Sunday, March 15, 2020

COVID-19, And A Simple, Homemade Respiratory Mask ©


 
An excerpt from “Simple Respiratory Mask”, page 1033
For a video demonstrating how to put on the mask built according to the study a "Simple Respiratory Mask", go HERE or HERE, -- Author's Note  

With the current concerns over the COVID-19 and shortages of masks, and with the sincere hope that you never need this information, I am writing this article.  I am not an alarmist, I haven’t bugged-out for the woods...yet, laugh out loud!  I like to read about prepping though, my Father says that I would stop to read soup labels and he’s probably right.  I am also not a doctor and I don’t even play one on TV.  I just read a lot and I found this article several years ago and thought that I would pass it on to you. 

I am not saying that you need to stockpile N95 masks or make homemade, simple respirator masks because of the coronavirus, however “forewarned is forearmed1 and it never hurts to know how to do things.  A simple homemade respiratory mask, equivalent to a N95 mask, made with locally available materials, which can be washed and sterilized with methods available worldwide, “...may be a solution if commercial masks are not available2. 

However, before I begin I need to share the opinions and disclaimers of the CDC with regards to this article, since it was published on their web site: “The conclusions, findings, and opinions expressed by authors contributing to this journal do not necessarily reflect the official position of the U.S. Department of Health and Human Services, the Public Health Service, the Centers for Disease Control and Prevention, or the authors' affiliated institutions. Use of trade names is for identification only and does not imply endorsement by any of the groups named above3.  So, draw your own conclusions from the material below, I am not offering medical advice and I do not represent, endorse, guaranty or warranty this information: it is simply provided for your continuing education and enlightenment.

 
Photograph by the author.

There are two types of face masks, and the air purifying respirator masks like the N95 masks offer more protection than a simple disposable medical face mask or a surgical mask, both of which are generally loose fitting.

Disposable face masks simply create a barrier between your nose and mouth and splashes or large particles and droplets.  They cannot filter out the very small particles or droplets that are created when people talk, sneeze or cough.  They also do not fit tightly around your face and therefore, they allow air to leak under the mask and into your mouth and nose.  This type of mask, by definition, is disposable and if they become damaged, dirty, soiled or stained they should be disposed of and replaced with a new mask.

The U.S. Department of Labor recommends air purifying respiratory masks, either N95, N99 or N100 masks for workers working with victims of viruses.  Remember viruses like the corona virus, COVID-19, spread when infected people sneeze, cough or talk, spewing droplets containing the virus into the air and possibly into the eyes, mouth, nose, throat or lungs of a nearby person.  The greater the N-value of a mask, the greater the protection a properly fitted mask provides: N95 respiratory masks are 95% efficient at filtering the 0.3µ (micron) particles created when people talk, sneeze or cough.  Another thing to know about N95 masks is that they can be fatiguing to wear, the authors of a “Simple Respiratory Mask”, noted that while the testers wore this mask for an hour without any difficulty, they could not comment on what it was like to wear while performing strenuous work or in adverse environments.

 
Photograph by the author.

To make this simple respiratory mask you will need a heavy-weight T-shirt.  The authors of this study used a Hanes Heavyweight 100% cotton T-shirt made in Honduras, I used a Gildan Ultra Cotton, 100% pre-shrunk T-shirt, made in Nicaragua.  You will also need a pair of sharp scissors and a ruler or tape-measure, and a magic marker doesn’t hurt. 

Before beginning, boil the T-shirt for ten minutes and then air dried it, this maximizes shrinkage and sterilizes the cloth: this method of sterilization is available worldwide.
 
An excerpt from “Simple Respiratory Mask”, page 1033
   
Step One: The Outer Layer

To make the outer layer, you need a piece of T-shirt that is 14-½ inches tall to just over 28 inches long (37 cm tall by 72 cm long).  I found that if I cut upwards to the bottom of the sleeve and then around the back of the T-shirt to the bottom of the other sleeve and then another 5 inches (about 13 cm) further around towards the front of the shirt, I would end up with a piece of cloth with the correct dimensions.






 
Photographs by the author.
  
Step Two: The Inner Layers

In this step you will make the eight inner layers for the simple respiratory mask from pieces of T-shirt that are 7 inches tall by 7 inches long (18 cm tall by 18 cm long).  I found that I was able to cut out three of the inner layers from the material on the back of the shirt between the sleeves.  The other five pieces came from the front of the shirt. 

If you have a wide face, the authors of this study, suggested that you make and use inner layers that are larger than 7 inches square (18 cm by 18 cm square), so that you will have less air leakage when you wear the mask.




 
Photographs by the author.
  
Step Three: Making the Ties

This step is the easiest.  First, I assembled the inner layers; two layers cross-grain, two layers straight, or lengthwise-grain, two layers cross-grain, and finally two more layers laid straight-grain.4  I placed the assembled inner layers onto the bottom center of the outer layer.


 
Photographs by the author.

  
Next, I measured down 5-½ inches (14 cm) from the top edge of the outer layer and then made a 9 inch (23 cm) long cut in towards the center of the outer layer, I did this on both sides  This creates tie “A” which is then rolled down, in a roll that is about 1-¼ to 1-½ inches wide (32 to 38 mm), stopping at the top edge of the inner layers.  Measure up from the bottom edge of the outer layer by 6 inches (15 cm) and then cut in toward the center on both sides, making a cut 9 inches (23 cm) long; and these two cuts create ties “B” and “C”
 
Photograph by the author.
  
Step Four: Making the Nose Slit
 
An excerpt from “Simple Respiratory Mask”, page 1033






 
Photographs by the author.
  
Make a “nose slit” for the bridge of your nose in the center of tie “A”.  Measure in from either edge about 14 inches (36 cm) and make a slit about a ¼ inch (64 mm) from the top and bottom edge of the 1-¼ to 1-½ inches wide roll that is tie “A”.  This slit should be 1 inch long (25mm) and penetrate through no more than three layers of tie “A”.
 
An excerpt from “Simple Respiratory Mask”, page 1033
  
Now that the mask is made it is time to put it on.  I found that it is easier to put the mask on in front of a mirror.  Start by putting the “nose slit” in tie “A” over the bridge of your nose and then tie, tie “A” below the back of your neck.  Adjust the fit around your nose and cheekbones to eliminate any air leakage.  If the seal is not tight and there is air leakage, the authors of a “Simple Respiratory Mask” suggest that you push the rolled fabric of tie “A”, up or down on your cheekbones until the leakage stops.  If the seal is still not tight the authors further suggest that you push extra T-shirt material under tie “A”, between your cheekbones and your nose.  I cut out an extra 7 inch by 7 inch (18 cm by 18 cm) piece of T-shirt to use as an air leakage cloth.
 
Photograph by the author.
  
Next tie, tie “B” over and on top of your head.  If the ties are too short, knot extensions to each end of tie “B”.  I cut out extensions which were 3 inches wide by 9 inches long (8 cm wide by 23 cm long) from the remains of my T-shirt.  These are about the same dimensions as tie “B” and should give you plenty of length to knot this tie over your head.

And the last step in putting on this mask, is to tie, tie “C” behind your head and voila, you are masked.
 
Note the roll of cloth, just visible on the bridge of my nose, tucked under my mask to stop air leakage
 
Photographs by the author.
  
The authors of a “Simple Respiratory Mask” noted that commercially available N95 respirators required a fit factor of 100 against aerosol contaminants to be considered adequate in the workplace.  The homemade mask featured in the “Simple Respiratory Mask” study, achieved with one author, a fit factor of 67 and a fit factor of 13 and 17, with the other two authors, who had larger faces.  The authors felt that this homemade N95 respiratory mask would have a lower fit factor and therefore be less effective than commercially manufactured N95 respiratory masks.  They felt that this would be especially true when these homemade masks were made by amateurs.  Additionally, they thought there might be problems due to variations in locally available materials, cultural practices, facial structures, beards, etc.  It should be noted that when using any respirator, you need to be clean-shaven...sorry guys!  The authors of this study did not recommend using this homemade mask in place of a commercially manufactured N95 mask, however they did feel that this homemade mask provided a good fit and a measurable level of protection from aerosol contaminants.  In the end it comes down to “something is better than nothing”.

I hope that you continue to enjoy The Woodsman’s Journal Online and look for me on YouTube at Bandanaman Productions for other related videos, HERE.  Don’t forget to follow me on both The Woodsman’s Journal Online, HERE, and subscribe to BandanaMan Productions on YouTube.  If you have questions, as always, feel free to leave a comment on either site.  I announce new articles on Facebook at Eric Reynolds, on Instagram at bandanamanaproductions, and on VK at Eric Reynolds, so watch for me.

That is all for now, and as always, until next time, Happy Trails!


Notes

1Forewarned is forearmed” means that you can be appropriately prepared if you know something in advance.  Knowledge in advance enables one to be prepared in advance. This expression originated as a Latin proverb, Praemonitus, praemunitus, which was translated into English by the early 1500s as “forewarned, forearmed”, and it has a similar meaning to the saying “a word to the wise”.  From the Free Dictionary by Farlex, https://idioms.thefreedictionary.com/forewarned+is+forearmed and The Phrase Finder , https://www.phrases.org.uk/meanings/forewarned-is-forearmed.html

2 Virginia M. Dato, David Hostler and Michael E. Hahn, “Simple Respiratory Mask”, page 1033

3 CDC, Center for Disease Control and Prevention, Emerging Infectious Diseases

4 According to the web site, The Spruce Crafts, “What Is a Fabric's Crosswise Grain?”, cross grain is “The crosswise grain of a piece of fabric is a term that describes the threads that run perpendicular to the length of fabric as it comes off the bolt”, this grain runs across the width of the cloth.  Therefore, straight or lengthwise grain of a fabric is the term that describes the threads that run parallel to the length of the fabric as it comes off the bolt.


Sources

CDC, Center for Disease Control and Prevention, Emerging Infectious Diseases, June 2006, Volume 12, Number 6, https://wwwnc.cdc.gov/eid/article/12/6/05-1468-f1, accessed March 5, 2020

Dato, Virginia M., Hostler, David, and Hahn, Michael E. “Simple Respiratory Mask”, Emerging Infectious Diseases, June 2006, Volume 12, Number 6, p. 1033-1034. https://dx.doi.org/10.3201/eid1206.051468, accessed March 5, 2020

Kekatos, Mary; “Mask mania”, February 27, 2020, Dailymail.com, https://www.dailymail.co.uk/health/article-8051799/Can-face-mask-really-protect-against-coronavirus.html, accessed March 5, 2020

Wickell, Janet; The Spruce Crafts, “What Is a Fabric's Crosswise Grain?”, https://www.thesprucecrafts.com/what-is-a-fabrics-crosswise-grain-2821571, accessed March 10, 2020


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