I had the pleasure of interviewing Gary Trott, Vice President – Technology Commercialization, Acuity Brands Lighting, about filtered far UV-C disinfection for an article I wrote for the December issue of ELECTRICAL CONTRACTOR. Acuity has entered a strategic partnership deal with Ushio to incorporate filtered far UV-C modules into select general lighting luminaires, which will be available in late 2020. Transcript follows.
DiLouie: What kinds of organisms is 222nm filtered far-UVC effective against and in what form (aerosol, droplets, fomites)?
Trott: 222nm far-UVC is effective against a wide range of bacterial and viral pathogens (99.9% reduction in pathogenic bioburden in 24 hours for studied pathogens). It penetrates the outer layers of the structure of a pathogen to render it harmless. With bacteria, DNA is disrupted. With viruses, RNA is disrupted. In both cases, vital functions are disrupted, stopping the ability of the pathogen to replicate.
As a side note, effectiveness of 222nm filtered far-UVC against SARS-CoV-2, the cause of COVID-19, is currently under study at Columbia University. Because tests of the 222nm disinfection technology against this virus have not been completed, it is not possible to say with certainty that the 222nm wavelength will inactivate this pathogen. However, the 222nm filtered far-UVC disinfection technology has been shown in another study by Columbia University, recently published by Scientific Reports, to have the ability to inactivate seasonal coronaviruses that have a viral structure similar to SARS-CoV-2.
Editor’s note: Since this interview, a research study was published that indicated efficacy of far-UVC against SARS-CoV-2 in a laboratory (in vitro) experiment.
DiLouie: Why are luminaires a suitable or even ideal platform for introducing 222nm far-UVC-based disinfection into a space?
Trott: Because lighting is necessary for occupied spaces, integrating 222nm filtered far-UVC delivery capabilities into lighting systems in spaces where reduction of infectious pathogens is desired makes practical sense. Using luminaires as a delivery system allows facilities to take advantage of locations where power is already distributed and can be seamlessly integrated into an architectural lighting design. This enables the disinfection technology to be added to necessary illumination as an additional layer of functionality that can take advantage of the luminaire’s intelligent lighting control capabilities. The disinfection technology layer will operate autonomously and independently from the illumination functions to provide protection against infectious pathogens throughout the day. Acuity Brands will be incorporating the Care222® filtered far-UVC disinfection modules from Ushio America in novel and familiar luminaires from its lighting brands such as Mark Architectural Lighting™, Lithonia Lighting®, Healthcare Lighting®, and others.
DiLouie: Is 222nm filtered far-UVC enough or is it recommended with a multibarrier (regular cleaning, social distancing) approach?
Trott: The 222nm far-UVC technology, when filtered correctly, can contribute significantly toward reducing the pathogenic bioburden on indoor surfaces in occupied and unoccupied spaces when properly designed, installed, and applied. At the same time, this technology’s effectiveness requires surfaces to be exposed to the 222nm filtered far-UVC, and it will not be effective at reducing the pathogenic bioburden on surfaces hidden from direct view such as the underside of a desk or table or surfaces that are covered with dust or dirt. The best practices for disinfecting a space and protecting occupants from exposure to infectious pathogens moving forward will continue to include using a comprehensive approach using multiple, proven tactics.
DiLouie: What are the benefits of installing luminaires featuring 222nm Filtered far-UVC capability?
Trott: As previously mentioned, integrating 222nm filtered far-UVC delivery capabilities into lighting systems where reduction of infectious pathogens is desired makes practical sense. Using luminaires as a delivery system allows facilities to take advantage of locations where power is already distributed. This enables the disinfection technology to be added to necessary illumination as an additional layer of functionality that can take advantage of the luminaire’s intelligent lighting control capabilities. The disinfection technology layer will operate autonomously and independently from the illumination functions to kill pathogens throughout the day. The Care222 technology operates intelligently to deliver a dose of UV within established safety guidelines at a pre-programmed rate throughout the day. Integral to the system are mechanisms to indicate proper operation, giving facilities and occupants assurance that the UV disinfection system is maintaining its effectiveness.
DiLouie: What are the applications for 222nm Filtered far-UVC technology?
Trott: Any inanimate surface that can be directly irradiated can benefit from the pathogenic bioburden reduction provided by 222nm filtered far-UVC light. When used in luminaires deployed in general lighting systems, the technology will offer an additional barrier against infectious pathogens on surfaces in all types of high-interaction applications, including offices, conference rooms, meeting spaces, classrooms, public restrooms, restaurants/hospitality, performing arts and sports events, public transit, retail, health clubs, and certain healthcare settings.
DiLouie: What are the applications for 222nm filtered far-UVC technology within these spaces? Is it primarily surface-focused or will it also be used for upper-room disinfection?
Trott: In general, UVC wavelengths can clean both air and surfaces within limits. In order to be effective, the UV light must strike the pathogens for a sufficient length of time at the requisite power density to deliver the lethal dose necessary to inactivate the pathogens. On a surface, pathogens are stationary, and the necessary dose can be more readily predicted for a given application. However, airborne pathogens float in the air and may move outside of the UV beam. Only if an airborne pathogen remains in the beam for a sufficient timeframe can it be inactivated. 222nm filtered far-UVC is intended for direct view applications where occupants can be present in the room and it is not the best choice for applications where occupancy is not required. Another option to address airborne pathogens is to include an air handling unit that incorporates UVC. Because the UVC source is occluded, technologies that are not considered safe for direct view applications (namely 254nm UV) can be used, enabling lethal dosages of UV to be delivered quickly and efficiently to pathogens that are drawn into the air handling equipment. 254nm technology is also viable for upper-room air disinfection where there is no direct view by occupants of the UV light.
DiLouie: Please walk us through a typical space and how the visible light and 222-UV module would work together. How is the separate lamping controlled?
Trott: For Acuity Brands, the patented Care222 module from Ushio America that delivers filtered, 222nm far-UVC light will be specially engineered, and UL tested for multiple luminaire families. The luminaire layout and number of modules required will depend on the specification and related calculations. The luminaires with the module installed will pulse the 222nm light — using our luminaire’s intelligent control capabilities — using ongoing dosing for occupied spaces based on current safety guidelines for human occupancy, as established by the American Conference of governmental Industrial Hygienists (ACGIH®)
In general, for a UV disinfection system to be effective, several factors come into play: determining the proper UV light wavelength (not all UV light is equal); the pathogens you want to target; where reduction of disease causing pathogens is desired; and where people will be in a space. And then there a series of steps to follow in designing an effective UV disinfection system, much like the approach we take for designing a lighting system. The added step here is to understand the potential level of exposure (the dose) of UV and relating that dose to expected pathogen reduction and adherence to safety guidelines for a given UV wavelength technology.
DiLouie: What do electrical contractors need to know about these luminaires to recommend, safely install, and assist with maintenance?
Trott: Acuity Brands luminaires featuring our filtered far-UVC disinfection technology will come factory calibrated per the calculations performed at the time of specification using our Visual® software. The luminaires should be then installed in the space per the design with all of the appropriate parameters verified in the field.
DiLouie: We are all hoping to be living in a post-COVID world soon. Do you believe building owners will adopt at least a somewhat permanent disinfection stance in their buildings?
Trott: Yes, we believe disinfection protocols will become more standard practice for building owners. COVID-19, as well as those viruses and bacteria that give rise to flus, the common cold and other ailments, will continue to be a part of our everyday working and living environments, and occupants will want and, in some cases, insist that disinfection best practices are in place. And this falls in line with the trend that was already emerging where occupants and tenants alike have been asking for more individual control over lighting, HVAC, and other building systems to enhance comfort and improve efficiencies.
DiLouie: If you could tell all electrical contractors one thing about 222-UV disinfection, what would it be?
Trott: Study up on this technology as much as possible through training modules and other sources, ask questions and partner with credible, knowledgeable manufacturing partners and design professionals who can provide technical assistance when working with your customers.
