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.

With the emergence of some new application scenarios, the detection of filters faced the problem that traditional methods and detection equipment can't meet the new requirements.
After investigating the filter testing rigs (systems) and manufacturers in the domestic and foreign markets, customers finally chose to cooperate with our company. Scince Purge use our own industry experience and professional advantages to provide customers with testing system to meet the testing needs.

Filter industry is a highly specialized industry, but there are few corresponding courses in universities. It can be said that it is an industry that needs practices and experiences. From filter media to filter elements, there are many factors that affect the filtration efficiency of finished filter elements. Material selection and structural design of filter element stage are need testing equipment. The detection of finished filter elements is also essential. No matter how good the filter medium are, it is inevitable that the filter material will be damaged and the bonding will be incomplete in the process of discount and adhesive bonding.

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.

What is MERV？American National Standards Institute (ANSI) and American Society of Heating, Refrigerating and Air-Conditioning Engineers (ASHRAE) standard 52.2, MERV is minimum efficiency reporting value.It is wrong to say that the higher the MERV, the better the filter. MERV is designed to enable users to select appropriate filters according to the size of particles they want to remove. MERV system is to grade filters, not to comment on which filter is better. Is the protection effect good if the MERV grade of the filter is appropriate？The answer is no. Correct installation is also an important means to ensure the filter efficiency.

Air filters are devices that use filtration, adhesion or charge trapping to remove airborne particles, gases contaminants and microorganisms. They can be used everywhere in our lives. They are used in clean rooms for the production of medical masks, electronic products, semiconductors, etc. And those closely related to our lives are filters for air conditioning, filters for purifiers, fresh air units for HVAC systems, primary return air conditioning units and so on. How to grade and select these filters to ensure our health?

In the air, in addition to suspended particulates, there is a category of harmful substances - chemical gases, which are often invisible and untouchable, but more harmful to people, even fatal. They exist in the form of gaseous molecules, which cannot be removed by ordinary filters, but require molecular adsorption, such as activated carbon and molecular sieve porous media.

Air filtration materials such as meltblown fabric and electrostatic cotton are electrically charged by means of water electret and electric electret in order to obtain high efficiency. Materials such as glass fibre and PTFE, and filters made of them, can also become electrically charged for various reasons. These electrostatic charges are not completely reliable and will decay over time and with the environment changes, thus affecting the filtration efficiency of the masks and filters. Therefore, the effect of static electricity on the filtration efficiency of filter materials, masks and filters needs to be examined.

This paper interprets the relevant standards, hoping to help understand the relevant domestic and international regulations.

In order to facilitate you to get the performance test method of vacuum cleaner and cleaning robots (automatic/robotic floor cleaning machines, autonomous robotic vacuum), we summarize the standard number for your reference. IEC/EN 60335-2-69, IEC/EN 60312, ASTM F1977-04, IEC/ASTM 62885-7-2020, IEC 63327:2021