What i s the installation and replacement standard of HEPA filter?
In the daily maintenance of clean rooms and various clean workshops, the maintenance of air filters is a big expense, but the maintenance of air cleanliness is necessary for the production of environmental pollution requirements,
Which HEPA filter maintenance and HEPA filter installation and replacement standards are what? At ordinary times, the air filter, especially the high efficiency air filter packaging, transportation, installation and use process, should be in accordance with the high efficiency filter manufacturer’s standard requirements, in order to ensure the use of high efficiency air filter effect. Each type of air filter in use for a period of time, because of the filter material surface collected a variety of dust, so that the air filter efficiency and air filter resistance decline, affecting the central air conditioning unit or clean engineering supporting efficient air supply outlet air supply volume, cleanliness and efficiency, the need to replace the air filter in time to ensure the air cleanliness requirements.
1. Before installation of all kinds of air filters and high efficiency air filters, it is not allowed to tear or open the packaging bag or packaging film by hand; The air filter should be stored in strict accordance with the direction standard marked on the packing box of the HEPA filter; In the handling process of the HEPA filter, it should be handled lightly and put lightly to avoid violent vibration and collision.
2. For HEPA filters, the installation direction must be correct: when the filter is installed vertically with corrugated plate, the corrugated plate must be perpendicular to the ground; The connection between the vertical filter and the frame is strictly prohibited from leakage, deformation, damage and glue leakage. After installation, the inner wall must be clean, without dust, oil, rust and debris.
3. Inspection method: observation or white silk wipe inspection.
4. Before the installation of HEPA filter, the clean room must be comprehensively cleaned and wiped. If there is dust accumulation inside the air conditioning system, it should be cleaned and wiped again to meet the cleaning requirements. If the high efficiency filter is installed in the technical sandwich or the ceiling, the technical layer or the ceiling should also be comprehensively cleaned and wiped.
5. The transportation and storage of HEPA filters should be shelved in accordance with the direction of the manufacturer’s signs. In the process of transportation, should be handled lightly, to prevent violent vibration and collision, can not be forced to load and unload.
6. Before installation, the HEPA filter (HEPA filters manufacturer’s)must be unpacked at the installation site for appearance inspection, including: filter paper, sealant and frame damage; Whether the side length, diagonal and thickness dimensions meet the requirements; The frame has burrs and rust spots (metal frame); Whether the product certificate, technical performance meets the design requirements. Then the inspection shall be carried out in accordance with the method specified in the national standard “Clean Room Construction and Acceptance Code” (JGJ71-90), and the qualified ones shall be installed immediately.
7. Hepa filters with cleanliness level equal to or higher than 100 for clean rooms should be leak detected according to the method specified in the “Code for Construction and Acceptance of Clean Rooms” (JGJ71-90) before installation, and meet the specified requirements.
8. When installing the HEPA filter, the arrow on the outer frame should be consistent with the air flow direction; When it is installed vertically, the filter paper crease direction should be perpendicular to the ground.
9. Install coarse effect flat plate or folding filter, should make the galvanized net surface in the direction of the back of the air outlet. When installing the bag filter, the length direction of the filter bag should be perpendicular to the ground, and the direction of the filter bag should not be parallel to the ground.
10 under normal use conditions, flat plate, folding coarse or medium effect filter, generally 1 to 3 months to replace once, the requirements of the area is not strict, the filter material can be replaced with clean water can be soaked, washed, and then cool dry to replace; Generally, after washing 1-2 times, a new filter must be replaced to ensure filtration efficiency.
11. For the bag type coarse effect or medium effect filter, under normal conditions of use (average 8 hours a day, continuous operation), the general use of 7-9 weeks should be replaced.
12. For subHEPA filters, under normal use conditions (average 8 hours a day, continuous operation), generally used for 5 to 6 months, should also be replaced.
13. For the above filter, if there is a differential pressure gauge or differential pressure sensor before and after the filter, the coarse filter, when the differential pressure value is greater than 250Pa, must be replaced; For the medium effect filter, the pressure difference is greater than 330Pa, must be replaced; For the subHEPA filter, when the pressure difference is greater than 400Pa, it must be replaced, and the original filter can not be reused;
14. For HEPA filter, when the filter resistance value is greater than 450Pa; Or when the airflow velocity on the outlet surface is reduced to the minimum, the airflow velocity can not be increased even after the replacement of the coarse effect and medium effect filter; Or when the surface of the HEPA filter can not be repaired leakage situation, must be replaced with a new HEPA filter; If there is no such condition, it can be replaced once every 1-2 years according to the use of environmental conditions.
15. In order to give full play to the role of the filter, in the selection and use process, the headwind speed of the filter, coarse effect, medium effect filter should not be greater than 2.5m/s, subhePA filter and HEPA filter should not be greater than 1.5m/s, which is not only conducive to ensure the efficiency of the filter, but also can extend the service life of the filter, save costs.
16. When the equipment is running, generally do not replace the filter; If the filter can not be stopped for replacement because it has reached the replacement deadline, only the coarse and medium effect filter is allowed to be replaced without stopping the fan; Subhepa filter and HEPA filter must stop air supply before replacement.
17. The gasket between the filter and the connecting frame must be tight and leak-free to ensure the filtering effect.
18. For HEPA filters that need to be used in high humidity and temperature environments, filter paper with high temperature and humidity resistance, separator and frame materials must be selected to meet production requirements.
19 Biological clean room and clean room, must choose the filter of metal frame, and its surface should not be easy to rust, do not allow the use of
wood frame plate filter, in order to prevent bacteria, affect the qualified product.