Sewing N95 Type Masks

To be clear, homemade masks will not be nearly as good as a real N95 mask and should only be used as a last resort.

Some additional info from the CDC. Apparently they investigated masks made from multiple layers of a heavyweight 2-ply t-shirt material.

1 Like

Nothing beats the genuine item. Instead of sewing one, using a kerchief is just as effective.
FYI wearing a face mask does not protect you from the virus. It will protect others if you are infected.

3 Likes

I do not believe the “does not protect you” part. I imagine it is more like it still means nothing if you do not wash your hands before touching your face. Of course, eyes should be protected from droplets too. Maybe that is what you were referring to?
I am tempted to make a full face bird mask design with plastic sheet windows for the eyes and a silicone caulk fitting for the edge. Just like what medics of ancient times used. I imagine coffee filters to contain charcoal and some jar lids with holes in them could make some air scrubbers.

1 Like

Yes and no. The N-95 mask is the only one that is approved to be worn around covid. I am mask fit every year to make sure I have the correct size and it fits correctly. This is done with a computer and hood that samples both the inside and outside air and compares to see if any contamination has occurred while talking and moving around.

1 Like

Here is a some information put out by Stanford Hospital regarding homemade mask materials and different ways actual N95 masks could be disinfected for reuse.

https://stanfordmedicine.app.box.com/v/covid19-PPE-1-1

1 Like

Thank you for sharing that! It’s not long, and it’s worth reading. Some quotes to encourage folks to read it;

In COVID-19, "50-75% of 3000 positive cases in Vo, Italy were asymptomatic according to Professor Sergio Romagnani. Risk of exposure grows exponentially as noted through actual exposures (charted internationally) N95 masks are warranted and remain the standard of care. While CDC has relaxed standards of care, their evidence cites risks of self-inoculation, cross contamination and pathogen spreading through direct and indirect transmission.

CDC recommends Standard Precautions should be followed when caring for any
patient, regardless of suspected or confirmed COVID-19. Doctors without borders
report COVID-19 infected healthcare workers surge to 8% in Italy with 1700 healthcare workers infected and recent report suggest this is climbing to 8.3% where PPE shortages are widespread.

Can N95 masks be autoclaved or sterilized by other means for safe reuse?

To be useful a decontamination method must eliminate the viral threat, be harmless to end-users, and retain respirator integrity.

4C Air confirmed all the proposed treatments have killed corona viruses. Labs have no way to test COVID-19 directly and as an accepted protocol, E. Coli is used for testing. We asked what methods can be used to decontaminate the facial mask for reuse safely and without loss to filtration efficiency. 4C Air confirms using 70 degree C hot air in an oven (typical kitchen-type of oven will do) for 30min, or hot water vapor are additional effective decontamination methods.

Conclusions: DO NOT use alcohol and chlorine-based disinfection methods. These will remove the static charge in the microfibers in N95 facial masks, reducing filtration efficiency. In addition, chlorine also retains gas after de-contamination and these fumes may be harmful.

2 Likes

I’m thinking that making full-face two-layer cloth masks, and making a low-temperature oven with insulation and a spare 3d printer heated bed (our kitchen oven doesn’t set as low as 70⁰C) might be useful. Not as good as N95, but for the occasional grocery store runs, might reduce virus count enough to matter, probabilisticaly speaking. But not wearing them long between change/sanitize because otherwise they could harbor bacteria, and the last thing I want to do is be the non-COVID walking pneumonia patient in a COVID-19 pandemic.

Most of the rest of my family is medical (either practicing or retired) and in the face of shortages my mother has been sewing multi-layer full-face masks with embedded wires to form the fit around the nose. Not expecting them to be better than N95, just some protection if proper PPE is not available. There’s enough research to show that they are better than nothing to make it worth the work, I think.

1 Like

Thanks for posting that.

I’ve got a few N95 masks left from a pack I bought for sanding and other dust generating projects. Also have a half face cartridge type mask I usually have activated carbon on for painting fumes, but have hepa carts I can put on it. They are all sized for me though. May see if I can get my Mom to sew some surgical type maks for my wife and daughter.

I think wearing masks out in public also has the benefit of preventing/reminding you to not touch your face.

Apparently some people touch their face more because of irritation from the mask.

I’ve asked for the pattern.

1 Like

I thought you might like to see this communication from our CEO at the hospital. It is the second to last paragraph that has WHO/CDC information. I have included the entire message for reference and clarity.

Dear Colleagues:

In our work to provide always better care – both to our patients and in caring for our colleagues and each other – we are grateful that we are not experiencing a shortage of PPE at this time. We are working far ahead of critical shortage to do everything we can to ensure we maintain adequate PPE supplies throughout this crisis. We ask all colleagues to continue to follow the guidance on the portal and the policies given to your by your leaders and your departments to ensure PPE is used appropriately. This way, together we can ensure safe patient care and preserve our PPE supplies.

At the same time, we understand many of our colleagues feel uncomfortable moving around the hospitals, facilities, cafeterias, and the like. Many of you have asked about wearing cloth masks – what other systems have called “social comfort masks” and what we will call “hallway masks.” There is no evidence that these masks are effective at stopping transmission of COVID-19, and they may increase risks to wearers of acquiring flu-like symptoms. However, for the comfort of our colleagues, starting today, when colleagues are not in a patient care area, they may wear a personal mask.

Here are the standards we will follow:

• Hallway masks may only be worn in hallways, cafeterias, and other public areas of our facility where patient care is not directly delivered. Any uncertainty about whether a particular space is a patient care area will be resolved by the CMO of the relevant facility.

• In patient care areas, colleagues are required to follow PPE policies with respect to everything from scrubs to masks and eye protection.

• Hallway masks must look substantially different than our PPE.

• Hallway masks must be kept clean and professional in appearance. Scarves and bandanas do not meet this professionalism standard and therefore are not permitted.

• Wearing a hallway mask is not a substitute for remaining at home if you are sick and do not satisfy masking required by Employee Health.

Please remember: CDC and WHO guidance states that continuous masking when you are well is not effective at preventing infection and may pose a greater risk to your health through self-inoculation. You also may transmit infection to others, even if you do not know you are sick, while wearing cloth masks, so please continue to adhere to all PPE guidelines, social distancing recommendations, and other efforts to help stop the spread of disease both in our facilities and in our communities. We are offering hallway masking as a personal choice for our employees because we recognize it will allow some colleagues to feel more comfortable in the workplace. Other colleagues may choose not to wear a hallway mask, and the personal decision of each colleague will be respected as long as the guidelines in this document are followed.

We will continue to work hard to secure PPE, explore ways to safely manufacturer evidence-based PPE, and constantly research and review options to keep our colleagues, our communities, and our patients safe during this crisis.

2 Likes

Saw this clever little hack for people having to wear masks a lot. Keeps your ears from being rubbed raw.

1 Like

The head of China’s CDC, an internationally-respected scientist and not a party flack, says:

Q: What mistakes are other countries making?

A: The big mistake in the U.S. and Europe, in my opinion, is that people aren’t wearing masks. This virus is transmitted by droplets and close contact. Droplets play a very important role—you’ve got to wear a mask, because when you speak, there are always droplets coming out of your mouth. Many people have asymptomatic or presymptomatic infections. If they are wearing face masks, it can prevent droplets that carry the virus from escaping and infecting others.

Those who are asymptomatic or presymptomatic do not know they are infected. The US CDC is right in rationing an unacceptably scarce resource, but for the general public wearing masks, we don’t need N95 masks. Surgical masks will do the trick, epidemiologically speaking. Widespread mask wearing isn’t to protect the wearer, but to protect others. Cloth masks may not eliminate aerosolized virus, but even the US CDC agrees they reduce droplet spread. Sterilizing them frequently to reduce the chance of auto-inoculation seems important. Since they don’t have the electrostatic fibers of N95 masks, many of the sterilization regimes that don’t work for N95 masks would work for cloth masks.

2 Likes

“It’s really a perfectly good public health intervention that’s not used,” argues KK Cheng, a public health expert at the University of Birmingham. “It’s not to protect yourself. It’s to protect people against the droplets coming out of your respiratory tract.”

Cheng and others stress that however masks are used, people must practice social distancing and stay at home as much as possible to prevent the spread of the novel coronavirus. When people do venture out and interact, they’re likely to spew some saliva. “I don’t want to frighten you, but when people speak and breathe and sing—you don’t have to sneeze or cough—these droplets are coming out,” he says.

Although there is some evidence that severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) can persist in aerosols—fine particles that remain suspended in air—aerosol transmission is likely rare, says Arnold Monto, an epidemiologist at the University of Michigan, Ann Arbor. It’s mostly spread by larger droplets, “and we know that standard surgical face masks will have a modest effect on that kind of transmission,” he says. “When you combine [masks] with other approaches, then they may make a difference.”

I saw somewhere that in Czechia the public awareness compaign has been "My mask protects you, your mask protects me."

1 Like

I understand how the general public is confused about using face masks and if it is or is not effective for viral transmission.

First of all, an understanding of what type of face mask to use for what conditions. Not all face masks are created the same. They are manufactured to specifications for specific uses. Not all masks are one size fits all. This is most important when discussing the N-95 face mask.

Masks do loose effectiveness after a period of time due to moisture and contaminates. People will wear a mask even indoors and too long so that they can have a negative impact on health.

Here are a couple of good reads.

2 Likes

And the mask need not be professional-grade to offer some benefit. In fact, officials say it probably shouldn’t be: The CDC recommends constructing your own cloth mask, so as to help ensure that doctors and nurses can obtain access to medical-grade surgical or N95 masks amid a widespread shortage of supplies.

1 Like

The government is trying to give the public what they want, the permission to wear a mask. They are also telling the public to make their own instead of using masks that can be used by health personnel.

The following are quotes from the conclusion in the article above, “Effectiveness of facemasks to reduce exposure hazards for airborne infections among general populations”

It was observed that fully sealed facemasks provide the highest protection, while the least protective was the normal wearing. It was also observed that the reduction of exposure decreases with increasing emission velocity and emission duration, and with decreasing separation distance between source and susceptible manikins. The current results have important implications for public health as wearing facemasks has become a common protection measure, particularly in some Asian countries.

The particles used in this study were spherical, but the shapes of viruses and bacteria are cylindrical or of some irregular morphologies. In this case, even with the same equivalent size, the behaviour of particles and viruses may be different.

In addition, the relative humidity (RH) should also be considered for follow-up studies, since wearing facemasks will undoubtedly increase the RH between the face and the facemask. Such further studies would be very important as the humid environment may provide a hotbed for viruses and bacteria.

I will conclude that numerous surgeons that I work with have stated that there are studies that wearing a mask during surgery does not limit the rate of infection in the patient. The surgeons have not stated whether the mask protects them from the patient! (In my opinion, after seeing every part and fluid of the human body end up on the surgical team in one form or another, at one time or another, PPE does protect the surgical team!)

BTW The COVID-19 virus is approximately 0.125 Micron in size.

2 Likes

Here is some addition information on the effectiveness of surgical masks. This one is from International Journal of Infection Control

There was no significant difference between cotton fabric and two ply disposable masks. Face
masks significantly decreased bacterial dispersal initially but became almost ineffective after two hours of use.

https://www.ijic.info/article/download/10788/7862/

2 Likes

Since I work in this field and find this a very interesting subject I’d like to add my 2 cents. Public Mask Wearing pro/Cons is a big discussion in Germany atm , too. Big Problem is that there are not nearly enough masks for medical staff left and one fear of mandatory mask wearing is that this situation will get much worse ( in the hospital I work in, nearly 2000 FFP2 Masks were stolen from the isolation ward over a time span of 2 weeks -.-. The amount of surgical masks who just “vanished” is much much higher).
There are several things to consider when discussing the safety of masks :
From what I learned in my university lectures on Virology and based on some recent studies (https://www.nature.com/articles/s41591-020-0843-2) regular face Masks (industrial ones) are effective in the control of bigger particles (>5μm) spread by the wearer. So as already mentioned by others in several posts earlier masks are most likely a tool to protect others from infectious particles spread by the wearer. Problem is that most regular masks have a lifespan of around 2h until they are soaked and become ineffective (as @HalfNormal already mentioned ). There is also a big discussion on the fact that wearing a mask may lead the warer to a false sense of security, thus neglecting the basic rules of infection control (distancing etc.). One other fact to consider is that the correct handling of face masks for non medical personal might be difficult. Face masks are only effective when worn correctly, nice example is that even a simple surgical mask, when worn correctly blocks >90% of infectios particles when it comes to influenza, but the rate drops <70% when the mask isn’t worn correctly (https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4680957/). Which leads us to the next problem, most studies regarding mask safety we currently have are for influenza or rhinoviruses (common cold), the one from nature I linked above at least uses other viruses from the Coronaviridae family so there might be similar results with Covid19. The infographic in the studies shows that mask effectiveness differs when it comes to different diseases.
So all this has to be considered when rating the safety and effectiveness of masks. Even the RKI (which is the somewhat equivalent of the CDC here in Germany) was strongly against the public use of face masks until a few days ago. Now they promote public wearing of self made masks with the statement that they might be effective when it comes to the amount of infectious particles spread by the wearer, but not as a tool of Personal safety.

5 Likes

@Aurelia Thank you for you input and insight. We have been told that any one leaving the hospital intentionally with more than a personal mask will be terminated on the spot.

2 Likes