Half Face Respirator P100 "life"


Forum Probie
I have a 3M "half mask" with P100 2091 filters. Everything I read says "6 months or 40 hours of use", however that appears to be for industrial use. Does anyone know how long the filters are good for as respiratory protection against Covid-19? Is there a way to "sanitize" these?


Forum Captain
Use the filter until breathing becomes difficult. You don't sanitize filters, anything you could do to them would likely ruin their ability to actually work. If you need to prevent contamination, then you would need to dispose of the filter and sanitize the mask. They are not reusable, but they do not lose effectiveness as they "fill up", they actually become better filters (which is why they get harder to breath through).

And use 2297's instead, they have activated charcoal to eliminate odors and are easier to breath through... your own personal clean room.

P100 filtration is good down to .3 micron. The virus size goes down to .015 micron, or twice as small. So good for droplet protection but not technically able to filter the actual virus.

The primary infection route as we understand it appears to be hand to face rather than breathing it in. So avoid touching your face and wash or use hand sanitizer before you do.
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Community Leader
X100 masks are TESTED at 0.3 microns as that's the size particle that most easily penetrates them. Same goes for X95 and X99. The reason I use "X" is that there are N, R, and P masks, all of which are tested for their ability to filter 0.3 micron particles to a specified level. The N/R/P designation is for their resistance to oils. An X95 mask is certified to filter 95% of those particles. An X99 mask is certified to filter 99% of those particles. An X100 mask is certified to filter 99.97% of particles. Here's what is not often told to you: many X95 masks will actually filter between 99% and 99.97% of the particles they're tested against, so most could qualify as an X99 or X100 mask but because the batch tested may not entirely filter at that level, the batch can't be certified to that level, so they go to the lower standard instead. The P100 filters you have are considered "oil Proof" (therefore the P rating) and will filter particulates (0.3 microns) 99.97% all the time, thus the "100" designation.

The manufacturer will warrant that performance level for 6 months or 40 hours of use, whichever comes first. After that, you're on your own. Some filters will retain their performance well beyond that. Some won't. Once you go past 40 hours (cumulative) use, you're on your own and you could continue using the filter until breathing becomes difficult (clogged filter) or it becomes physically damaged and therefore physically is unable to filter incoming air.