Reusing N95 Masks

BeoBill · Apr 1, 2020

ToolAA said:
He meant Celsius. Damn metric system.....

Sent from my iPad using Tapatalk

It HAD to be Fahrenheit. 350-400 C would be 630-720 F. Bye bye handle...

ETA:

I came across a chart (possibly elsewhere on MDS) with the amount of time the virus can live on various surfaces. Assuming that the filter medium is some sort of plastic, the virus will die after three days. So rotating 3+ masks or filters with no sterilization will logically allow any trapped viruses to expire on their own, thus self-sterilizing the filter medium.

As usual, this is just applied logic, which may be faulty but is better than nothing or destroying the filter via voodoo sanitization methods.

:fingerscrossed:

Here's the NIOSH Mask Respirator Decontamination link:
https://www.cdc.gov/coronavirus/2019-ncov/hcp/ppe-strategy/decontamination-reuse-respirators.html

I also heard last night that a mask sanitization device company in the midwest was close to FDA approval for their machines. Watch the daily POTUS presser (RSBN is the go to provider) for more info.

Pinecone · Apr 1, 2020

Flametamer said:
Necessity is the mother of invention....

UV-C has been used for years to inactivate pathogens. I have not seen any studies that evaluate UV-C against COVID-19 (its way too soon for that), but it seems reasonable to assume that it can work since it has been proven to work on similar virus'. See the paper referenced on the 'calculations' page at the link below for one such study. (Full disclosure - I am a physicist/engineer who happens to have been a PJ in my prior life; I am neither an MD nor a microbiologist and will not play one here.)

Here is a link to a fire department in Colorado that has done some homework and developed an innovative solution to disinfecting N-95 masks. I've been working on a similar approach for the inside of ambulances (testing yet to be done), but this could be an approach that some folks may find attractive. Their incident flux calculation is very conservative for several technical reasons, but this is not inappropriate for the application (IMHO).

https://www.southforkfirerescue.com/covid-19

Your life, your decisions.

Much of the filtration occurs inside the media. So how to do you get the UV inside the filter fabric.

And as always, you can test and see if your method disinfects, but are you going to test to ensure the respirator meets the N95 testing protocol?

Not good to disinfect the respirator and then have it no longer provide protection.

Tungsten · Apr 1, 2020

I'm amazed copper doesn't kill it faster. 4 hours is about 3 hours and 58 minutes too slow.

Bullfrog · Apr 1, 2020

BeoBill said:
I also heard last night that a mask sanitization device company in the midwest was close to FDA approval for their machines. Watch the daily POTUS presser (RSBN is the go to provider) for more info.

Assuming we're talking about the same company, that is a lttle out of date .. I read an article yesterday that the process had been approved. In fact, it was already approved earlier on a temporary basis, but at a small fraction of the number of masks the company could potentially have processed. State officials raised a stink and the approving agency yielded.

Company is located in Ohio, they are using hydrogen peroxide vapor in the disinfection process. That's all I remember.

onedash · Apr 1, 2020

Seems like a minute or two in heavy ozone would clean a mask. No idea what it would do to effectiveness of mask after repeated detox.

Antarctica · Apr 1, 2020

Didn't pay attention to this thread until I talked to my sister tonight. She's a nurse at a hospital in WV. The hospital is (attempting) to sterilize masks via UV, up to six times per mask (so six days of use). I forwarded her the 3M guidance posted in this thread. I'm sure I ruined her day.

Pinecone · Apr 1, 2020

CDC and 3M have come out with updated guidance.

They both say, DON'T.

BUT, if you have to, the hydrogen peroxide vapor method seems to be the way to go.

welder516 · Apr 4, 2020

Seen a woman on FB taking women's leggings and cutting them for general purpose mask , just thought I would give some members options .

Pinecone · Apr 5, 2020

welder516 said:
Seen a woman on FB taking women's leggings and cutting them for general purpose mask , just thought I would give some members options .

Only thing it does, it to give the wearer a false sense of security.

HSTD · Apr 7, 2020

antifa-be-like-found-this-sweet-mortal-kombat-mask-in-21240523.png

could work...

Pinecone · Apr 23, 2020

OK, some updates on reusing N95s. This is what is coming out from various agencies and based on sound science and testing.

1) The best was to reuse is rotation. Best case, you have 5 N95s for a 5 day work week. On Monday, you wear the first one. At the end of the day, remove it, handle carefully to NOT touch in the face side. Put it in a clean PAPER bag, and label it Monday. Repeat for the next 4 days. Next week, you take the Monday bag, take out the N95 and use it. YOU THROW AWAY THE BAG. At the end of the day, you use a NEW bag to store it for the week.

2) To disinfect, the best way, and seems to not compromise the filter or the fit, is hydrogen peroxide VAPOR treatment. However, this requires specialized equipment to generate hydrogen peroxide vapor.

3) Next best way is warm heat. You can microwave them in one of the bags designed to disinfect nursing (as in feeding babies) equipment. Amazon has the bags for this. The problem is, there is no good guidance yet on how long to microwave. And doing it too long will damage the N95, so it not longer provides the protection.

Realize, that NO DISINFECTION is optimal. Multiple N95s and a rotation system is the best for reusing.

Of course, the BEST is to use it one day/shift and throw it away.

BTW, comparing the efficiency of an N95 and surgical masks and home made face coverings, there was a study that was done by a personal protective equipment company. They did quantitation fit testing, that actually measured the level of contaminants inside the device and outside. They used virus particles, but a harmless one.

An N95 measured a protection factor of about 113. That is, for every 113 particles in the air outside the device, one got in.

A surgical mask measured about 4.8 protection factor. Or, in other words, an N95 is over 23 times as effective in stopping you from breathing in viruses. This is not surprising in that a surgical mask is not designed to protect the person wearing it, but to protect the patient from the health care persons. They can work, but only if EVERYONE is wearing one or something better, as they are very good and preventing the person wearing it from infecting others.

A home made face covering (using one of the common online designs) was measured at a protection factor at between 2 and 3. So half the effectiveness of a surgical mask, and an N95 is more than 46 times as effective.

ToolAA · Apr 23, 2020

Pinecone said:
OK, some updates on reusing N95s. This is what is coming out from various agencies and based on sound science and testing.

1) The best was to reuse is rotation. Best case, you have 5 N95s for a 5 day work week. On Monday, you wear the first one. At the end of the day, remove it, handle carefully to NOT touch in the face side. Put it in a clean PAPER bag, and label it Monday. Repeat for the next 4 days. Next week, you take the Monday bag, take out the N95 and use it. YOU THROW AWAY THE BAG. At the end of the day, you use a NEW bag to store it for the week.

2) To disinfect, the best way, and seems to not compromise the filter or the fit, is hydrogen peroxide VAPOR treatment. However, this requires specialized equipment to generate hydrogen peroxide vapor.

3) Next best way is warm heat. You can microwave them in one of the bags designed to disinfect nursing (as in feeding babies) equipment. Amazon has the bags for this. The problem is, there is no good guidance yet on how long to microwave. And doing it too long will damage the N95, so it not longer provides the protection.

Realize, that NO DISINFECTION is optimal. Multiple N95s and a rotation system is the best for reusing.

Of course, the BEST is to use it one day/shift and throw it away.

BTW, comparing the efficiency of an N95 and surgical masks and home made face coverings, there was a study that was done by a personal protective equipment company. They did quantitation fit testing, that actually measured the level of contaminants inside the device and outside. They used virus particles, but a harmless one.

An N95 measured a protection factor of about 113. That is, for every 113 particles in the air outside the device, one got in.

A surgical mask measured about 4.8 protection factor. Or, in other words, an N95 is over 23 times as effective in stopping you from breathing in viruses. This is not surprising in that a surgical mask is not designed to protect the person wearing it, but to protect the patient from the health care persons. They can work, but only if EVERYONE is wearing one or something better, as they are very good and preventing the person wearing it from infecting others.

A home made face covering (using one of the common online designs) was measured at a protection factor at between 2 and 3. So half the effectiveness of a surgical mask, and an N95 is more than 46 times as effective.

Thanks for the report.

Shogunade · Apr 23, 2020

ToolAA said:
Thanks for the report.

Seriously. Great info. Thanks.

Alan3413 · Apr 23, 2020

Any indication how effective are PM 2.5 masks? They are sold as pollution masks on Amazon and come with replaceable filters supposedly good for a week.

Alan3413 · Apr 23, 2020

Found more info on filtering efficiency and mask type

https://smartairfilters.com/en/blog/coronavirus-pollution-masks-n95-surgical-mask/

https://smartairfilters.com/en/blog/do-pollution-masks-work/

Pinecone · Apr 24, 2020

Alan3413 said:
Any indication how effective are PM 2.5 masks? They are sold as pollution masks on Amazon and come with replaceable filters supposedly good for a week.

The problem is, PM2.5 masks are rated against 2.5 micron particles.

N95, P100, and HEPA are rated against 0.3 micron particles.

So a PM2.5 will help some, but it is not as effective as an N95.

Pinecone · Apr 24, 2020

Alan3413 said:
Found more info on filtering efficiency and mask type

https://smartairfilters.com/en/blog/coronavirus-pollution-masks-n95-surgical-mask/

https://smartairfilters.com/en/blog/do-pollution-masks-work/

The problem with the home made and surgical masks is not the ability of the material to capture the particles, but the FIT of it against the face. Without a proper tight fit, when you inhale, the air comes in the gaps versus coming through the filter material. And that air is unfiltered. Path of least resistance, the path through the gap has less resistance to the airflow than through the filter.

The test you linked to only looked at the performance of the actual filter material.

The study I quoted tested them devices on the person's face, while they breath. And compared the particle count inside and outside the device.

Another issue is their testing method. The analogy (which is not fully accurate, but illustrates the issue), is you cannot push a rope. You may get different results between pulling the air through the filter at normal breathing pressures, versus pushing them through with the engine exhaust pressure.

welder516 · Aug 21, 2020

For anyone still trying to obtain N95 mask . Keen Gases on Rt. 40 in Rosedale (Hooker Hwy.) has a approx. a dozen boxes at 22.00 for a box of 10 . Now i am not vouching for pricing but i picked up 2 boxes to supplement our stock .

I figured i would let some members know if there is a need . 3M # 8511 Made in the USA . I am sure they will sell to the general public but the cost might be slightly higher if you don't have an account (Not Sure) please call and ask .

Reusing N95 Masks

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