How to Create an N95 Mask Disinfection Facility for Less Than $15,000

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By Mandy Roth

The COVID-19 crisis has spawned a new era of innovation at hospitals and health systems to adapt to changing demands. Inspiration comes from many sources.

In Richmond, Virginia, an anticipated N95 mask shortage at VCU Health sent orthopaedic surgeon Stephen Kates, MD, into his personal machine shop, where he has fabricated items for the operating room, his car, and even parts for a friend’s old Ford tractor. This time, working with an anesthesiologist, two residents, and two PhDs from Virginia Commonwealth University, the professor and chairman of orthopaedic surgery produced a trellis rack to hang and sterilize masks with UV-C light. The design amplifies an already proven sterilization process, enabling high throughput. The health system is now using the system to decontaminate and reuse up to 12,000 N95 masks a day.

The process is based on a concept from the University of Nebraska and adheres to Centers for Disease Control and Prevention guidelines. It involves a commonly used UV-C light robot that VCU already had on hand to decontaminate hospital rooms, and employs materials which the VCU team sourced from The Home Depot, Lowe’s, and a tractor supply store.

To help other health systems replicate this initiative, Richmond, Virginia–based VCU Health, which includes an academic medical center and is affiliated with Virginia Commonwealth University, offers a free 28-page downloadable instruction manual. The booklet outlines each step in the process, including quality controls with pictures and a video link providing added details. Kates estimates a similar system can be fabricated for as little as $15,000, provided a facility already has a proper UV-C light source that can be redeployed for this purpose.

Behind the innovation

Kates was called into action by a group from the university, which had produced a white paper on the topic of disinfecting N95 masks. While other methods exist to sterilize the masks, including hydrogen peroxide vapor, VCU Health chose UV-C light because it relies on electricity rather than supplies that might run short during the pandemic. In addition, exposure to the light source does not structurally degrade the mask as quickly as other methods, Kates says.

“The concept of sterilizing things with UV lights is not new; we didn’t come up with that,” says Kates. “The question was, ‘How to you actualize it and make it work?’ ” he says. “How do we have a high throughput process that can deal with a surge of patients that otherwise is overwhelming health systems across the country?”

“Making stuff out of metal is a hobby of mine, so I went to work on it that day and made a sample,” he says. “Everyone liked the appearance of it, so the next day we made seven more. Once we found a good design, we had local welders and machinists fabricate the rest of them.”

Ramping up production

VCU created a mask decontamination facility in a building adjacent to the hospital and painted the treatment room with reflective white paint at the recommendation of its UV-C robot manufacturer, Tru-D, to facilitate light measurement. The final design includes six racks on wheels, each containing 42 masks. The racks are arranged in a hexagonal pattern around the robot.

The procedure includes two exposures to a thousand millijoules of UV-C light to treat both sides of the mask. “It takes somewhere between one and seven millijoules of light to kill a single-strand RNA virus like COVID,” says Kates, “so we’re giving approximately 500 times more light than is needed. We’re making sure there’s nothing alive on that mask when you get done with it.”

Two dozen people work at the facility, redeployed from other jobs at VCU Health.

While the manual details each step involved in the process, some highlights include:

  • Employees are encouraged not to use moisturizer, foundation, or lipstick, which limit reuse of masks.
  • To provide a level of comfort to employees, masks are labeled with the employee’s name, so individuals reuse their own equipment.
  • Used masks are placed in brown paper bags and placed in a red collection bin in each unit or department. Using paper bags may be helpful in reducing mask moisture content, says Kates.
  • Each time a mask is sterilized, a hashmark is placed on the item, making it easy to track how many times it has been decontaminated.
  • Masks are returned to each unit in a clear plastic bin.

Quality control is essential

To properly decontaminate masks, quality control is essential, says Kates, who used lean manufacturing principles to refine the process. “Lean processing is a personal interest of mine, and I taught it at the business school when I used to live in New York,” he says. “One of the manufacturing principles is to make sure that the defect never reaches the customer, and the customer is our employee.”

Among the quality controls VCU Health has instituted:

  1. Masks undergo an initial inspection to ensure they are structurally intact and free of makeup, blood, or other substances.
  2. Moisture content is measured on a sample of the masks. High moisture is not conducive to mask reuse.
  3. Breathability studies with a vacuum are conducted on select mask samples in which air flow is measured.
  4. The process includes two separate light measurements. One is derived from the UV-C light robot, which is recorded onto an iPad. In addition, there is an additional light meter attached to the rack with a magnet that offers an independent measure. The device is connected to a desktop computer outside the room and demonstrates in real time how much light is being delivered to the masks.
  5. Fit testing is performed on selected samples of masks, which involves spraying saccharin into a special device placed over the head of a tester wearing the mask. If they taste the substance, the mask no longer fits properly.
  6. Finally, a small sample of the masks are selected for destructive testing.

“We’ve done all of these quality controls, every day, on the masks,” says Kates. “The goal is to reassure the employees who are wearing the mask that it’s safe and it’s still doing its job.” If any failures occur, the masks are discarded. Because VCU Health just started using the system, data is not yet available to measure the impact this has had on the system. As with most COVID-19 innovations, many processes are being created on the fly.

Meanwhile, the process is allowing VCU Health to reuse masks that are in short supply elsewhere. “I can confidently say we’ll get through this crisis and the surge, and no matter what happens, our employees will have masks to wear.”

Mandy Roth is the innovations editor at HealthLeaders.