Questions...
What about the filters when you are cleaning the mask, leave them on or take them off?
For a regular half-face with two cartridges do you have a WAG on how long they can be used and how effective are they when used in this context (CV-19)? They are Honeywell-North NIOSH P100 part number 7580P100.
What is a good household material to use as a pre-filter wrapped and secured over each of the two filters?
Thanks!
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With a standard N95 or N100 filter, you can use them till they are hard to breath through. For a prefilter, well I typically don’t use them as the bayonet filters are disposable. It wouldn’t do much good anyway unless it is N95 or better. I know of hospitals making their own N95 masks using HEPA furnace filters.
https://www.unitypoint.org/filesimages/COVID-19/UnityPointHealth-OlsonMask-Instructions.pdf
Using furnace filters MAY help.
For length of use... Well I once work some pink N95 filters for 90 days with out changing out. They were for crystalline silica, and not a “hot” zone so I would pull the filters before cleaning the mask, inspect the seals, and then reassemble. DO NOT wash with the filters on. Bleach destroys the filter material. In a Cl gas cartridge, you have layers to stop the chlorine, then the particulate.
In a “hot” zone, the outer layer of the filter will be the hottest. I have reused cartridges in known hot zones, but they had to be pulled while wearing PPE, and reattached while wearing the same. If you can, since this is a biologic, let the cartridges sit some place till the bug is assumed dead if you have to reuse. Not sure how long, but assume it is the same length of time as exposed fabric. You can do a quick clean with an alcohol wipe, but I would not use to much.
Again, we typically never tried to reuse the cartridges from a hot zone. Just threw them away as part of the decon process. Looking back, that was a hell of a luxury