Author Topic: Face Masks - a Public Service Broadcast  (Read 761 times)

Offline Allen Smithee

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Face Masks - a Public Service Broadcast
« on: April 04, 2020, 02:07:39 PM »
As this may soon move to a phase where people will either want or be directed to use face masks outside the home (face masks provide a degree of protection for everyone else, not the wearer) I thought a short public information piece might be helpful. I say this because I saw several people today who were wearing them, but doing so incorrectly!

Firstly the masks themselves - the ones that are of any value are certified to either the US N95 specification or the European/British (DIN or BS) EN149:2001 specification - if it's the EN149 styandard it should be one of the two higher grades FFP2 or FFP3. FFP1 masks are not much use in this context. The standard reference should be printed on the mask itself, and needless to say you should only get them from known sources - there's a lot of fake, useless rubbish being offered on odd websites (even amazon) so this is not a suitable time for bargain-hunting!

Masks to the two standards look pretty similar - something like this:



Note the soft aluminium strip bonded to the upper edge. To use the mask this strip should be pressed against the face over the nose so that it forms a close fit, so it would look something like this:



If this is not done then there is a huge leakage when you exhale that steams up your glasses (if you wear them) and negates the whole point of wearing a mask(!). Apologies if this is stating the obvious, but this morning I counted over a dozen people wearing them with the strip still as it came out of the box, so it seams it's not obvious to everyone.

Finally - there is a version of these masks which meets the same standard, but is intended for paint sprayers (and similar) where the main function is to filter incoming rather than outgoing air. These masks have plastic "exhaust valves"  which open up when you exhale for improved comfort. That type of mask is completely useless for this application, so it should be avoided.

<end of public information broadcast>

AS
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Offline nj111

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Re: Face Masks - a Public Service Broadcast
« Reply #1 on: April 04, 2020, 03:53:45 PM »
Good summary! It would have been easy not to think this through and to overlook the exhale valve which most of my 3M workshop masks have!
Nick

Online Vixen

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Re: Face Masks - a Public Service Broadcast
« Reply #2 on: April 04, 2020, 03:55:34 PM »
Can we disable the exhale valve with a stip of tape? Would that work?

Mike
« Last Edit: April 04, 2020, 04:03:14 PM by Vixen »
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Online steamer

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Re: Face Masks - a Public Service Broadcast
« Reply #3 on: April 04, 2020, 04:58:17 PM »
Can we disable the exhale valve with a stip of tape? Would that work?

Mike

Mike if that's what you have, tape it off and use it.....

Dave
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Offline crueby

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Re: Face Masks - a Public Service Broadcast
« Reply #4 on: April 04, 2020, 05:38:54 PM »
Can we disable the exhale valve with a stip of tape? Would that work?

Mike

Mike if that's what you have, tape it off and use it.....

Dave
As long as its not the type of respirator I have for paint fumes, which has one-way valves on input canisters AND the output. Plugging the exhaust on that type would not work!

Offline tangler

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Re: Face Masks - a Public Service Broadcast
« Reply #5 on: April 04, 2020, 07:18:03 PM »
I reckon the main reason for asking the general public to wear masks is to try and prevent the ejection of droplets rather than vapours.  Any of the masks mentioned above will surely do that adequately.

Stay well,

Rod

Offline zeeprogrammer

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Re: Face Masks - a Public Service Broadcast
« Reply #6 on: April 04, 2020, 09:07:35 PM »
Wife made some cloth masks.
We also have the N95 masks but with the valve.
Our intent, should we have to go out in public, is to wear the cloth mask over the N95.
May be overdoing it but hoping that takes care of the valve issue.

BTW Thanks for this thread.
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Offline Mcgyver

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Re: Face Masks - a Public Service Broadcast
« Reply #7 on: April 04, 2020, 10:37:48 PM »
(face masks provide a degree of protection for everyone else, not the wearer)

Do we know that?  Real question, I don't know the answer...but medical types consider it PPE.

Those driving the bus here have such a lack of credibility I don't know what to believe anymore, but its seems entirely plausible the "doesn't protect the wearer" things was to manage the situation, i.e. stop the muggles from buying masks when medical personnel needed them.

I also wonder why we can't be reusing masks....i.e. the virus isn't suppose to survive more than a few days on a surface and can't survive over 125C.  put the masks in the oven and reuse?



« Last Edit: April 04, 2020, 10:43:20 PM by Mcgyver »

Online steamer

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Re: Face Masks - a Public Service Broadcast
« Reply #8 on: April 05, 2020, 01:47:41 AM »
US Surgeon General on making a face mask in 45 seconds....

https://mashable.com/video/cdc-face-mask-how-to/

Dave
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Offline Allen Smithee

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Re: Face Masks - a Public Service Broadcast
« Reply #9 on: April 05, 2020, 10:12:34 AM »
Do we know that?  Real question, I don't know the answer...but medical types consider it PPE.

Because they are in a very different environment which presents a different set of hazards. Nurses and doctors are necessarily in enclosed spaces and close proximity to people who are definitely tested positive, so the air they wade through will contain much more aerosol'd droplets containing Covid19. So they do benefit. They also have masks to the higher FFP3 spec.

The rest of us are in open spaces with ventilation and social distancing, so the primary function of the mask is to reduce the amount of virus-containing droplets we exhale that then settle on surfaces. So we wear them to protect others, rather than ourselves.

AS
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Offline zeeprogrammer

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Re: Face Masks - a Public Service Broadcast
« Reply #10 on: April 07, 2020, 10:37:57 PM »
I'm not sure if this has been discussed....

It's been suggested that we begin wearing masks when we go out (out of necessity for supplies) and I know my parents (who are in a retirement home) are now required to wear masks if they leave their apartment...

A lot of people are making masks out of cloth and the question of sterilization has come up.
I've seen one suggestion to microwave for 2 minutes or so. I think that's a bit dangerous if made with any metal. I don't know if they should be wetted before microwaving.
Another approach is to boil and let dry. Some people question how that affect elastic or other parts but I'm thinking better safe than sorry.
But I don't think boiling is good for purchased masks that may be of a material that will disintegrate.

The idea is to sterilize after every outing.
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Online Vixen

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Re: Face Masks - a Public Service Broadcast
« Reply #11 on: April 07, 2020, 10:51:40 PM »
Zee,

As I understand it.  Microwave radiation alone, won't kill the virus but elevated temperature will. The virus cannot survive temperatures above 155*F (68*C) so steaming, or boiling will work. A microwave cooker will not evenly heat (boil) dampened cloth, so there is a risk of infectious stuff remaining and of course a metal nazal bridges or clips are a fire danger.

Stay strong

Mike
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Online Hugh Currin

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Re: Face Masks - a Public Service Broadcast
« Reply #12 on: April 08, 2020, 01:27:57 AM »
Zee:

I think I'd opt for running them through the wash. Probably not "sterile" but I think they'd be OK.

Thanks.

Hugh

The idea is to sterilize after every outing.
Hugh

Offline Flyboy Jim

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Re: Face Masks - a Public Service Broadcast
« Reply #13 on: April 08, 2020, 02:36:19 AM »
Zee:

I think I'd opt for running them through the wash. Probably not "sterile" but I think they'd be OK.

Thanks.

Hugh

The idea is to sterilize after every outing.

That's what they talked about on the news tonight. After every use.......wash in hot water.

Jim
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Offline zeeprogrammer

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Re: Face Masks - a Public Service Broadcast
« Reply #14 on: April 08, 2020, 03:19:29 AM »
Zee:

I think I'd opt for running them through the wash. Probably not "sterile" but I think they'd be OK.

Thanks.

Hugh

The idea is to sterilize after every outing.

That's what they talked about on the news tonight. After every use.......wash in hot water.

Jim

So long as the water is hot enough to kill the virus. Boiling may be over the top but it tells people it's hot enough.
Carl (aka Zee) Will sometimes respond to 'hey' but never 'hey you'.
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