IndiAdamJones and the Quest for the 3D Printable Respirator

For my own personal use, I bought a 3M 6200 half-face respirator with P100 cartridges that I scored on Ebay back in early January when the coronavirus jumped borders for the first time. I bought a pair of masks w/ one set of filters each.  With shipping I paid ~$30 USD.  Now, anyone currently following the ‘mask hysteria’ knows that doctors currently recommend mask for infected patients only.  They say a mask limits the spray from coughing and sneezing in a patient, but won’t inhibit infection in a healthy person, as this behavior increases the likelihood you will get coronavirus from touching your face when adjusting the mask.  Also, they claim a shortage of available supplies for medical personnel. The surgeon general even got quite adamant about it, ordering people to stop buying masks.

However, while pleading with the public to stop buying protected breathing equipment, they also put out infographics advising us on how to shave, in order to achieve a better seal around the mask.  If that isn’t a contradiction in terms, I don’t know what is.  How are you gonna tell us we don’t need a mask, we just need to shave our face so it doesn’t leak?!?

LOL, take a deep breath, oh wait don’t.  Let’s start with some definitions before we turn an already bad pandemic into a miscommunication of dire consequence, shall we?

PPE (Personal Protective Equipment) Vocabulary

dust mask, n95 mask, respirator

Dust Mask – (top left, image above) This is your standard dust mask for stopping large particulates.  It’s got a metal tab along the top to bend around the bridge of your nose for a slightly more custom fit.  A dust mask will seal around one’s face based on the shape of the mask where it meets the shape of the face.  It attaches using a single elastic band.  Intuitively, I’d rather have this than nothing at all, but American doctors say no!  They think a mask like this increases the risk of infection via face-touching.

N95 Mask – (top right, image above) You will see a lot of people with a more serious looking dust mask.  These masks get composed with a material rated to filter very small particulates.  It’s basically just a dust mask made out of filter material, with two elastic bands.  One can expect less seepage around the mask edge with two elastic bands, but still not air-tight.  This solution seems good for basic protection, but you still would need to avoid smearing the virus into mucus membranes while unconsciously repositioning the mask.

Half-Face Respirator – (bottom, image above) Now, let’s look at a respirator.  It’s like a gas mask, without eye protection.  The respirator gets pretty close to an air-tight, or hermetic seal around your face. The adjustable straps allow for a snug fit, with little need to adjust the mask once fitted.  The siliconized rubber improves an air-tight seal.  Inhaling causes a negative pressure, drawing air in strictly through the filters.  The replaceable filters come in a variety of different flavors depending on what kind of work you need to do.

face mask with exhalation valve

Exhalation Valve – Masks and respirators clean your inhalation through filter material, but what happens when you exhale?  Many include an exhalation valve, which operates as a one-way valve allowing effortless exhalation.  The design of the exhalation valve limits aerosol by physically redirecting the flow of air, and I suspect it can still expel aerosol dropplets with the hitchhiking coronavirus.

Further Resources for Respiratory Protection

https://www.sciencedirect.com/science/article/pii/S1438463917308003 – This report gives an incredibly in-depth account of the data associated with respiratory protection.  An excellent resource for science-minded individuals who prefer accurate data.  This particular study looked at the effectiveness of commerical and ad hoc respiratory protection against Volcanic ash.  You can also view or download the PDF directly.  One noteable data observation: wetting filter material, as sometimes advocated,  degrades effectiveness.

Ad Hoc 8 Layer T-Shirt Mask

If you can’t find a mask or respirator, please don’t panic.  You can easily fashion one out of other materials.  Take a look at this study conducted with a t-shirt mask.

8-layer t-shirt mask

OpEd to OpenSource

You’d think someone would hold these officials’ feet to the fire on this important issue of how the mask affects contagion, but we, the citizenry, get left to decipher on our own a seeming contradiction of great import.  Constantly we see images of people in masks, and hear about hospital works getting infected through PPE.  Does anyone besides me think the hospital’s holy-grail medical personnel should exclusively use respirators?  Shouldn’t our high-risk demographics (>60 years old), get respirators and wear them consistently?

The virus can transmit through aerosol, or via the moisture in heavy breathing, coughing, and sneezing.  The issue I keep considering sounds something like: If someone sneezes and the wind picks up, then doesn’t aerosol turn airborne.  At least over short distances, I suspect the wind can carry coronavirus, just as mist from a spray bottle can travel laterally.

Depending on the risk level in your area, one needs a respirator to stand a chance against the virulent coronavirus.  What a perfect little design challenge for my fledgling industrial design operation, only…I’m struggling to get a prototype working.  It’s at this point that I want to work on some of the opensource features of this project, in hopes that the work can involve anyone with the required skill to produce an adhoc respirator.

Current 3D Printed Respirator Solutions

I always check the available solutions first, which in the case of a 3D printed respirator, left me wanting.  Still, we do have a few entries which I will make available below.  If you can get a half-face respirator, even without filters, you are better off from a 3D printing perspective since you can print cartridge replacement housing.  Then you just need to source your filter material.

Since the human face appears in such at variety of subtle shape, it can get difficult for one design to accommodate everyone.  Hence the field of ergonomics factors strongly into any design intended to satisfy the variance.

 

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