Originally featured in the September / October 2022 Issue of Lighting Management & Maintenance, the magazine of the International Association of Lighting Management Companies, NALMCO®
Written by George McIntyre Regional Renovation Manager, Acuity Brands Lighting and Controls and Mary Hollenbaugh Architectural Sales Manager, Acuity Brands Lighting and Controls
One of many issues the COVID-19 pandemic has underscored is the necessity for public and private spaces to be clean and sanitary to help contain the spread of viruses and germs (pathogens). Among several disinfection practices gaining new attention is ultraviolet light (UV) disinfection technology (AKA germicidal UV or GUV), which is an effective engineered solution that can be added to other methods of cleaning and treatment. Despite the known capabilities of various UV lighting disinfection solutions to inactivate pathogens, many customers still have questions and may even be misinformed about UV lighting technology. Below are answers to some questions that can arise frequently when presenting UV disinfection lighting solutions to customers.
1. What is Germicidal Ultraviolet Light (GUV)?
Certain wavelengths of ultraviolet light have been known for some time to have the ability to inactivate bacteria, viruses, and fungi. Newer research findings have shown that UVC wavelengths (under 280nm) are particularly effective wavelengths for inactivating viruses and bacteria. Because UVC (200-280nm) has the strongest “germicidal” properties within the full UV spectrum, most GUV light technologies utilize UVC light sources. As a result, GUV light technologies incorporating UVC are currently used in a number of air, water, and surface disinfection products and systems. Interestingly, the earth’s atmosphere removes the UVC band from solar radiation before it reaches the earth’s surface, so all UVC light must be generated from electric light sources.
2. How does UVC work as a disinfection technology?
Studies have demonstrated that, in a laboratory setting, UVC (200-280) has inactivated known viruses and other pathogens, including SARS-CoV-2 (which gave rise to COVID-19), on surfaces and in the air. The energy generated in this UVC wavelength range breaks down the structures inside the pathogens preventing them from replicating, thus rendering these pathogens harmless. The germicidal effectiveness of UVC is dependent upon a variety of factors including, but not limited to, the amount of time the pathogen is exposed to the UVC light and the intensity of UVC light exposure. With air treatment, air circulation in the space is an important consideration, so that any pathogens in the air are dosed by the UV. On the other hand, for surface treatment to be effective, it is important that the pathogen be exposed to the UVC light. Pathogens in areas that fall in the shadow of the UVC are not inactivated, which is why UVC light disinfection technology should be used in conjunction with chemical cleaning of surfaces.
3. In general, how can UVC products be installed and used safely? Can UVC lighting be present and dispensed with people in the space?
UVC products can be used and installed safely in an indoor space if the appropriate dosage is determined and delivered, and all safety precautions are addressed prior to and during installation. The necessary safety precautions with respect to application of UV products are determined by the technology involved, and the UVC products selected must be differentiated according to whether they are designed with direct, indirect, or mixed UV light. If fixtures utilizing the UVC wavelength are improperly used or installed, UVC light may pose a safety and health hazard to the eyes and skin. UVC can cause eye or skin injury with overexposure, but the primary effects are temporary. Shorter wavelengths represented by 222nm filtered far-UVC are the least penetrating of all UVC wavelengths. 222nm penetrates only the outermost layer of the skin (dead skin cells) or the cornea, providing a natural protection for the living cells. According to ANSI/IES RP-44-21 Recommended Practice for Ultraviolet Germicidal Irradiation (UVGI), the risk of skin cancer is relatively insignificant, and there are no known long-term consequences for eyes from an accidental overexposure to UVC. Results from laboratory testing and clinical studies have shown that the filtered 222nm far-UVC light in particular is effective against a wide range of bacterial and viral pathogens at doses that still fall within current exposure guidelines for human occupancy, as established by the American Conference of Governmental Industrial Hygienists (ACGIH®). The ability to make use of doses at these levels means that lighting products using the filtered 222nm far-UV light can be safely used in occupied spaces.
4. Is UV lighting complicated to install and/or difficult to maintain?
Installation of UVC equipment from a reputable manufacturer should be straightforward and no more complex than installing a lighting system. Before making an investment in a UV system, the purchaser will want to review installation and operation manuals carefully to anticipate maintenance requirements over the life of the system. Additionally, the purchaser should consider the operating cost (efficiency) of the system over its life. Many UVC lamps are field serviceable. Warranties will vary by manufacturer, and expected life cycle relies on multiple factors, such as dosage amount and frequency and length of dosing in a space. For example, the Care222® module from Ushio used in many Acuity Brands UVC lighting solutions has a rated lifetime of 3,000 hours, which, depending on actual dosing times, can equate to an expected operating lifetime of approximately 5 years or more.
5. If Covid-19 infections continue to subside, why would my customers still need or desire UVC disinfection technology?
UVC disinfection products, when installed and used correctly, can help manage overall hygiene in a space, as most are effective in killing or inactivating many strains of bacteria, viruses, and fungi that can give rise to the flu, common cold, and other maladies. Minimizing the potential for exposure to these types of pathogens in the built environment can help positively impact attendance (reduce absenteeism at school, work, etc. due to illness) and other key productivity factors. Because UVC products are a chemicalfree method of providing disinfection capabilities, UVC can help with sustainability goals such as reducing the amount and the frequency of applying cleaning chemicals, which often have toxic ingredients and can have a negative impact on indoor air quality and the environment.
6. How is UV disinfection technology different or unique from other forms of disinfection? Why not just upgrade the HVAC system or certain cleaning methods?
UVC lighting solutions do not necessarily need to be installed in every space to provide benefit. Customers should invest wisely and focus on the areas where a lot of people gather or there are high-touch surfaces. Especially in these types of spaces, UVC products can help disinfect both air and surfaces on a preprogrammed schedule. Relying only on traditional mechanical and/or chemical cleaning leaves room for human error and can be time consuming and sporadic. HVAC systems alone can clean the air flowing into a space, but not immediately address the existing air in the room where occupants are present. Additionally, the HVAC system does not address surfaces such as desks, tables, chairs, counters, toilet seats, and sinks, which are easily contaminated.
7. How do I determine/recommend the best UVC lighting product/solution for my customer?
Multiple factors go into helping to determine a UVC solution for a space, including how often a space is occupied and for what purposes, the size of the space and ceiling height, the amount of human interaction, the number and type of surfaces, the pathogens to be targeted, budget, and so forth. Selecting a reliable manufacturer with expertise in UVC technology can greatly assist in the evaluation process and help customize a solution for your customer. Because lighting is necessary for occupied spaces, integrating UVC technology into lighting systems 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 as a layer of functionality to necessary illumination. The UVC technology, while generally operating independently from the lighting, may use the luminaire’s intelligent control capabilities, and may be connected to an overall building management system. Additionally, integrating UV with luminaires creates the opportunity to provide local treatment within the space, where the pathogens are being introduced into the environment. Software tools, such as Visual® Lighting software by Acuity Brands, provide the ability to perform a detailed analysis prior to installing a system. Much like performing lighting calculations, the software models and evaluates the intended application space and the amount of irradiance from UVC light disinfection products, providing designers, installers, and customers in-depth understanding of how the UVC light disinfection system may reduce pathogens based on pathogen research data.
8. How is this technology controlled and metered? Does it utilize occupancy sensors or some other controls technology?
Controls are an integral part of a UVC system design. Depending on the product and technology type, these controls may detect occupancy or meter the dosage size and frequency in a space or monitor that the system is operating correctly. The controls should be aligned with the design parameters and calculations customized for the space to deliver the specified dosage at the appropriate times. Always consult with specific products specifications on recommended controls or system integration methods.
9. Is there an ROI for this technology?
To help determine an ROI, the first task is to decide what "return" is desired. For example, is the objective to decrease the number or frequency of absentee students and teachers? Make a space safer for customers? Help protect employees that work in close proximity? A school may focus its ROI on school attendance for both students and staff. In the past two years, the pandemic has kept school staff and students at home, impacting the learning environment, test scores, social interaction, and the general mindset of students. Lowered transmission rates of various pathogens could mean more students and staff attending in-person throughout the year (due to less illness) and even less need for substitute teachers. A UV solution’s ROI can be easily achieved when businesses add a layer of protection that can help minimize the potential for staff absences that may result from exposure to many types of pathogens. This same layer of protection can also help reduce potential exposure for customers. For the retail and hospitality sectors, this is a double win. Similarly, in manufacturing facilities, workers often need to work in close proximity. By installing a UV solution to reduce exposure to pathogens, production staff can likely stay on the job and maintain production output. Maintaining a steady output can result in less additional overtime pay later to catch up on backlogs.
UVC lighting disinfection technology can safely offer an additional layer of protection by treating surfaces and air 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, manufacturing, retail, health clubs, and healthcare settings. Again, please refer to available reference materials for more information and details.