Core precautions for the installation and maintenance of laminar flow hoods
The installation standardization of laminar flow hoods directly determines their cleaning effect and operational stability, while the scientific maintenance affects the service life and compliance of the equipment. It is necessary to strictly follow industry standards and equipment technical requirements. The specific precautions are as follows:
I. Installation Precautions
(1) Preparations before installation
Environmental and site verification: Confirm that the installation area (such as a clean workshop in a pharmaceutical factory or a laboratory) has reached the preset cleanliness level (typically 10,000/100,000 grades), with a flat floor, no dust pollution, and well-sealed walls/ceilings to prevent external contaminants from seeping in. Reserve sufficient installation space to ensure that the distance between the laminar flow hood’s air outlet and the operating table surface meets the requirements (generally 300-500mm, specifically as per the equipment manual), and at the same time, reserve a maintenance passage (≥600mm) for subsequent maintenance.
Equipment and accessories inspection: After opening the box, check whether the main body of the laminar flow hood, HEPA/ULPA filters, fans, control systems, sealing strips, and other accessories are complete, and whether there are any dents or deformations on the appearance. Check whether the filter screen is intact (without damage or odor), whether the fan impeller is stuck, whether the electrical components are firmly connected, and whether the attached certificate of conformity and test report are complete.
Technical parameter confirmation: Verify the airflow direction (vertical/horizontal), rated air volume, cleanliness grade, and other parameters of the laminar flow hood according to the design plan to ensure they match the production requirements. Confirm that the power supply conditions (voltage, power) at the installation location meet the equipment requirements, and the grounding system is reliable (grounding resistance ≤4Ω).
(2) Installation process specifications
Fixation and sealing
The hoisting type laminar flow hood should use lifting gear with a load-bearing capacity meeting the standard (≥ 1.5 times the weight of the equipment), and the levelness error should be ≤0.5‰ to avoid vibration during operation. The floor-standing type should be fixed on the anti-slip base to ensure the body is stable and does not shake.
The connection points between the laminar flow hood and the ceiling, walls, or equipment should be filled with particle-free and clean-resistant sealant (such as silicone sealant) to prevent air leakage through the gaps and avoid the mixture of non-clean air.
Airflow and pressure difference control
After installation, adjust the air velocity at the outlet to the designed range (generally 0.36-0.54m/s) to ensure that the unidirectional airflow evenly covers the operation area without vortices or dead corners. By adjusting the return air valve, a reasonable pressure difference (positive pressure ≥10Pa) is maintained between the interior of the laminar flow hood and the surrounding environment to prevent external contamination from entering.
Installation of electrical and control systems
Wiring must be carried out by professional electricians, strictly distinguishing between phase wire, neutral wire, and ground wire to avoid equipment failure caused by incorrect connections. The control system (such as wind speed display, filter screen pressure difference alarm, start-stop button) should be installed in a position that is convenient for operation and observation. The terminal blocks should be sealed and protected to prevent electrical contamination in the clean area.
On-site cleanliness protection
During the installation process, the air outlet of the laminar flow hood and the surface of the filter screen need to be covered and protected to prevent construction dust pollution. Installation tools must be cleaned. Welding, cutting, and other dust-generating operations are strictly prohibited in the clean area.
(3) Acceptance after installation
Conduct cleanliness testing (using A particle counter) to confirm that the number of particles ≥0.5μm in the operation area meets the A/B grade cleanliness requirements, and the microbial indicators are up to standard.
The test parameters, such as wind speed uniformity (wind speed deviation at each measurement point ≤±10%), noise (≤65dB (A)), and vibration, comply with the equipment technical standards.
Verify that the control system functions properly, such as wind speed regulation, differential pressure alarm, and filter screen replacement prompt, are all effective.
Sort out the installation records and inspection reports, file and keep them as proof of compliance.
Ii. Maintenance Precautions
(1) Daily Maintenance (Daily/Weekly)
Appearance and environmental cleanliness
Every day, use a lint-free cloth dipped in neutral detergent to wipe the surface of the laminar flow hood and the air outlet grille to remove dust and stains, and avoid dust accumulation affecting the airflow.
Keep the installation area clean and tidy. Do not stack any miscellaneous items. Ensure that the return air passage is unobstructed and unobstructed.
Operation parameter monitoring
Record data such as wind speed, pressure difference, temperature, and humidity every day. If the wind speed is 10% lower than the set value or the pressure difference exceeds the alarm threshold (generally, the initial pressure difference of the HEPA filter is + 50Pa), the cause should be investigated in time.
Check the operation status of the fan every week. There should be no abnormal noise or vibration, and the electrical circuits should not be loose or overheated.
Safety protection inspection
Confirm the reliability of the grounding system and the normal function of the emergency stop button every week.
For laminar flow hoods used in the production of highly active drugs, check the effect of the airflow barrier to prevent drug leakage.
(2) Regular maintenance (monthly/quarterly/annual)
Filter screen maintenance
Primary filter (pre-installed) : Clean once a month (washable type) or replace it to prevent clogging and reduce air volume.
HEPA/ULPA filter: Check the pressure difference every quarter. Replace it in time when the pressure difference reaches twice the initial value. When replacing, it should be carried out in a clean environment, with dust-free gloves worn to prevent the filter screen from coming into contact with contaminants. After replacement, the cleanliness should be retested.
After the filter screen is replaced, the replacement time, model, and test results should be recorded, and a filter screen maintenance file should be established.
Maintenance of fans and electrical systems
Check the fan bearings every quarter and add lubricating oil as needed (food-grade/medical-grade lubricating oil should be selected) to avoid dry grinding damage.
Conduct insulation testing on the motor annually (insulation resistance ≥2MΩ), check the aging condition of electrical components, and replace damaged parts in a timely manner.
Regularly calibrate the wind speed sensor and differential pressure transmitter to ensure the accuracy of the monitoring data.
Sealing and structural inspection
Check every quarter whether the sealing rubber strips are aged or have fallen off. Replace the damaged rubber strips in time to ensure the sealing effect.
Annually inspect the fixed structure of the laminar flow hood, such as the lifting gear and base, to ensure there is no looseness or corrosion. Reinforcement should be carried out if necessary.
(3) Special Maintenance and Taboos
Environmental maintenance requirements
Maintenance operations should be carried out during production breaks to avoid affecting production. When entering the clean area for maintenance, one must wear clean suits, masks, and gloves, and abide by the management regulations of the clean area.
When replacing the filter screen or overhauling the fan, temporary protection should be provided for the operation area to prevent dust generated during maintenance from polluting the clean environment.
Taboos
Corrosive cleaning agents are prohibited from being used to clean the equipment to avoid damaging the surface coating and seals.
It is strictly prohibited to adjust the fan speed and wind speed setting values without authorization. If an adjustment is necessary, it must be confirmed by the technical department, and the cleaning effect must be re-verified.
It is strictly prohibited to block the air outlet or return air channel when the laminar flow hood is in operation to prevent equipment overload damage.
Personnel who have not received professional training are not allowed to carry out maintenance operations, especially the replacement of electrical systems and filters.
(4) Maintain and manage archives
Establish a maintenance ledger for laminar flow hoods, recording equipment model, installation date, daily inspection data, regular maintenance content, filter screen replacement records, fault handling situations, etc.
Maintenance records must be kept for at least three years after the equipment is scrapped, meeting the requirements of GMP and other compliance verifications.
Regularly analyze maintenance data and optimize the maintenance cycle, such as adjusting the replacement frequency based on the actual service life of the filter screen to reduce maintenance costs.
In conclusion, the installation of laminar flow hoods must strictly control the three core aspects of “cleanliness, sealing, and parameter compliance”. Maintenance should follow the principles of “regular monitoring, precise replacement, and full traceability”, which can not only ensure the long-term stable operation of the equipment but also meet the compliance requirements of the pharmaceutical, electronic, and other industries, maximizing the cleanliness effect and equipment value.
The installation standardization of laminar flow hoods directly determines their cleaning effect and operational stability, while the scientific maintenance affects the service life and compliance of the equipment. It is necessary to strictly follow industry standards and equipment technical requirements. The specific precautions are as follows:
I. Installation Precautions
(1) Preparations before installation
Environmental and site verification: Confirm that the installation area (such as a clean workshop in a pharmaceutical factory or a laboratory) has reached the preset cleanliness level (typically 10,000/100,000 grades), with a flat floor, no dust pollution, and well-sealed walls/ceilings to prevent external contaminants from seeping in. Reserve sufficient installation space to ensure that the distance between the laminar flow hood’s air outlet and the operating table surface meets the requirements (generally 300-500mm, specifically as per the equipment manual), and at the same time, reserve a maintenance passage (≥600mm) for subsequent maintenance.
Equipment and accessories inspection: After opening the box, check whether the main body of the laminar flow hood, HEPA/ULPA filters, fans, control systems, sealing strips, and other accessories are complete, and whether there are any dents or deformations on the appearance. Check whether the filter screen is intact (without damage or odor), whether the fan impeller is stuck, whether the electrical components are firmly connected, and whether the attached certificate of conformity and test report are complete.
Technical parameter confirmation: Verify the airflow direction (vertical/horizontal), rated air volume, cleanliness grade, and other parameters of the laminar flow hood according to the design plan to ensure they match the production requirements. Confirm that the power supply conditions (voltage, power) at the installation location meet the equipment requirements, and the grounding system is reliable (grounding resistance ≤4Ω).
(2) Installation process specifications
Fixation and sealing
The hoisting type laminar flow hood should use lifting gear with a load-bearing capacity meeting the standard (≥ 1.5 times the weight of the equipment), and the levelness error should be ≤0.5‰ to avoid vibration during operation. The floor-standing type should be fixed on the anti-slip base to ensure the body is stable and does not shake.
The connection points between the laminar flow hood and the ceiling, walls, or equipment should be filled with particle-free and clean-resistant sealant (such as silicone sealant) to prevent air leakage through the gaps and avoid the mixture of non-clean air.
Airflow and pressure difference control
After installation, adjust the air velocity at the outlet to the designed range (generally 0.36-0.54m/s) to ensure that the unidirectional airflow evenly covers the operation area without vortices or dead corners. By adjusting the return air valve, a reasonable pressure difference (positive pressure ≥10Pa) is maintained between the interior of the laminar flow hood and the surrounding environment to prevent external contamination from entering.
Installation of electrical and control systems
Wiring must be carried out by professional electricians, strictly distinguishing between phase wire, neutral wire, and ground wire to avoid equipment failure caused by incorrect connections. The control system (such as wind speed display, filter screen pressure difference alarm, start-stop button) should be installed in a position that is convenient for operation and observation. The terminal blocks should be sealed and protected to prevent electrical contamination in the clean area.
On-site cleanliness protection
During the installation process, the air outlet of the laminar flow hood and the surface of the filter screen need to be covered and protected to prevent construction dust pollution. Installation tools must be cleaned. Welding, cutting, and other dust-generating operations are strictly prohibited in the clean area.
(3) Acceptance after installation
Conduct cleanliness testing (using A particle counter) to confirm that the number of particles ≥0.5μm in the operation area meets the A/B grade cleanliness requirements, and the microbial indicators are up to standard.
The test parameters, such as wind speed uniformity (wind speed deviation at each measurement point ≤±10%), noise (≤65dB (A)), and vibration, comply with the equipment technical standards.
Verify that the control system functions properly, such as wind speed regulation, differential pressure alarm, and filter screen replacement prompt, are all effective.
Sort out the installation records and inspection reports, file and keep them as proof of compliance.
Ii. Maintenance Precautions
(1) Daily Maintenance (Daily/Weekly)
Appearance and environmental cleanliness
Every day, use a lint-free cloth dipped in neutral detergent to wipe the surface of the laminar flow hood and the air outlet grille to remove dust and stains, and avoid dust accumulation affecting the airflow.
Keep the installation area clean and tidy. Do not stack any miscellaneous items. Ensure that the return air passage is unobstructed and unobstructed.
Operation parameter monitoring
Record data such as wind speed, pressure difference, temperature, and humidity every day. If the wind speed is 10% lower than the set value or the pressure difference exceeds the alarm threshold (generally, the initial pressure difference of the HEPA filter is + 50Pa), the cause should be investigated in time.
Check the operation status of the fan every week. There should be no abnormal noise or vibration, and the electrical circuits should not be loose or overheated.
Safety protection inspection
Confirm the reliability of the grounding system and the normal function of the emergency stop button every week.
For laminar flow hoods used in the production of highly active drugs, check the effect of the airflow barrier to prevent drug leakage.
(2) Regular maintenance (monthly/quarterly/annual)
Filter screen maintenance
Primary filter (pre-installed) : Clean once a month (washable type) or replace it to prevent clogging and reduce air volume.
HEPA/ULPA filter: Check the pressure difference every quarter. Replace it in time when the pressure difference reaches twice the initial value. When replacing, it should be carried out in a clean environment, with dust-free gloves worn to prevent the filter screen from coming into contact with contaminants. After replacement, the cleanliness should be retested.
After the filter screen is replaced, the replacement time, model, and test results should be recorded, and a filter screen maintenance file should be established.
Maintenance of fans and electrical systems
Check the fan bearings every quarter and add lubricating oil as needed (food-grade/medical-grade lubricating oil should be selected) to avoid dry grinding damage.
Conduct insulation testing on the motor annually (insulation resistance ≥2MΩ), check the aging condition of electrical components, and replace damaged parts in a timely manner.
Regularly calibrate the wind speed sensor and differential pressure transmitter to ensure the accuracy of the monitoring data.
Sealing and structural inspection
Check every quarter whether the sealing rubber strips are aged or have fallen off. Replace the damaged rubber strips in time to ensure the sealing effect.
Annually inspect the fixed structure of the laminar flow hood, such as the lifting gear and base, to ensure there is no looseness or corrosion. Reinforcement should be carried out if necessary.
(3) Special Maintenance and Taboos
Environmental maintenance requirements
Maintenance operations should be carried out during production breaks to avoid affecting production. When entering the clean area for maintenance, one must wear clean suits, masks, and gloves, and abide by the management regulations of the clean area.
When replacing the filter screen or overhauling the fan, temporary protection should be provided for the operation area to prevent dust generated during maintenance from polluting the clean environment.
Taboos
Corrosive cleaning agents are prohibited from being used to clean the equipment to avoid damaging the surface coating and seals.
It is strictly prohibited to adjust the fan speed and wind speed setting values without authorization. If an adjustment is necessary, it must be confirmed by the technical department, and the cleaning effect must be re-verified.
It is strictly prohibited to block the air outlet or return air channel when the laminar flow hood is in operation to prevent equipment overload damage.
Personnel who have not received professional training are not allowed to carry out maintenance operations, especially the replacement of electrical systems and filters.
(4) Maintain and manage archives
Establish a maintenance ledger for laminar flow hoods, recording equipment model, installation date, daily inspection data, regular maintenance content, filter screen replacement records, fault handling situations, etc.
Maintenance records must be kept for at least three years after the equipment is scrapped, meeting the requirements of GMP and other compliance verifications.
Regularly analyze maintenance data and optimize the maintenance cycle, such as adjusting the replacement frequency based on the actual service life of the filter screen to reduce maintenance costs.
In conclusion, the installation of laminar flow hoods must strictly control the three core aspects of “cleanliness, sealing, and parameter compliance”. Maintenance should follow the principles of “regular monitoring, precise replacement, and full traceability”, which can not only ensure the long-term stable operation of the equipment but also meet the compliance requirements of the pharmaceutical, electronic, and other industries, maximizing the cleanliness effect and equipment value.
