A woman in a face shield with a gray long sleeve shirt.

U designs innovative respirator system

Julie Kiefer, associate director, science communications, U of U Health
June 29, 2020

A woman in a face shield with a gray long sleeve shirt.

U designs innovative respirator system

In response to the overwhelming demand for Personal Protective Equipment (PPE) due to COVID-19, the Center for Medical Innovation (CMI) at University of Utah Health has designed an enclosed Powered Air Purifying Respirator (PAPR) system to provide health care workers safe and reusable PPE when working with COVID-19 patients.


Designed to fully enclose the face of the user, a PAPR system consists of a hood or helmet and a filtered respirator to provide those wearing the system a constant flow of clean air. This positive pressure prevents entry of unfiltered air and protects the health worker from inhaling aerosolized COVID-19 particles.

However, due to the specialized nature of the equipment, hospitals typically have a limited quantity of the systems on-hand at any given time.

“PAPR systems provide excellent protection and can drastically reduce the consumption of single-use PPE, such as common N95 respirators,” explains Bryan McRae, interim co-director at CMI. “Unfortunately, PAPRs have now been unavailable for standard suppliers for more than a month. The CMI team and our University of Utah Health colleagues have been nimble and innovative in developing a solution to bridge the gap while traditional PPE sources remain uncertain.”

By combining readily available components such as mobile battery packs, portable fans and replaceable medical grade filters with several 3-D printed adapters, the assembled PAPR system designed by CMI expands the options to protect health workers treating COVID-19 patients.

The PAPR system on a table. The components are a plastic face shield surrounded by a white material that looks like a shower cap, connected to a long tube that plugs into a portable air filtration system.

The PAPR system is made by combining readily available components such as mobile battery packs, portable fans, and replaceable medical grade filters with several 3D printed adapters.

Using a standardized rating system known as “Fit Factor,” PAPR systems typically rate somewhere between 200 and 1000 on the quantitative fit testing scale. This means the system reduces the concentration of 0.3 micron aerosolized particles inside the system by 200 to 1000 times when compared to the air outside the hood. The PAPR system developed by the CMI was assessed by the Rocky Mountain Center for Occupational and Environmental Health at the University of Utah and offers a Fit Factor of 400 or better.

For comparison, on the OSHA scale known as an Assigned Protection Factor (APF), this PAPR offers an APF between 25 and 400, providing superior protection when compared to the common N95 respirator masks which typically only provide an APF of 10.

As the University of Utah Hospital braces for a potential surge of COVID-19 patients, all options to expand the supply of PPE are being explored. This includes retrofitting older pieces of still-viable equipment to the newer PAPR systems. Because of the customized 3-D printed adapter used to connect the respirator to the helmet, CMI’s PAPR system can also connect to older models of PAPR helmets still in-stock, enabling hundreds of previously unusable helmets to be worn safely and comfortably by health care workers at University Hospital.

Integrating feedback directly from those on the frontlines of COVID-19 management into the final PAPR system design, production has already begun to manufacture several hundred units as quickly as possible. Utilizing 3-D printing equipment on campus, including over 30 printers in production at the Marriott Library, Eccles Health Sciences Library and the College of Engineering, many of the PAPR systems will be ready for implementation within the week. Additional manufacturing support is being generously provided by O.C. Tanner and L3 Technologies.

“We are especially grateful for the expertise and insight from our university and industry partners,” said Bernhard Fassl, interim co-director of CMI. “As we further develop solutions for health workers during the COVID-19 outbreak, we will continue to rely on our community partners to help us implement these projects.”

Later this week, CMI will be releasing design specifications for the PAPR system to other health care groups and the public. This includes Indian Health Services and the Navajo Nation, as well as CMI’s global health partners in India, Kenya and Nepal, to provide guidance on assembly and use in resource-limited settings.

For more information about the PAPR system and the Center for Medical Innovation’s response to the COVID-19 outbreak, please click here.

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