Many customers will ask about the difference between BFE and PFE for the introduction of mask instruments by GBPI. Today, GBPI takes everyone to understand the difference between them.
The filter material of the mask is basically a melt-blown non-woven fabric of polypropylene material. The pore size and thickness of the fiber affect the filtering effect. Particles of different diameters are filtered by different principles, such as particle volume, impact, and diffusion principles, which are blocked by fibers, and some particles are filtered by electrostatic fibers through electrostatic attraction principles.
The filtration efficiency test is carried out under the particle size specified in the standard. Different standards will use different sizes of particles for testing. BFE often uses bacterial aerosol particles with an average particle diameter of 3 μm, while PFE generally uses sodium chloride particles with a diameter of 0.075 μm. From the perspective of filtering effect alone, the effect of PFE is higher than that of BFE.
In the standard test of the commonly heard KN95 grade masks, particles with an aerodynamic diameter of 0.3 μm are used as the test object, because particles larger or smaller than this diameter are more easily intercepted by filter fibers, and particles of intermediate size such as 0.3 μm It is more difficult to be filtered. Although the virus is very small, it cannot be transmitted in the air alone. It needs droplets and droplet nuclei as a carrier to float in the air, so it is easy to be filtered out.
Particle filtration efficiency PFE (Particulate Filtration Efficiency): the filtration effect of micro particles, the larger the value, the better the filtration effect.
Bacterial Filtration Efficiency (BFE): The filtration effect of bacteria, the larger the value, the better the filtration effect.
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