Please see Adjusters on how to improve designs collaboratively. And become an Appropedia editor to help with these pages. Thanks. -- User:LucasG
This page needs content from the Spanish version and lots of work.
Please see experts:
- twitter.com/jljcolorado
- Aireamos
- Sri et al [[patientknowhow.com]] bring in knowledge, not brands
- Fixthemask
- Etc
Cloth masks. Machine to make them, see somosrim.
Surgical masks.
Respirators N95, FFP2, etc.
Elastomerics.
Requirements.
...
Introduction[edit | edit source]
This page needs work: more links, better text, and maybe improvements to the structure. That said, it is hoped that it is already useful as it is. Please consider linking to this page to attract users, particularly contributors. Also, maybe look at the Spanish version: Proteccion respiratoria personal. Thanks, User:LucasG
Please go to Severe respiratory pandemics for a background understanding of a pandemic, a respiratory pandemic, and a severe respiratory pandemic and also for a framework for the tools needed to prevent, manage, or even terminate one if possible.
Clasification of PPE[edit | edit source]
Masks, face shields, helmets/hoods, excavator
Science[edit | edit source]
- Maths of massive use: what changes when many people use specific filtering-level masks?
- Fitting: air goes out through gaps. Three rubber bands for a better fit (video).
- Filter: N95 masks and how they work (video).
- In and out: when we breathe in, we move so many liters of air into our lungs through the mask's filter. So that filter has "things" (viral particles and other things). Those things go out when we breathe out. So we may "charge" our mask in room 1 and "empty" it in room 2.
Specifications[edit | edit source]
"Better" masks (or other face protection like shields) should achieve these parameters, all of which are achievable but not yet achieved:
- adequate protection: fit (sides) and filtration (front). For the user and others.
- Comfortable/wearable: It is away from the mouth and nose, not heavy, and easy to use.
- reusable: how often, how to clean them, how do we know they still work
- scalable: production in massive numbers, adapting other industries or relying on homemade masks.
- style: people want to wear it.
Designs[edit | edit source]
- improving fit: 3 rubber bands
- improving filtration: different materials
- crazy ideas: could we improve electricity with small (rechargeable) batteries?
Materials[edit | edit source]
- kinds
- combinations
- qualities: washable, breathable, light, availability
Testing[edit | edit source]
- testing for fit
- How to test filtration capacity with home tests
- How to test filtration capacity with industrial tests
- correlation (or lack of) between tests
- cheap and reproducible testing procedures
- https://www.washingtonpost.com/opinions/2021/01/26/n95-masks-safest-next-best-options/
- https://www.statnews.com/2020/04/16/n95-masks-training-needed-protect-against-covid-19/
https://twitter.com/enn_nafnlaus/status/1475267189477457921?s=20
Thread: Mask Fit Testing
This evening, I put all my masks to a proper qualitative fit test using a nebulizer, Bittrex solution, and an improvised hood. From the upper left, counterclockwise:
- HygoStar MP9017 surgical mask
- Demetech DT-N95-FH N95 mask (Amazon)
- Wisent BAU 4837 FFP2 mask (hardware store)
- 3M Aura 9330+ FFP3 mask (Amazon; used for ~20h)
- 3M Aura 9320+ FFP2 mask (Amazon; new)
- 3M Aura 9330+ FFP3 mask (Amazon; new)
- GVS Elipse SPR 644 P100 unvalved elastomeric respirator (Amazon)
- 3M 6800 elastomeric full face respirator (valved) with 3M 2135 P3 R particle filters.
Test setup:
A cheap portable nebulizer was purchased on Amazon:
While you can test with stevia or saccharin, bitrex is generally considered the easiest...
To detect this, so I also purchased a bottle of Ft-30 Bittrex solution:
(Bitrex (denatonium) is the most bitter compound known and is not hazardous to health)
While you can fit the test without a hood just by nebulizing near the mask, a hood can increase the...
... concentration and make detection of aerosols easier. This need not be complex—I used a loose transparent garbage bag, placed it over my torso, and left it open enough at the waste to not pose a suffocation risk.
Masks were tested individually, each going through initial...
I underwent basic breathing tests, speaking tests, tests with angling the head in each direction, and deep/rapid breathing tests. The airstream was directed across my tongue to aid in tasting. At the conclusion of each test, I removed the mask while still in the hood to make sure that I...
I could taste the aerosols easily. Between tests, I ate a small banana to cleanse my palate and avoid getting used to the Bittrex.
Results:
1) Surgical mask: You already know how this is going to go. I actually tasted the Bittrex before I even started the nebulizer.
It was just from putting on the hood that had been used in the last attempt. It was barely better than no mask. Rating: 1/10.
2) Demetech: the masks feel like they have a reasonable fit - certainly better than the Wisent cup mask - though the material feels light. But the bitrex taste came..
... disappointingly quickly, with no difficulty tasting at all. Rating: 3/10.
3) Wisent: This hardware store FFP2 mask is clearly intended for industrial rather than medical uses. Its fit felt poor, and expectations weren't high, but it still outperformed the Demetech. Rating: 4/10.
4) 3M Aura 9330+ FFP3, used: The Aura series is the gold standard in disposable medical FFP2/FFP3 masks, although there are some doubts about whether the ones you find on Amazon are legit. I had used this mask for maybe 20 hours. I was quickly disappointed—while better...
Then, the masks above, I was still very clearly getting Bittrex through it. Rating: 5/10.
5) 3M Aura 9320+ FFP2, new and...
6) 3M Aura 9330+ FFP3, new: I grouped these because I couldn't tell their differences. New, they performed much better...
... then the used Aura. I could still taste a bit of Bittrex through them at high concentrations in regular positions and a moderate amount of Bitrex when looking forward while directing Bittrex around the nosepiece. Rating: 8/10.
7) GVS Elipse SPR 644: What can I say? It aced the test. I might have imagined tasting Bittrex, but I think it was just my imagination. That said, it's certainly not the most comfortable of masks, though you do get used to it - and under prolonged wearing, I find I sweat in it,
... and then who knows how well the seal works. Rating: 10/10
8) 3M 6800: I'd put this in the same "may have imagined tasting something, but probably didn't" category as the GVS Elipse. This is an IMHO much more comfortable mask, but it is vented. Rating: 10/10.
Yet to test: I have an on-order 3M half-facepiece with an official vent filter attachment for source control; I will try it when it arrives, but I expect it to also ace the test.
These are qualitative tests and are not as good as quantitative ones (particle count measurements),...
... but we are still good enough to make some points quite clear:
1) Don't trust "N95" / "FFP2" / "KN94" masks without testing them.
2) A new FFP2 is better than a used FFP3.
3) Elastomeric rock.
Making[edit | edit source]
how to make them: links, keywords
Usage[edit | edit source]
Education for proper use: don, duff, clean situations in which they are most useful, strategies for facilitation (ads rules, teaching, games)
External links[edit | edit source]
- https://www.cell.com/med/pdf/S2666-6340(20)30072-6 recent commentary by @linseymarr and @MonicaGandhi9 in which a few different configurations of tight-fitting cloth masks can work to enhance the fit of a surgical mask (electro-statically charged filter) to get net higher filtration.
- https://hbr.org/amp/2020/10/essential-workers-need-better-masks
- https://christinajwilliamson.com/2020/09/25/cloth-masks-to-reduce-covid19-transmission/
- https://www.fastcompany.com/90542976/this-reusable-mask-is-designed-to-fix-the-28-major-problems-with-the-n95
- 28 problems with masks, pdf linked in the above article
- octosafety.com
- fixthemask.com plus videos
- Article 13 Aug 2020: http://built-envi.com/what-kind-of-mask-should-i-be-wearing-to-protect-against-covid-19/
- Science
- masks4all
- examples:
