and replaced once every 6 to 12 months.
Specific operation
Inspection: Core monitoring of pressure difference and integrity. When the pressure difference rises to twice the initial resistance, an assessment and replacement are required. Integrity tests (such as PAO tests) are conducted monthly using an aerosol photometer. If leakage points are found, they should be marked and dealt with.
Replacement: High-efficiency filters must be replaced when the pressure difference exceeds the standard, the integrity test fails, the filter material is damaged, or the maximum service life is reached. Replacement should be carried out in a clean environment. Wear dust-free suits, gloves, and masks. Follow the sequence of “remove the old first and then install the new”. After the new filter is installed, an integrity test should be conducted again. Only after passing the test can it be put into operation.
Disposal: High-efficiency filters used in biological laboratories should be packaged in accordance with medical waste standards and sterilized before being discarded. Filters containing chemical pollutants need to be neutralized according to the nature of the pollutants.
Iii. Key Safeguard Measures
(1) Construction of a monitoring system
Each filter must be equipped with a differential pressure gauge and calibrated regularly (at least once a year) to ensure the accuracy of the data.
Establish an electronic ledger to record the filter model, installation date, initial resistance, data from each inspection, and maintenance records, achieving full life cycle traceability.
High-risk laboratories can be equipped with online monitoring systems to monitor resistance and cleanliness in real time and automatically alert when abnormalities occur.
(II) Personnel and Environmental Management
Maintenance personnel need to undergo professional training, be familiar with the characteristics and operation norms of different filters, and master the integrity testing methods.
Before maintenance work, the relevant fans should be turned off. The biological laboratory needs to be disinfected first to prevent the spread of pollutants.
The old filter screens after replacement should be sorted and treated. It is strictly forbidden to discard them at will to cause secondary pollution.
(3) Emergency Response mechanism
In case of sudden filter screen damage or leakage, immediately stop the machine and isolate the contaminated area. After replacing the filter screen with a new one, conduct a thorough cleaning and disinfection of the environment.
When the pressure difference drops sharply, it is necessary to check whether the filter screen is improperly installed or damaged. When the pressure difference rises sharply, it is necessary to check whether the system is clogged and deal with the problem in a timely manner.
As the “core barrier” of the purification system, the performance of laboratory air filters directly affects air cleanliness, experimental accuracy, and personnel health. The filtration accuracy and load-carrying capacity of different types of filters (primary, medium, high efficiency/ultra-high efficiency) vary significantly, and maintenance strategies need to be formulated specifically. The core maintenance objectives are: to ensure stable filtration efficiency, extend equipment lifespan, reduce operational energy consumption, and avoid the risk of secondary pollution.
Ii. Maintenance Process by Type
(1) Primary air filters (grades G1-G4)
Applicable scenarios: Pre-filtering at the front end of the system, intercepting large particle pollutants such as dust and hair, commonly seen at the fresh air inlets of laboratories and fan coil units.
Maintenance cycle
Regular laboratory: Check once every 1 to 3 months and replace once every 3 to 6 months.
Laboratories with high dust concentration (such as sample grinding rooms) : Inspect once every two weeks and replace once every 1-2 months.
Specific operation
Inspection: Monitor the resistance through a differential pressure gauge. When the resistance reaches 1.5 to 2 times the initial resistance, immediate action is required. Visually inspect the surface of the filter screen. If there is obvious dust accumulation or damage, start maintenance.
Cleaning: It can be cleaned by reverse blowing with compressed air (pressure ≤0.3MPa, 15-20cm away from the filter screen, moving at a constant speed at a 45° Angle) or rinsing with clean water (only applicable to washable filter screens, and then dry until completely dry after rinsing).
Replacement: If the resistance still exceeds the standard after cleaning, the filter screen is damaged, or the maximum service life has been reached, the entire filter needs to be replaced. When replacing, wear dust-free gloves to avoid touching the filter surface of the filter screen with your hands. During installation, it should fit the frame tightly without any gaps or air leakage.
(2) Medium-efficiency air filters (F5-F9 grades
Applicable scenarios: It lies between the primary and high-efficiency filters, intercepting fine dust, pollen, etc., and protecting the high-efficiency filters at the back end. It is mostly used in the middle section of purification units.
Maintenance cycle
Regular laboratory: Check once every 3 to 6 months and replace once every 6 to 12 months.
Biological laboratories and chemical analysis laboratories: They should be inspected once every 2 to 3 months and replaced once every 4 to 6 months.
Specific operation
Inspection: Mainly based on pressure difference monitoring, the initial resistance is usually 50-100Pa. Maintenance is required when the resistance rises to 150-200Pa. At the same time, check whether the filter screen frame is deformed and whether the sealant is aged.
Cleaning: Only some F5-F7 grade filter screens can be cleaned. Use low-pressure compressed air to blow or neutral detergent to gently scrub. High-pressure flushing is strictly prohibited to prevent damage to the filter material. After cleaning, the filtration efficiency needs to be tested. If it drops by more than 20%, it should be discarded.
Replacement: Prioritize the replacement of filter screens with excessive resistance. During replacement, simultaneously check the sealing performance of the installation frame and replace the sealing gasket if necessary. The specifications and models of the new filter screen need to be checked to ensure they match the system.
(3) High-efficiency/ultra-high-efficiency air filters (H10-U17 grade
Applicable scenarios: Purification terminal, intercepting bacteria, viruses, ultrafine dust, etc., is a key guarantee for biosafety laboratories and clean laboratory benches.
Maintenance cycle
General clean laboratory (Class 10,000) : Inspect once every 6 to 12 months and replace once every 1 to 2 years.
High-cleanliness laboratories (Class 100 / Class 10) and biosafety level 3 laboratories: They should be inspected once every 3 to 6 months and replaced once every 6 to 12 months.
Specific operation
Inspection: Core monitoring of pressure difference and integrity. When the pressure difference rises to twice the initial resistance, an assessment and replacement are required. Integrity tests (such as PAO tests) are conducted monthly using an aerosol photometer. If leakage points are found, they should be marked and dealt with.
Replacement: High-efficiency filters must be replaced when the pressure difference exceeds the standard, the integrity test fails, the filter material is damaged, or the maximum service life is reached. Replacement should be carried out in a clean environment. Wear dust-free suits, gloves, and masks. Follow the sequence of “remove the old first and then install the new”. After the new filter is installed, an integrity test should be conducted again. Only after passing the test can it be put into operation.
Disposal: High-efficiency filters used in biological laboratories should be packaged in accordance with medical waste standards and sterilized before being discarded. Filters containing chemical pollutants need to be neutralized according to the nature of the pollutants.
Iii. Key Safeguard Measures
(1) Construction of a monitoring system
Each filter must be equipped with a differential pressure gauge and calibrated regularly (at least once a year) to ensure the accuracy of the data.
Establish an electronic ledger to record the filter model, installation date, initial resistance, data from each inspection, and maintenance records, achieving full life cycle traceability.
High-risk laboratories can be equipped with online monitoring systems to monitor resistance and cleanliness in real time and automatically alert when abnormalities occur.
(II) Personnel and Environmental Management
Maintenance personnel need to undergo professional training, be familiar with the characteristics and operation norms of different filters, and master the integrity testing methods.
Before maintenance work, the relevant fans should be turned off. The biological laboratory needs to be disinfected first to prevent the spread of pollutants.
The old filter screens after replacement should be sorted and treated. It is strictly forbidden to discard them at will to cause secondary pollution.
(3) Emergency Response mechanism
In case of sudden filter screen damage or leakage, immediately stop the machine and isolate the contaminated area. After replacing the filter screen with a new one, conduct a thorough cleaning and disinfection of the environment.
When the pressure difference drops sharply, it is necessary to check whether the filter screen is improperly installed or damaged. When the pressure difference rises sharply, it is necessary to check whether the system is clogged and deal with the problem in a timely manner.
