Reusing N95 Masks

"Thought wearing masks do not protect anyone from catching it."

Then why is it so important for medical caregivers to have masks? It certainly isn't to protect the patient from catching the virus, they already have it. Something doesn't add up about advice to the public regarding masks?

LiveSteamer said:

"Thought wearing masks do not protect anyone from catching it."

Then why is it so important for medical caregivers to have masks? It certainly isn't to protect the patient from catching the virus, they already have it. Something doesn't add up about advice to the public regarding masks?

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Yes, I believe this example would qualify as a reason why people may not trust big brother.

sino26 said:

My wife is an RN. Her hospital has gone from one N95 mask per shift to everyone being told to reuse masks. I don't think they are cleaning them, just storing in a ziplock with their name on it. They are saying WTF though. Housekeeping staff don't get masks so i guess it's better than nothing.

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THAT is STUPID. So the outside of the mask is contaminated. So you put it in the bag, and that contaminates one side of the bag. Next day, you put it in the bag the other way around and contaminate the inside.

This is why that is NOT an acceptable practice.

Xshot said:

How do the respirators with replaceable cartridges compare to the N95 masks? I was under the impression my respirator was infinitely better at filtering everything and anything than the N95 mask. I can't find anything definitive online about it.

My wife is pregnant and if there's an emergency and she needs to leave the house I want to give her whichever is better obviously.

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It depends on which cartridges.

But in general, they are better. Especially since you can fit check them each time you put them on to see that it is sealing.

HEPA filters are the highest normal level of filtering.

P100 is step down.

N95 is the lowest level for this use.

LiveSteamer said:

"Thought wearing masks do not protect anyone from catching it."

Then why is it so important for medical caregivers to have masks? It certainly isn't to protect the patient from catching the virus, they already have it. Something doesn't add up about advice to the public regarding masks?

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N95/P100 masks are to protect the health care workers.

Surgical mask are to the protect the patients.

N95 masks CAN prevent catching it from breathing. But they do not protect you from touching a contaminated surface then touching your face, transmitting the virus.

Xshot said:

I believe if someone coughs/sneezes directly on you it can be transmitted, but mainly it's through touch.

But what do I know.

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It can def be transmitted via sneeze. It also is starting to look like sneezing/cough/air(?) is giving the highest viral load. I've also read that scientists believe that more people are getting infected via sneezing/cough/air(?) than touch. I do not have a source for that though.

But here is a graph which shows viral loads compared to sneeze vs touch.



So they're saying the severity of COVID19 likely depends on the viral load upon initial infection. Which makes sense. Remember the whistleblower doctor in China who was only 34 and died? He probably got huge viral loads and maybe multiple times when working with patients.

Pinecone said:

THAT is STUPID. So the outside of the mask is contaminated. So you put it in the bag, and that contaminates one side of the bag. Next day, you put it in the bag the other way around and contaminate the inside.

This is why that is NOT an acceptable practice.

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This is why we are using the alcohol dip method. Our masks are just the standard double ply type. I just don’t have any other way of protecting ourselves.

For the guys wearing cartridge type respirators we can’t get the tight type of 3m filters but I was able to buy some other type and I’m working on 3D printing an adaptor so we can use the Moldex type filters with the 3m masks. I also cut apart a filter and replaced the media with some standard HEPA HVAC filters that I had t home and cut up to fit inside of the Trapezoid shaped 3M cartridges. Again There are just no good alternatives to nothing.


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ToolAA said:

This is why we are using the alcohol dip method. Our masks are just the standard double ply type. I just don’t have any other way of protecting ourselves.

For the guys wearing cartridge type respirators we can’t get the tight type of 3m filters but I was able to buy some other type and I’m working on 3D printing an adaptor so we can use the Moldex type filters with the 3m masks. I also cut apart a filter and replaced the media with some standard HEPA HVAC filters that I had t home and cut up to fit inside of the Trapezoid shaped 3M cartridges. Again There are just no good alternatives to nothing.

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Nice of you to be the test dummy for those setups. Seriously, it may work, or may not work at all.

So you end up with a false sense of security. And don't get caught by MOSH doing this.

provvv said:

It can def be transmitted via sneeze. It also is starting to look like sneezing/cough/air(?) is giving the highest viral load. I've also read that scientists believe that more people are getting infected via sneezing/cough/air(?) than touch. I do not have a source for that though.

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With all respiratory illnesses, the primary transmission route is inhalation from airborne particles.

High infectious load, delivered right to the susceptible part of the body.

Touch transmission is secondary. But still a viable route.

Official guidance from 3M on disinfecting N95 respirators

https://multimedia.3m.com/mws/media...disposable-respirators-technical-bulletin.pdf

Short answer DO NOT DO IT.

Passing along this link to 3D printed masks if you’re into that

https://www.ar15.com/forums/general...rator-substitutes-UPDATED-FILES-/194-2308138/

Doom and Bloom did a video on reusing masks. Seems that China did studies on it and found that only one way worked to maintain the filtering properties. Still not recommended for normal times. Up to you to decide what normal times are.

https://www.doomandbloom.net/video-can-n95-masks-be-reused/

Pinecone said:

Official guidance from 3M on disinfecting N95 respirators

https://multimedia.3m.com/mws/media...disposable-respirators-technical-bulletin.pdf

Short answer DO NOT DO IT.

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It’s interesting in that the report found that disinfection did not reduce the filtration performance of the mask but caused issues with the fit.

The 3M study found the filtration performance was not affected, in that the respirators continued to provide at least the minimum filtration efficiency required for the N95 designation. However, all three disinfection methods caused damage to at least one respirator in each sample. Observed damage included: delamination or compression of the respirator’s nosefoam, strong burnt odor, the respirator straps on the 1870 lost elasticity, and the MGS and moist heat methods melted the respirator material surrounding the metal noseclip and staples.

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So while 3M rightfully cannot recommend doing it it does seem possible. My method of alcohol dip seems not to cause any adverse effects physically. The mask dries out quite quickly and the straps and seal still fit tight.

Again I would not advocate this method under normal circumstances but I have no other way to protect myself right now.


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I would try using an iron or a clothes streamer to treat the masks. The steam coming off of those things is probably 350-400 degrees and should help kill the virus. However, I’m not too familiar with the materials used to make the N95 mask so I’m not sure if the high temperature steam might compromise the mask.

****I work with people that could potentially have a very short life expectancy if they get the Chinese Wuhan Virus. We have a small supply of N95 masks left. We have perhaps 5 masks per person that are going to have to be re-used until we get more masks, that are on back order... What we have done, and seems to work well without affecting the fit of the masks is use a Clorox disinfectant wipe in a ziplock bag (5 zip lock bags, one for each mask...). We put the mask in the zip lock bag sealed tight with the Clorox wipe overnight, and in the morning take the mask(s) out and let it dry, which does not take long. We have also used denatured alcohol. The mask is ready to use, and we have the techs 5 masks labeled with their name, etc.. in the bag. Five masks are supposed to last for the day, and thankfully we don't have to wear them all the time. We are next door to a lab that does have equipment for testing gram positive and negative bacteria (which is NOT a virus....it's bacteria...). and they did some tests for themselves using material in masks that had been purposely contaminated with bacteria they use in their labs for research and for calibrating equipment. The cold sterilization using a clorox wipe or denatured alcohol in a wipe or paper towel killed the bacteria for the most part to very very low levels when the medium was exposed overnight.

It might be worth a shot if you have no other option, or have nothing left other than used masks... Again, the testing was only done with bacteria, but the Clorox or Denatured alcohol killed most everything in the mask material as long as it was sealed up overnight and let dry in the morning. It did not seem to affect the integrity of the fit of the masks. Dunno about the exhalation valve, etc..

It's a crummy option, and less than ideal, but until we get more new masks, it's the best option we have with at least *some* testing done (again.. on bacteria NOT viruses...) Just make sure the mask is dry before putting it on.

Anyway, for what it's worth.

halic1 said:

I would try using an iron or a clothes streamer to treat the masks. The steam coming off of those things is probably 350-400 degrees and should help kill the virus. However, I’m not too familiar with the materials used to make the N95 mask so I’m not sure if the high temperature steam might compromise the mask.

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The Laws of Physics must cease to exist in your world. Is that "magic steam"?

adit said:

The Laws of Physics must cease to exist in your world. Is that "magic steam"?

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He meant Celsius. Damn metric system.....


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Wife has a friend who is a physician in Brooklyn, NY. She says the hospitals there are overwhelmed, and the docs are using one N95 mask per week. They haven't been able to get resupply.

Alcohol seems to reduce the effectiveness of filtration according to this article... again some protection is better than no protection. It looks like the oven is the safest.

https://m.box.com/shared_item/https...0b7V6OXFJoGblf-0KZ8uXDYqDZG4s_bt90EMWGTj2z3tU

Gcs7th said:

Alcohol seems to reduce the effectiveness of filtration according to this article... again some protection is better than no protection. It looks like the oven is the safest.

https://m.box.com/shared_item/https...0b7V6OXFJoGblf-0KZ8uXDYqDZG4s_bt90EMWGTj2z3tU

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That link seems to be broken. I read in another thread that Alcohol may reduce effectiveness because it changes the static charge of the filter media.

Steam and UV may be the best options at this time. Damn difficult problem to deal with.