Engineer

Material options

We have received many questions regarding the ideal material options to use for the Origami Mask.  We are still exploring options, but our top recommendation at present is sterilization wrap.  This material is widely used in hospitals for sterilizing surgical devices and other reusable medical instrumentation.  Here is a link to Halyard's sterilization wrap. 

HALYARD STERILIZATION WRAP

Other manufacturers make similar products, and most have published data regarding filtration properties, air flow rates and other data pertinent to the Origami mask.  We received this material recommendation from healthcare providers at the University of Florida.  Here is a link to the article published on the topic:

SECOND LIFE: STERILE WRAP FASHIONED INTO MASKS

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  • re: sterilizing used N95 masks with ultraviolet light:   https://www.medgadget.com/2020/03/new-device-to-disinfect-500-n95-m...

     

    New Device to Disinfect 500 N95 Masks Per Hour
    Prescientx, an Ontario, Canada firm, has just started taking orders for a device that can rapidly disinfect N95 masks using ultraviolet (UV) light. By
  • Does anyone know how PENN's 3-day test run of the surgical wrap mask went? 

    • Hi Besty, can you be more specific?  I am not aware of a 3-day test run.

       

    • Hey Betsy - Penn Nurses and Docs have provided some of the initial feedback (that's many who are in the pictures on the website) but there was no three day evaluation period.  Feedback has been very positive from all evaluations.  All respondents stated the masks are very comfortable, and felt secure and safe.

    • DO you know if PENN has decided to outfit their entire medical staff (nurses, doctors, techs) with these masks?

       

    • We're not quite there yet, still many moving parts that need to be pulled together

    • I talked to Jon Kiel a week ago.  I thought he said that PENN was undergoing a 3-day trial run of the surgical wrap masks (origami based on University of Florida prototypes). 

       

       

  • Here's my thoughts on the paper from Eric (sorry if it's a tad lengthy). In short, thicker synthetic materials are more likely to add protection against transmission than thinner or cotton materials.

    The NaCl is a standard test used in NIOSH certification of respirators, and, as can be seen in the data, N95 masks prohibit the passage of NaCl particles far better than household items. An important consideration is that NaCl particles are a surrogate used just in testing (aka: they do no necessarily inform for specific applications because they are a component of a general test). In our case today we are interested in preventing COVID by stopping water droplets on the order of 3 microns from getting in the airways of individuals. The ability to stop salt penetrating isn't necessarily informative to us with no other data.

    At first glance, all the materials perform poorly, but in reality there is good and useful information we can pull from the data. While many fabrics were tested, only two main materials were analyzed, cotton and polyester. One fabric contained some %nylon, but given the weave pattern of most fabrics we can assume the polyester will dominate the material properties. Material type is important for our filtration because we want to prevent water droplets. Cotton will absorb water (they are hydrophilic, i.e. they like water), synthetic materials like polyester will repel water (they are hydrophobic, i.e. they do not like water). A first order choice says to use synthetic materials over cotton/cellulose materials.

    Inferring from the data approximate thicknesses of the fabrics (we can assume a towel is thicker than a shirt), we see that thicker materials generally perform better. Further, we can see that the Walmart fleece scarf far outperformed most other materials. From this we can say thicker materials that are synthetic are probably best and thick synthetic materials may be the absolute best. Granted, without appropriate testing we're just hypothesizing, but in a situation like this, sometimes that's all we have.

  • Engineer

    Attached is a publication from Oxford Academic that evaluates filtration performance of various houshold materials.  The origami maks pattern can be used with most household fabrics.  Please see attached publication for performance data.  

    Filtration Evaluation of Common Household Fabrics

  • Those prototypes were made using a MedLine equivalent. Based on what was available at our hospital. 

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