Q&A on UV-C Disinfection for Healthcare and Non-Healthcare Settings

On March 9, 2022, R-Zero hosted a webinar to explore UV-C disinfection for healthcare, education, senior care and other non healthcare settings with two of the nation’s leading UV-C experts: Dr. Edward Nardell, a Professor of Medicine at Harvard Medical School, and Dr. David Brenner, Director of the Columbia University Center for Radiological Research. Dr. Nardell and Dr. Brenner presented on upper room germicidal UV (GUV), sometimes also called upper room ultraviolet germicidal irradiation (UVGI), and Far-UVC applications in healthcare settings before responding to questions from webinar attendees. Time didn’t allow for answers to all the questions participants posed, so we have compiled the questions and responses in the following blog post.

The Basics of UV-C (Ultraviolet-C) Disinfection

How does UV-C disinfection work? What are the benefits of uv-c light for disinfection?

UV-C is invisible light with a bulb wavelength between 200nm and 280nm. UV-C damages the DNA and RNA of microorganisms and disrupts vital cellular functions, preventing these microorganisms from replicating or spreading. The germicidal properties of UV-C towers, lights and lamps have been studied and proven for over 100 years, and researchers have published thousands of peer-reviewed studies proving UV-C’s germicidal efficacy.

What is the difference between and benefits of UVGI and Far-UVC?

Within the spectrum of UV-C light, there are different wavelengths of light whose use cases vary.

Upper room ultraviolet germicidal irradiation (UVGI) or upper room germicidal UV is one application that may use 254nm or 265nm UV-C light to disinfect the air in the upper portion of an occupied space.

As air naturally rises, the air passes through an ultraviolet irradiance zone and is disinfected. UV-C towers for unoccupied spaces may also use GUV or UVGI at 254nm or 265nm. Far-UVC applications most commonly use 222nm UV-C light to disinfect the air and surfaces in an occupied space. Unlike other wavelengths of UV-C light, Far-UVC cannot penetrate the outer layers of human skin and eyes and is consequently safe for human exposure – hence its use in occupied spaces.

How often does a room need UV-C to remain disinfected?

The necessity and frequency of UV-C disinfection requirements depend on how a space is used and the UV-C device deployed in that space. UV-C towers for unoccupied spaces have varying cycle durations and can be deployed on an as-needed basis to help with incident management. For example, R-Zero’s arc whole room UV-C disinfection can treat an unoccupied, 1,000 square foot room in just seven minutes.

By contrast, UV-C devices that use upper room GUV or Far-UVC may be designed to continuously and autonomously disinfect a space based on occupancy and utilization. Given the different use cases for different spaces, a combination of installed fixtures that disinfect continuously and autonomously and portable devices that can achieve whole-room disinfection in a matter of minutes may be best for dynamic environments.

Are there any guidelines for the safe handling of UV-C products?

Far-UVC is safe for human exposure, so devices that employ Far-UVC light do not require any special handling guidelines or robots. Upper room GUV devices should not require special handling instructions since they are often fixtures mounted closer to the ceiling in a room where people are present. By contrast, UV-C towers may have multiple built-in safety mechanisms to prevent potential exposure to the more damaging light they emit. For example, R-Zero’s Arc device includes redundant safety measures and sensor technology to ensure that if a person were to walk into a room while a cycle is running, the device will automatically shut off. 

What regulatory bodies govern the use of UV-C disinfection? Is the CDC affirming UV-C’s effectiveness? 

UV-C devices are regulated by the FDA. In addition, the CDC, ASHRAE, and WHO have all  acknowledged UV-C as a valid disinfection method. Within the UV-C industry, the International Ultraviolet Association (IUVA) also functions as a thought leader and provider of education and resources on UV applications.

Applications in Healthcare

Are there any examples of UV-C applications in a dental setting? 

Researchers have explored UV-C in dental practices. For example, an Italian study of alternative disinfection methods deployed in a dental setting noted that “UV-C systems have numerous advantages” versus other methods, including ease of use and speed. Another study out of Brazil suggested that UV disinfection in dental offices could be an effective disinfection protocol during COVID-19. 

What are the recommendations for the use of UV-C technologies in multi-bed patient room settings or shared patient spaces?

UV-C can be used to augment existing ventilation in occupied spaces or to achieve whole-room disinfection in unoccupied spaces. In a recent article for TIME, Dr. Nardell noted that UV applications have been used in healthcare settings for decades. He wrote, “[GUV] was widely used in U.S. health care settings before the discovery of antibiotics for tuberculosis, and vaccines for the childhood viral infections, measles, mumps, and rubella. Renewed interest in GUV in health care settings, homeless shelters, prisons, jails and other congregate settings followed the 1985-92 resurgence of TB in the U.S. and Europe.”

What advantages does UV-C disinfection present versus air filtration?

While air filtration is effective at filtering out airborne contaminants, it only captures rather than kills airborne microorganisms. By contrast, UV-C is proven to inactivate 99.99 percent of microorganisms. Furthermore, upper room UV-C or upper room GUV can inactivate rather than just capture airborne microorganisms before they can spread. In addition, GUV or upper room UVGI can treat a large volume of air at once, is not flow-limited like ventilation, and doesn’t require air capture to treat the air.

How can UV-C technology replace certain cleaning practices such as electrostatic spraying?

Chemical exposure can damage the lungs, skin, and eyes. Disinfecting with UV-C light offers 15 times less risk and is twice as effectiveness over electrostatic spraying by increasing efficacy, and reducing the acute hazard potential of chemical exposure.

Given Far-UVC’s efficacy on bacteria, what impact might Far-UVC have on natural, healthy skin microflora? 

The human microbiome is tough, particularly the skin microbiome. Human skin is exposed to scrubbing with antimicrobials, skincare products, sunshine and environmental conditions, and more. Vive far UV light C does not pose any greater risk to human skin or the human microbiome than the risks posed by typical human behavior and sun exposure.

Are there potential issues with drug-resistant organisms that might be able to spread more rapidly if natural flora are reduced by UV-C light?

Drug-resistant organisms become drug-resistant because some particular location inside the bacteria has mutated, making the bacteria resistant to some particular drug. They have to be introduced into a body where they can be exposed to antibiotics in order to become resistant. By contrast, UV-C does not target specific locations in bacteria. UV-C causes random damage within a microorganism’s DNA or RNA. Consequently, drug-resistant organisms are still susceptible to inactivation by UV-C. In fact, some studies have found that the addition of UV-C light to manual cleaning in healthcare settings can reduce the MDRO burden in the patient room environment.

How do UV-C applications help with infection that happens in the close range, e.g., if an infected individual is in the vicinity of another uninfected individual?

The efficacy of UV-C to address close-range infection is somewhat unknown and difficult to study experimentally. When a droplet has only a few microseconds to travel between individuals in close proximity to one another, crowding together or even sharing air, environmental interventions are going to be less effective. 

Questions about R-Zero Products 

With so many device choices, what is the best way to understand and identify the UV light products and vendors best suited to an organization’s needs? 

Understanding how UV-C can fit into disinfection protocols is important. Ideal UV-C partners are vendors that can identify how to integrate with existing janitorial processes, provide options, and offer solution customization for maximum efficiency and effectiveness. 

How does R-Zero’s technology determine the amount of time needed to disinfect a room? What square footage can R-Zero’s solutions disinfect?

R-Zero’s implementation team works with each customer to develop a customized plan for disinfection that ensures effectiveness and efficiency. Based on room sizes, uses, and occupancy, R-Zero will recommend the most effective locations and placements for our devices. Different devices can be suited to different spaces. For example, R-Zero’s flagship product, Arc, can disinfect a 1,000 square foot unoccupied room in just 7 minutes while inactivating up to 99.99 percent of microorganisms. Beam upper room UVGI disinfection and Vive can disinfect continuously and autonomously in occupied spaces.

Are R-Zero’s UV-C products independently validated/tested? 

In addition to the testing performed by R-Zero’s product development team, R-Zero partners with independent, third-party labs to test and validate products. Reports are available upon request.

What sets R-Zero’s solutions apart from other UV-C device vendors?

R-Zero combines best-in-class UV-C technology and data to create an ecosystem unparalleled in efficacy and sustainability to fundamentally change the health of any building. R-Zero’s best-in-class ecosystem of UV-C disinfection technology can help reduce the risk of exposure to harmful microorganisms in indoor environments, thereby providing peace of mind for patients, staff, and visitors.

What type of maintenance is required for these units? What about dust collecting on bulbs: does this impede the light emission?

Maintenance requirements for R-Zero’s UV disinfection devices are minimal. Bulbs are long-lasting and require infrequent bulb changes. Occasionally dusting the device is helpful as part of regular care.

R-Zero is proud to partner with experts like Dr. Nardell and Dr. Brenner to advance the field of UV-C disinfection. If you would like to learn more about R-Zero’s suite of UV-C disinfection solutions, contact us today.