Performance, Protection, and Sterilization of Face Mask Materials

https://utrf.tennessee.edu/information-faqs-performance-protection-sterilization-of-face-mask-materials/

by imagetic • 6 years ago

80 27 6 years ago

utrf.tennessee.edu

a-wu2• 6 years ago

There's been a lot of press about people making their own face masks out of fabric and it got me thinking about copper-impregnated fabric (if you watch enough late-night TV you'll have seen those CopperFit infomercials). Copper itself has antimicrobial properties (studies say SARS-CoV-2 only lives 4 hours on copper), but does anyone know if there is enough copper content in those fabrics to make them a better fabric for face masks than cotton?

foxyv• 6 years ago

I think it's better to just wash them in soap and water when you get home. A good soap will kill the heck out of viruses.

prostheticvamp• 6 years ago

Or spray with bleach

_ea1k• 6 years ago

I think he is asking if it might improve the performance overall, not necessarily about sterilization. There has been some talk of using salt, for example: https://www.businessinsider.com/mask-coated-in-salt-neutrali...

gruez• 6 years ago

Copper itself has antimicrobial properties (studies say SARS-CoV-2 only lives 4 hours on copper), but does anyone know if there is enough copper content in those fabrics to make them a better fabric for face masks than cotton?

I think you answered your own question. Viruses only get killed if they're on copper for 4 hours, so it might be useful if you wanted a self-disinfecting mask, but if the material itself doesn't filter properly the antimicrobial properties of copper doesn't matter because the viruses fly straight through and aren't affected by the copper.

a-wu2• 6 years ago

Right. I should've phrased the question as: is the copper content sufficiently high enough to make a significant impact on the disinfection rate compared to just say, cotton? Obviously it won't make a difference (I think?) during wear, but if it the virus dies quicker than on cotton then one could potentially disinfect the mask less frequently.

mantap• 6 years ago

I personally wouldn't. Fabric sheds, having tiny microparticles of copper lodged in your lungs is probably not advisable.

Abishek_Muthian• 6 years ago

This is very useful, I have made a 3 layer Qualitative Filter based face mask with middle layer soaked in brine solution for possible virus deactivation[1].

With more governments officially recommending DIY face masks for public, so that proper N95 masks can be left to the health care workers; I would love to get my mask scientifically tested.

[1]https://abishekmuthian.com/diy-qualitative-filter-face-mask/

Androider• 6 years ago

The CDC suggests it might be possible to re-use masks after storing them in a paper bag for a while https://www.cdc.gov/niosh/topics/hcwcontrols/recommendedguid...

I also wonder how such re-use of a mask combined with more durable N99 masks that are ordinarily rated at hundreds of hours for the filter (compared to 8 hours for your average N95 mask) could be used as a more permanent mask for households if only used occasionally when going to get groceries for example.

omgJustTest• 6 years ago

"He does not give any advice on the performance of the re-sterilized N95 or mask against the virus."

So... we want the attention but not the risk of you taking our advice. If you have something of interest, why haven't you contacted people whose lives you could save?

dang• 6 years ago

Single-purpose accounts aren't allowed on HN.

imagetic2• 6 years ago

meaning it's not tested against the actual virus. He is a materials scientist, the one who invented the process we use for n95 rated materials.

nominated1• 6 years ago

What if I have X masks and rotate their usage without any cleaning at all. Would this allow the virus to die naturally without the need to clean the mask?

renewiltord• 6 years ago

Yes, this will work and is current healthcare professional practice in many places. It will take a few days, though, so people usually line up like 5-6 and then rotate through those.

If you can heat the masks that's cool, too, but then you have to make sure you don't damage the elastic or seal. Waiting will work.

cryoshon• 6 years ago

according to the OP paper, that's an unproven strategy. i can't find anything else supporting it in the literature linked by that paper either. so the real answer is that we don't know.

however, while it appears to be unproven, given what we know about how long the virus survives on different materials, i would say that it is probable that leaving a mask aside in a dry spot for a week or so is effective at ensuring there are no viable viral particles remaining on the mask.

as long as we're using unproven decontamination methods, i'd say to also leave the external surface of the mask in direct sunshine for a few hours too.

as the OP paper notes, sun bleaching / UVR does degrade the quality of the filtration by a small amount (around 1.5% if i recall) but it's also effective at destroying viral particles in a short period.

oski• 6 years ago

If you know any healthcare workers (doctors or nurses), have them checkout https://www.n95decon.org/ to follow the latest on sterilizing face masks.

N95 masks should be reserved for HCWs as there is a major shortage. Most people should just wear nonmedical fabric or homemade masks, but everyone should wear some kind of mask when out and near other people. See https://shouldiwearafacemask.com

K2h• 6 years ago

Great resource, the last one I was working off of on this topic was from Stanford: https://aim.stanford.edu/covid-19-evidence-service/

-Latest as of 3/29 V1.2 https://stanfordmedicine.box.com/v/covid19-PPE-1-1

motohagiography• 6 years ago

Couple questions for scientists on the thread:

- If it is true that soap kills the virus by breaking up it's outer lipid layer, does that mean soaps and degreasing agents and coatings may also kill it on surfaces like clear visors, gloves and other fabrics?

- While N95 (non oil particulate) masks are considered sufficient, and P and R 95+ (oil particulate filters) are not considered necessary - are those oil particulate filters also considered sufficient?

- can folded, oil-absorbant paper shop cloths provide more protection than cut-up t-shirts and regular cotton?

TylerE• 6 years ago

Yes... P/R95 is a strict sub-set of N95. It's an additional capability.

lootsauce2• 6 years ago

Tech Ingredients did a fantastic video on the subject recently, I love everything from this guy and the recent series in response to COVID-19 is great stuff.

https://www.youtube.com/watch?v=2UdtKssU7po

lootsauce2• 6 years ago

After reading the article there is an important insight I did not know of and clearly neither did Tech Ingredients as they demonstrate use of alcohol.

from the article

"the FE (filtration efficiency) of these masks is influenced by the electrostatic charges embedded within the fibers of the filtration layer(s) in the interior part of the masks."

"... using alcohol will erase the charges. However, exposing the masks to air at elevated temperatures such as 70℃ for 30 minutes allows the charges to be retained."

prpl• 6 years ago

Naively I would guess an easy way to sterilize is in a ziplock bag under water (sous vide) at 70C

imagetic2• 6 years ago

That's a good question!

https://community.anovaculinary.com/t/sous-vide-a-face-mask-...

Performance, Protection, and Sterilization of Face Mask Materials

Related Stories