Attention for HEPA filters
HEPA filter is the short name of high-efficiency air filters, is mainly used for the terminal filtration of medical, civil or industrial clean rooms with high cleanliness requirements in electronics, semiconductors, precision machinery, pharmaceuticals, hospitals, food and other industries. It's also an important part of other clean room equipments,such as FFU(Fan filter unit),HEPA box,Air shower,etc. Since HEPA filters are are generally used as the end of filtration, the special requirements for HEPA filters are also the most important.Now we are going to introduce what we should pay special attention to.
1. We need to remind customers that the most fundamental and easiest way to prolong the service life of the HEPA filtersis to keep the dust out of the pre-filter. In other words,the air should pass though pre filter and secondary filter,and then pass through HEPA filters. The pre filters are changed regularly, and it is generally not necessary to stop production or stop other normal work plans and arrangements to replace the pre-filter.
Experienced HVAC system designers will pay attention to the pre-filter. For high clean areas such as class 10000 and class 100000 clean workshops or operating rooms, F8 Air filter (Colorimetric method 95%) can be used as pre filter. In this way, the service life of the terminal HEPA filter can generally reach 5 years. F8 air filters are the most common pre filters for non-uniform flow cleanrooms. For clean workshops of class 100, class 10 or higher in chip factories, the common efficiency class of the pre filter is H10 (MPPS85%).
2. In some occasions, the regulations on the use of HEPA filters are not only based on the consideration of pressure drop or efficiecny, but also other factors. If there is hydrofluoric acid in the plant, and the workshop air conditioner is not a fresh air system, the glass fiber media of HEPA filters will be affected. Corrosion of return air will happen. For safety, the HEPA filter must be replaced regularly. For example, some hospitals and pharmaceutical factories will actively replace HEPA filters every year after the rainy season. The main purpose is to prevent any possible mold pollution on the filters. Some national tertiary first-class hospitals, biological laboratories of pharmaceutical factories, and laboratories dealing with dangerous goods will use new high-efficiency filters in order to ensure safety and reliability before launching a new important subject.
3.HEPA filter notes before installation
A. In the process of transportation, installation and use, HEPA filters must be carried out according to the requirements to ensure the use effect. After various filters have been used for a period of time, dust is collected on the surface of the filter material, which reduces the efficiency and resistance of the filter and affects the cleanliness of the air supply. At this time, the filter needs to be replaced in time.
B. Before installing all kinds of filters, it is not allowed to open the packaging; Store the filter according to the direction marked on the packaging box; during the handling process, it should be handled with care to avoid severe vibration and collision.
C.Before the installation of HEPA filter, the package must be unpacked at the installation site for appearance inspection, including: filter media, 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 is in line with the design requirements
D. For the HEPA filter, the installation direction must be correct,after installation, the inner wall must be clean and free of dust, oil, rust and sundries.
E.Before installing the high-efficiency filter, the clean room must be fully cleaned and wiped. If there is dust in the purified air conditioning system, it should be cleaned and wiped again to meet the cleanliness requirements. If a HPEA filter is installed in the technical interlayer or suspended ceiling, the technical layer or suspended ceiling should also be thoroughly cleaned and wiped.
