In Pursuit of PPE

Re:In Pursuit of PPE by rckoepke on Saturday April 18, 2020 @06:19AM (#22906680)

The elastomeric masks allow any filter to be used in them. I have N95 pads in mine. Once a week I swap in "OV" (Organic Vapor) cartridges before I go change the cat litter, the activated carbon in the OV cartridges filter out harmful gases like H2S or even Chlorine gas.

Part of the point, is that the flat, simple, small, replaceable pads for the elastomeric masks use less "melt-blown fabric" than the curved, complex, large N95 face masks. Right now lack of the melt-blown-fabric is preventing us from making enough masks. So being able to make more masks from the same fabric would help a lot.

Most doctors felt the elastomeric masks were inappropriate for healthcare workers. Articles like this are important for helping to challenge that perception. https://elemental.medium.com/a-tiny-hospital-in-texas-might-...

However, the filters do need to be swapped out from time to time. I don't think there's clear guidance on that yet, but there needs to be science backing up any kind of replacement cycle. Once per year would be atrocious, I feel. And of course the rubber itself should be constantly/consistently disinfected as you move between environments or take it off/put it back on.

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Re:In Pursuit of PPE by pmorici on Saturday April 18, 2020 @04:13PM (#22910718)

Industry has been using these masks for years. The masks and filters come with documentation from the manufacture on filter replacement intervals depending on the use case and exact filter medium.

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Re:In Pursuit of PPE by rckoepke on Saturday April 18, 2020 @08:04PM (#22912206)

I do largely agree with this, but this is slightly outside of the typical use case for these masks. I'm not an industrial hygienist or other true PPE specialist, but I am a chemical engineer who has decent experience with a wide variety of PPE and it's been difficult for me to determine when I should replace my 6006 cartridges or 5P716 filter pads for home use (cleaning cat litter, preventing coronavirus).

Here they say to replace when "It becomes difficult to breathe comfortably (this will vary from individual to individual)." https://multimedia.3m.com/mws/media/565214O/3m-cartridge-fil...

This other brochure essentially implies the OV cartridges last up to 6 months, but those don't filter particulates. It does say however, that N95 masks become more effective as they get "dirtier", at the expense of being able to breathe easily. In this case, a tight seal would be extremely paramount, because eventually it would clog enough that you'd be breathing "around" the mask instead of through it. http://multimedia.3m.com/mws/media/447121O/filter-change-out...

They do have a web tool for calculating service life but it assumes you have at least one chemical contaminant, so the tool simply fails to calculate anything at all for hospital or home use.

The "documentation that come with the masks and filters from the manufacturer" are of no help to me: N95 pads - https://multimedia.3m.com/mws/media/528213O/userinstruction-... https://multimedia.3m.com/mws/media/994802O/userinstruction-...

These are verbatim PDF's of the documentation in the boxes that I have.

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Re:In Pursuit of PPE by pmorici on Sunday April 19, 2020 @02:36PM (#22917821)

The filters meant for chemical contaminants usually have some kind of active absorber ingredient that get used up which is why the replacement intervals are more defined. With particulate (which includes viruses) the only thing you have to worry about is the filter getting clogged or the filter breaking down due to old age but that isn't going to happen with indoor use unless you are talking years. That's why the filter replacement guidelines seems less specific.

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