PERFORMANCE DATA of Face Masks

Filtration Value – the % of particles of a certain size, filtered out by a mask. This is determined by a mask's filtration material and its pore size in microns. A mask that filters out a higher % of small particles is more protective. It is important to know both the % of particles filtered and the size of the particles. Two terms used to describe these values are Bacterial Filtration Efficiency (BFE) and Particle Filtration Efficiency (PFE).

What is "Particle Filtration Efficiency" (PFE)?
% of particles filtered out (do not pass through) at a pore size of 0.1 – 1 micron.

What is "Bacterial Filtration Efficiency" (BFE)?
BFE measures the filtration efficiency of a mask using viable (live) particles (bacteria) that vary in size from 1 micron to 5 microns.

Which is better - a higher BFE or PFE rating?
Answer -PFE. The micron particle size is no larger than 1.0 micron, thereby providing the wearer with increased protection.

Which is more important- BFE/PFE rating or micron particle size? Both. A mask with a BFE rating of 99 percent at 3.0 microns may provide less protection than a mask with a PFE of 98 percent at 1.0 micron. Do not be misled by a high BFE/PFE rating without knowing the micron particle size upon which both are based.

What is Delta P in relation to masks?
The Differential Pressure (DP) is a test that measures how easily air is passed from one side of the mask to the other. This indicates how easily the wearer can breathe through the mask, and is indicated by Delta P. Higher differential pressure indicates air is more difficult to push through. This could result in a "blow-by" effect (escape of air, and contamination from the sides of an improperly worn mask), or even incorrect use by the wearer.

Fluid Resistance – one of the most important features of a mask. When masks become saturated from both inside and outside, “wicking” or the rapid transfer of substances through the mask is likely to occur. High fluid resistance means better, longer lasting masks.

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