For medical face masks, we often see these characters such as PFE, BFE and VFE. What is the meaning of these indicators? There is a certain correlation between PFE and BFE. For medical face masks, with NaCl aerosol, flow rate 30L/min, when the PFE is higher than 90.0%, the BFE can be higher than 99.0%. Compared with VFE, PFE, when the PFE reach 91.83%, the VFE can reach more than 98%, even higher than 99%. Test aerosol of BFE and VFE are bacteria and bacteriophage respectively, and biological experiment is a very troublesome and complicated process. For mask manufacturers, these indicators are too complex as routine tests. Therefore, some indirect experiences are often used in practice.

ISO 29463 originates from EN1822, which defines EPA, HEPA and ULPA filters commonly used in industry. While ISO 29463 maintains the classification of EPA, HEPA and ULPA.But replace E10-E12, H13-H14 and U15-U17 with the following 13 filter levels. The ISO 29463 can't replace EN 1822, EN 1822 will continue to be valid.

A clean workshop producing color displays has not been built for long. The air supply volume of the air conditioner has become smaller, and the temperature and humidity are out of control. The temperature is far higher than the set value of 22 ± 1 ℃, reaching 30 ℃, and increases with the increase of

Pre-filters, fine filters and HEPA filters are also filters. What are the differences?

Particulate matter and gas are two kinds of pollutants in the air. Particulate matter can be filtered out by using separate air filter media, such as melt-blown non-woven fabric, glass fiber, PTFE, etc. However, chemical gases need to be filtered by using substances with strong adsorption capacity. At present, commonly used adsorption materials mainly include activated carbon, activated alumina, zeolite, molecular sieve, ionic resin, etc.