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My Continuous Effort in Coronavirus Infection Prevention- The Creation of Biosafety Soft-stretch Hoods

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I learned nonwoven manufacturing twenty-five years ago. I started by co-managing two polypropylene spunbonded nonwoven lines. My graduate study was not in fiber engineering; rather in plant physiology with intensive work on protein purification and some gene cloning and sequencing.To benefit my research, I took courses in biochemistry, molecular biology, and immunology. This academic training has enabled me to continue to follow and understand articles in medical journals, epidemics reports, and CDC posting. What I have learned has allowed me to develop effective protective apparel.

The lack of adequate equipment for primary head protection has been the problem in many daily jobs and in catastrophic events.My latex-free elastic nonwovens provide the breakthrough materials that gives a soft and stretchy structure excellent for making protective head coverings. Treating a piece of woven textile for multiple functionalities is difficult, if not impossible. However, by bonding individually treated elastic nonwoven fabrics into a multi-layer structure, apparel can be economically made with a combination of functionalities while maintaining softness and breathability. I have applied this concept in manufacturing a series of soft-stretch hoods (Dust Hoods, Spray hoods, UV Hoods, and BioSafety Hoods).

In the summer of 2014, I was developing an early version of Biosafety hoods for crime scene cleanup without noticing the worsening Ebola situation in west Africa. That September, medical workers in the US contracted the Ebola virus while caring for an infected patient. Subsequently, more than 3,000 purchase orders were received in a three-week period. With limited inventory, we had to prioritize our supply to VA hospitals and the military. Still, we sold out all our hoods before the end of October. In the following years, I enhanced our Biosafety hoods with functionality of blocking blood splashes. In late fall of last year, another advanced version with alcohol repellency was added. However, before the completion of an expansion in 2021, the current capacity may only last for a few months in dealing this latest outbreak.

Our BioSafety Hoods are engineered to provide effective protection with an innovative advantage of “COMFORT”- (1) soft form-fit tosecurely cover the entire head, face and neck without restricting head movement and wearer’s mobility. (2) easy breathability for extended wear.

Airborne particles (without high pressure force) cannot penetrate the structures of our Biosafety hoods. Meanwhile, the ultrafine gaps between fibers allow body heat and perspiration to escape which keeps the head cool. Workers can comfortably wear our hoods all day for continuous protection.The design of our full-cover hood forms an air-pocket around the nose and mouth to serve as a facemask. The dense, 12 layer, fiber-composite structures were engineered to filter 95% of bacteria (ASTM F2101) and 95% of 1-micron particles (ASTM F2299).The efficiency of filtering submicron particulates is even higher (>99% for 0.1 micron) because submicron particulates are mostly attracted by static and attach more tightly to the surface of fibers.

The structures of our Biosafety hoods are qualified as level 1 liquid barrier (ASTM F1862) engineered to block body fluids or blood splashes, which is for protecting medical workers in conducting surgical operations such as intubation.To provide comfortable breathability for extended wear, the delta P was kept under 4 mm H2O/cm2. For reference, the delta P of high filtration surgical masks and disposable N95 masks is around 5 and above 20, respectively.

The suggested donning sequence is to put on our hood first, followed by goggles to protect the eyes. It is essential to select goggles that fit the wearer’s face curve for sealing around the wearer’s nose and allowing it to press firmly on the wearer’s nose bridge.Our hoods can be worn comfortably under a face mask or full-face respirator. In case the mask/respirator moves, our hood can provide an additional layer of barrier for continuous protection.

In extreme situations when PAPR (powered air purification respirator) is required, wearing a Biosafety hood under the PAPR or hazmat hood provides continuous protection after removal of the contaminated suit. Our Biosafety hoods should be the first PPE put on and the last removed.

Our hoods are also effective in contaminants control when worn by infected patients. Double layering our hoods is recommended to contain spittle expelled from talking, coughing and sneezing.

Our hoods are very affordable, $2.70-$3.50 each. They are well constructed and reusable. They can be conveniently sterilized by soaking in commercial bleach concentrate for 5 minutes followed by rinsing them in clean water and airdry or in dryer with low heat for 10 minutes. To ensure the durability our hoods, we have tested washing them in industrial washing machine over 15 cycles of 30 minutes with warm water and tumble dry at low heat (130F) for 10 minutes.

Our Hoods are replacing facemasks for more practical and economical protection in many work environments. There is only one elastic nonwovens process line (which was built by DuPont at VitaFlex’s plant in Burlington, North Carolina) and I am the scientist to continue developing elastic nonwovens and soft-stretch protective hoods.