Are these respirators spewing covid viruses?

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This is an ER doctor in New York with a respirator with cartridges.

Due to shortages of the N95. There are hundreds of doctors in my country using them too. I even bought one. But I noticed something dangerous. The exhalation valve has only a thin rubber flap that moves when you talk or exhale (see pictures below). If the person wearing it is COVID-19 positive, can he/she spread the virus in the ER to the patients without covid?

I actually discussed this with a brain surgeon who was also using it. Then she realized only a thin flap stands the way between the wearer and outside, and there is not even any filter. There are hundreds of others who may not be aware of this.

I'd like to confirm it with people familiar with this. Can the exhalation valve of this indeed let out viruses from the wearer? If it really can. I will warn the hundreds of doctors and frontliners using it in my country. They may be releasing more viruses into other patients.

This is the breakdown of the units:

3m 7502 main.jpg



3m 7502 disassemble.jpg


3m 7502 flap removed.jpg


exhalation valve.jpg


The small thin rubber flap at center above moves out when you speak or exhale inside the respirator. What if the wearer is covid positive and exhale or cough out? Can the virus be released directly into the lying patient below the doctor or frontliners (like below actual) wearing it?

frontliner using respirators.jpg
 
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  • #2
BillTre
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The short answer is probably yes.

Since there is no filter on the out-going air the only entrapment of exhaled virus would be if virus particles stuck to the inside of the mask and other exposed surfaces.
This is similar to the situation in a previous post somewhere around here where filtered air was being pumped into a face mask or helmet of some kind. Its great for protecting the wearer but does not prevent spread from them to others.
Therefore it would seem to only be appropriate for confirmed non-infected people (if that exists).
 
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  • #3
phinds
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Therefore it would seem to only be appropriate for confirmed non-infected people (if that exists).
I disagree completely. Yes, the mask can allow exhalation of contaminated particles but what it does NOT allow is the "spewing" of those into a wide area the way you get if someone is breathing or talking out into the open air in front of them.

Cloth masks are also useless for preventing the exhalation of contaminated gas but they also block "spewing". That's why these masks are both good for contaminated people to wear and that's why cloth masks are now being widely recommended. For cloth masks in particular it's far more useful for contaminated people to wear them than for uncontaminated people to wear them.
 
  • #4
BillTre
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I disagree completely. Yes, the mask can allow exhalation of contaminated particles but what it does NOT allow is the "spewing" of those into a wide area the way you get if someone is breathing or talking out into the open air in front of them.
Seems like there would be a faster airflow out of the vent since the same volume of air funneled through the small opening would have to travel faster than that it would be going through the "open air in front of them". This could, depending on the details, push contaminants out further.
As I said above, the only way the virus would be removed (equivalent to filtered) would be if it were to stick to the inside of the mask, valve, etc..
 
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  • #5
phinds
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Seems like there would be a faster airflow out of the vent since the same volume of air funneled through the small opening would have to travel faster than that it would be going through the "open air in front of them". This could, depending on the details, push contaminants out further.
The exhalation vent on these types of masks point down, not out.
As I said above, the only way the virus would be removed (equivalent to filtered) would be if it were to stick to the inside of the mask, valve, etc..
Since we agree on that it seems pointless to belabor it.
 
  • #6
BillTre
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The exhalation vent on these types of masks point down, not out.
OK, but they could still contaminate a local area.
 
  • #7
phinds
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OK, but they could still contaminate a local area.
Absolutely. I have a mask somewhat similar to the design shown and it is a "P100" which means that it is considerably better than the "N95" masks that doctors and nurses use when treating known contagious patients, BUT ... my mask not only has unfiltered ehxalation, even worse it drops beads of condensed breath. Most of the condensation accumulates in the mask and I just wipe it out with a paper towel when I'm done, but sometimes drops come out the bottom. For me this is a major annoyance since it gets drops of moisture on the wood I'm working on but if I were a doc hovering over a patient I was treating, I could inadvertently drop what I think amounts to bodily fluid directly on his/her face.
 
  • #8
BillTre
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Guess I don't undestand why you are arguing about this then.
 
  • #9
phinds
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Guess I don't undestand why you are arguing about this then.
Because my point is those masks are more for the infected to prevent them infecting others that for the uninfected to not get infected. This is exactly the opposite of what your original statement was:
Therefore it would seem to only be appropriate for confirmed non-infected people (if that exists).
 
  • #10
BillTre
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That is in reference to who is wearing the mask and how appropriate it is.
It works to protect the wearer, but would only be good for others if the wearer is not infected.
 
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I am slightly mystified by this entire discussion. A surgeon wears a mask to keep from contaminating the surgical field. These ER docs wear masks to keep from becoming contaminated themselves.
In each case that is the greater good and the appropriate mask.
 
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  • #12
phinds
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That is in reference to who is wearing the mask and how appropriate it is.
It works to protect the wearer, but would only be good for others if the wearer is not infected.
We still take exact opposite points of view about this, and my point of view is the one of the medical experts. Just to be sure we're not arguing about definitions, here's how I perceive it:

Paul: masks useful to protect the wearer from infection but are also for the protection of the uninfected from the infected who are wearing the mask, so EVERYBODY should wear them.

Bill: masks are only useful if UNinfected people wear them.
 
  • #13
phinds
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I am slightly mystified by this entire discussion. A surgeon wears a mask to keep from contaminating the surgical field. These ER docs wear masks to keep from becoming contaminated themselves.
In each case that is the greater good and the appropriate mask.
You are leaving out the general public where the primary purpose of masks is to protect the uninfected from the infected, which has been my whole point in this thread.
 
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  • #14
BillTre
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Paul: masks useful to protect the wearer from infection but are also for the protection of the uninfected from the infected who are wearing the mask, so EVERYBODY should wear them.
This would be ideal, but it only works with masks that filter both inflow and outflow.

The only way an unfiltered outflow mask would meet those goals if it was used by someone who was known to be uninfected, which I don't know if that is really done, thus:
confirmed non-infected people (if that exists)
If people are using those masks, which seems to be the case, then they would only be suitible in the above sense if the wearer was a confirmed uninfected person.
 
  • #15
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Your original picture showed an ER doc with a one way valve mask. My point was that his primary objective is different from that of the the general public for whom a surgeons mask makes perhaps more sense.
 
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  • #16
phinds
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This would be ideal, but it only works with masks that filter both inflow and outflow.

The only way an unfiltered outflow mask would meet those goals if it was used by someone who was known to be uninfected, which I don't know if that is really done, thus:


If people are using those masks, which seems to be the case, then they would only be suitible in the above sense if the wearer was a confirmed uninfected person.
So, your preference would be that the general public not bother wearing masks because they are not perfect and are therefore useless, it seems. We're never going to agree on that.
 
  • #17
BillTre
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So, your preference would be that the general public not bother wearing masks because they are not perfect and are therefore useless, it seems.
Well, this is a completely unfounded and unsupported conclusion, not based on what I was saying.

I think we are basically in agreement, however you seem to be focused on misinterpreting what I say (o_O), so I will be dropping this.
 
  • #18
phinds
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Well, this is a completely unfounded and unsupported conclusion, not based on what I was saying.

I think we are basically in agreement, however you seem to be focused on misinterpreting what I say (o_O), so I will be dropping this.
Well, you are correct that I did not believe that was your intent, so I should not have phrased it so harshly.

@BillTre I have a horrible habit of getting snippy when I'm frustrated. I apologize.

I'm still not convinced that we completely agree but my side of the discussion could have been more constructive.
 
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  • #19
chemisttree
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The N95 masks worn by healthcare workers. Many have unfiltered, valved exhaust. Very bad if the nurse is an asymptomatic carrier.
2FF5B63A-CC77-48C8-AE46-704D2F4064BA.jpeg
 
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  • #20
phinds
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The N95 masks worn by healthcare workers. Many have unfiltered, valved exhaust. Very bad if the nurse is an asymptomatic carrier.
View attachment 261277
Not only that, the exhaust hole points outward. At least the masks in discussion when this thread started have a downward pointed exhaust hole.
 
  • #21
chemisttree
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Yep! Still wouldn’t want to be in the same viral cloud as an infected nurse with one of these.
 
  • #22
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The nurse wears the mask to protect himself. He is not attending church, he is dealing with a sick person!!!1! This is not complicated.............
 
  • #23
chemisttree
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Exactly! Would you remove your N95 in the presence of an infected asymptomatic coworker wearing one of these? Bet you wouldn’t think twice! Cough! Cough!
 
  • #24
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No. Your ER coworker is also festooned with potential contamination, so I don't do not know what the big deal is. No you would not.
 
  • #25
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So these masks with direct exhalation valve direct in front are dangerous because it can spew out contaminated breath? There are no less than 70 frontliners in ER using these in our hospitals. They don't know the dynamics of breath flow.

3m 6200.jpg


face shield enclosed.JPG


Before I warn our government about this. I need to know what happens in ordinary surgical masks used by millions of our populations in lining up at groceries or markets 1 meter apart.

ear-loop-elastic-disposable-surgical-mask-500x500.jpg



When one coughs in surgical masks. So the spew is trap in the masks. But what about the sides. How many percentages of particles can escape from the sides and what are their velocity and distance?

How about an N95. When one coughs inside N95. Where would the particles escape compared to the surgical masks?
 

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