Hello! I have been a doctor for 21 years. My name is Georgy Olegovich Sapego. In this article I will tell you about a standard homemade respirator mask and my own experience in making it.
Those anti-epidemic measures that we have discussed in the last two publications are approved by the World Health Organization and the American Centers for Disease Control.
The US Center for Disease Control understands that during the coronavirus epidemic, protective respirators and face masks can run out. Then you will have to use the means at hand. At worst, it is recommended to even use a scarf or bandana, which can cover your nose and mouth.
No one in their right mind would test such a thing in combat, so no one knew how it would be. So, putting on a homemade mask, you have to be extremely careful.
The Americans say that homemade masks are better than nothing, but ideally they should be used in conjunction with a transparent face shield. Such a flap should reach to or below the chin, and it should also go to the sides of the face. These are not my fantasies, but the official recommendations of the American Center for Disease Control for physicians who will work in conditions of limited resources.
Cotton-gauze bandages were used as far back as the century before last. Then in Asia there were epidemics of pneumonic plague, and people already guessed how to defend themselves. Cotton-gauze dressings are simple, but too varied. They are translucent, and there will be constant air leaks past them.
During the avian flu epidemic in the 2000s, the Americans developed a more or less standard mask from scrap materials that they offered to the military. Those have to deal not only with droplets of snot and saliva, but also with biological weapons such as spores or sprayed toxins. Therefore, the homemade mask had to be tight and fit well to the face.
It can be assumed that if such a mask retains a certain amount of small spores, then it will also retain large drops of snot from patients with coronavirus infection.
The mask is made from a knitted T-shirt. The shirt must be 100% cotton. The T-shirt is pre-boiled for 10 minutes to completely shrink the material and disinfect, and then air-dried.
This is important because jersey can stretch unpredictably and open holes for the virus. Plus, a T-shirt isn't the cleanest item, even if you just bought it. Someone could put it on or blow their nose into it.
You will need scissors, a marker and a tape measure. The mask consists of an outer layer measuring approximately 37 by 72 centimeters and eight small inner inserts (Figure 1).
Knitwear stretches differently along or across, so 8 inner layers are laid in pairs: 2 layers with fibers along and 2 layers with fibers across.
The top 14 centimeters of the wide outer layer is rolled in the form of a roll that overlaps the top edge of the pack of 8 inner layers. On this roller you need to make a small incision for the nasal bridge. Then, to the right and left of the nose on the cheeks, the roller will press well against the skin, and so there will be no air leaks (Figure 2).
The upper straps (A), which are in the form of a roller, are tied at the back of the head. Then the lower straps (B) from under the chin are lifted up and tied at the crown. Then the middle straps (B) are tied at the back of the head. So you need to achieve a tight fit without leaks.
This mask fits the face well, there are few air leaks from it, but it is difficult to breathe through it. Therefore, a homemade mask is not suitable for people with shortness of breath.
The effectiveness of the mask cannot be estimated in advance. It will depend on the material, individual features of the face or curvature.
With this mask, an interesting story turned out. It was developed as a standard and tested, but no one actually used it because Americans have always had protective respirators. The American Centers for Disease Control recommends this mask, but does not know how it will actually be.
Have you tried it? This is not cotton-gauze garbage. I ripped myself one T-shirt and made it. Gone is the entire size 50 T-shirt. Feeling like from an F-62Sh dust mask. I like it.
The weak point is near the bridge of the nose. An air leak is felt there. Make a good incision on the roller under the bridge of the nose. It seems that it is better to roll the top 14 centimeters roller onto the top edge of the stack of eight inner inserts. Then the roller will be thicker and can be modeled according to the width of the nose. My nose is broken, and therefore it is more difficult for me. Others may find it easier.
It also seems to me that the ties can be made more authentic, that is, the width of the workpiece can be taken not 72 centimeters, but 76 for example.
Read more of my articles:
Coronavirus and the disease it causes
Masks and coronavirus: how to wear and where to wear
