Interviews + Opinion

PNNL’s Gabe Arnold Talks Upper-Air GUV

For an upcoming article for ELECTRICAL CONTRACTOR, I recently had the opportunity to interview Gabe Arnold, PE, Senior Systems Engineer for Pacific Northwest National Laboratory (PNNL). The topic: a new ACEEE conference paper evaluating the efficacy and energy consumption of upper-room GUV systems. Transcript follows.

DiLouie: PNNL recently produced a paper evaluating the relative energy impacts of various Covid mitigation strategies in the built environment, including upper-room disinfection using GUV. In a nutshell, what was the research objective and primary findings?

Arnold: The purpose of the paper was to find out what is currently known in peer-reviewed scientific literature about the effectiveness and energy use of upper-room germicidal ultraviolet (GUV) systems to reduce the spread of COVID-19 relative to other approaches such as increased building ventilation and improved air filtration. We dug deep reviewing all the peer-reviewed scientific literature we could find on this topic. What we learned is that there is plenty of evidence that upper room GUV systems are highly effective in reducing the transmission of COVID-19. We also found evidence that GUV may do so at far lower energy use than increased outdoor air ventilation, but a more sophisticated analysis that considers the full range of applications, system types, and climates is needed to sufficiently characterize and quantify the effectiveness and energy benefits. We’ve since launched a new study to do this work and will publish a new paper of our findings later this year.

DiLouie: The paper evaluated various disinfection strategies with a focus on Covid transmission. In many people’s minds, the pandemic is “over.” Why study it? How much interest is there in the industry and among building owners for disinfection to offer healthier buildings?

Arnold: It’s true that we are beyond the worst impacts of the pandemic in that many fewer people are dying. What we are not beyond are the absenteeism impacts of COVID-19 that are being added to absenteeism impacts from other airborne infectious diseases such as influenza and RSV. Absenteeism continues to be significantly up from pre-pandemic levels. Airborne infectious diseases and the resulting absenteeism costs U.S. businesses over $200B annually in lost productivity, reduces student learning and achievement, and exacerbates public health and education inequities. The pandemic awakened people to the topic of indoor air quality (IAQ) and there is now more interest from building owners in improving building IAQ than ever before.

It is also important to consider the future. COVID-19 was not our last pandemic, and experts predict pandemics will occur with increasing frequency moving forward. Increasing our nation’s pandemic preparedness is a top priority of the White House. In fact, expanding the use of GUV is specific goal of the White House as described in the most recent progress report to implementing the American Pandemic Preparedness Plan.

DiLouie: GUV products are offered by lighting manufacturers, though it is questionable whether it is a lighting product unless integrated into luminaires. Who is responsible for these products in a construction or upgrade project, and where does the electrical contractor fit?

Arnold: Who is or will be responsible for the use of GUV in construction projects remains an open question. Currently, most GUV installations are proposed, designed, and installed by companies that specialize in indoor air quality and/or GUV solutions. The question is: will the lighting, electrical, or HVAC industries take on the GUV opportunity, or will it remain more of a specialized industry solution? Regardless of which industry(s) take it on, GUV products are effectively light fixtures and electrical contractors will be needed to install the products.

DiLouie: There are various approaches to using a portion of the electromagnetic spectrum to mitigate pathogens, from UV-C to UV-A and 405nm visible light. Why did the study focus on upper-room UV-C, and did it realize any interesting background findings on these other approaches?

Arnold: Generally, we focused on UV-C because it is much more efficacious for disinfection than UV-B, UV-A, and 405nm visible light. Additionally, you wouldn’t want to use UV-B because it penetrates human skin and eyes, resulting in it being potentially carcinogenic. UV-A and 405nm visible light can both be valuable tools in the right applications to deactivate viruses or bacteria, but it takes much more of it or a much longer period of time to do so, typically many hours rather than seconds. As such, they may be impractical solutions for reducing person-to-person airborne virus transmission in real-world applications compared to UV-C. They can be more effective for surface disinfection where they can be left on for long periods of time during the day and overnight.

DiLouie: Where do you see adoption of pathogenic mitigation strategies in the built environment going in the future?

Arnold: We are at the early stages of adoption of these strategies. The momentum is building, and the puzzle pieces needed to support more widespread deployment are coming together. I’m optimistic we’ll see increasing adoption over time, especially with the forthcoming ASHRAE 241P airborne pathogen mitigation standard that will codify new building design targets for these strategies.

DiLouie: What were the biggest advantages for upper-room GUV disinfection, as found or reported in the paper? What were the biggest disadvantages? What are the factors for a return on investment for upper-room GUV?

Arnold: The biggest advantage of upper-room GUV is that it is highly effective relative to other strategies such as increased outdoor air ventilation and offers an equivalent level of disinfection at a small fraction of the energy use. The biggest disadvantage is that GUV has safety implications if it is not designed and installed such that people are not exposed to UV above safety limits. The proper design and installation of GUV to ensure it is safe and effective is an essential issue that must be addressed for the technology adoption.

ROI calculations for GUV should consider installation, maintenance, and energy cost savings relative to alternatives such as increased building ventilation, improved filtration, or portable air cleaners. In the future it may be possible to include non-energy benefits such as reduced infections, reduced absenteeism, improved productivity, or improved student learning if these are sufficiently quantified.

DiLouie: Does the industry know enough to prove the value for upper-room GUV, and if not, what’s missing? Does the industry have sufficient products and expertise to deploy the technology?

Arnold: The value proposition for GUV is not yet sufficiently quantified. We know it works but we need to be able to quantify exactly how well it works compared to alternatives. First and foremost, we’ll need to be able to quantify its effectiveness and energy use in various applications. Our team is currently working to quantify these benefits in an office building application, and we hope to expand this work to other building types over time.

DiLouie: What opportunities does upper-room GUV present for electrical contractors? What should they take away from the research?

Arnold: At a minimum, electrical contractors will be needed to install this technology where it is permanently mounted. Beyond this, with sufficient training, there are opportunities for electrical contractors to recommend this technology to customers and offer a full scope of services including design, installation, commissioning, and maintenance.

DiLouie: How should electrical contractors engage customers about this technology?

Arnold: This technology has large potential benefits for customers, but it is essential that it is designed and installed to be safe and effective. Installations should provide enough UV on target mediums (air, surfaces) but must not expose people to too much UV that is over the safety limits established by the American Council of Governmental Industrial Hygienists (ACGIH). Installations must be carefully designed, and UV measurements must be taken post installation to verify safety limits are not exceeded. If recommending this to customers, electrical contractors should make sure they are trained or are working with a knowledgeable person to design and commission the system. The National Association of Lighting Management Companies (NALMCO) is developing a training and certification for GUV design, installation, and commissioning. I encourage contractors to learn more about this new training and certification.

DiLouie: If you could tell the entire electrical industry only one thing about upper-room GUV, what would it be?

Arnold: I encourage the industry to get or stay invested in this technology and get educated. There was a lot of hype during the pandemic about GUV, but the reality is we did not have the information needed to support the deployment. Some became disillusioned at the early lack of success, but there is much more to come, and we are still at the early stages. The benefits of this technology are massive for improved public health, reducing absenteeism, and increasing energy and carbon savings. I believe we are just getting started.

DiLouie: Is there anything else that you’d like to add about this topic?

Arnold: In May 2023, ASHRAE released a first draft of a new consensus-based, code enforceable standard for buildings to reduce airborne pathogen transmission called ASHRAE 241P. 241P sets and codifies higher targets for buildings than existing ventilation targets found in the ASHRAE 62.1 indoor air quality standard. Moreover, the draft 241P standard uses a technology-neutral, normalizing called Equivalent Outdoor Air (EOAi). EOAi can be calculated for, and the targets can be met using, a variety of technologies and approaches beyond ventilation including GUV. This new standard could be a gamechanger for GUV as we expect GUV will be one of the most effective, energy efficient, and economical methods to meet the new targets. We expect the 241P standard to be finalized later in 2023.

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Craig DiLouie


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