THE FIRST OF ITS KIND NALMCO Leads the Way With Industry-First GUV Certifications
A typical UV-C lamp has three components: the mount, the reflector, and the baffle. The mount usually contains the power supply and electrical components and is attached to the wall or ceiling. The reflector helps to make certain that the maximum amount of light from the source is directed to the areas of concern. The baffle or louvers block unsafe stray light that may find its way into the occupied zone of a room.
By Parker Allen with Dr. Katja Auer and Bill Palmer
SAFETY
The concept of using germicidal ultraviolet light for infection prevention is not a new one; it dates back to the late 19th century, when it was discovered that microorganisms are susceptible to various wavelengths of UV light. Recently, the resurgence of diseases transmitted through the air, such as tuberculosis and COVID, has rekindled interest in germicidal UV (GUV). LM&M // JANUARY 2024 // THE FIRST OF ITS KIND
Lamps emitting ultraviolet light at 254 nm are most commonly used as upper room disinfectants. Additionally, LEDs emitting 265 nm have recently been applied to upper room. Excimer lamps emitting 222 nm can be used in down lights, as they are considered safe for human exposure due to their low intensity as compared to 254 nm.
Given this renewed public interest, many clients, in a wide variety of settings, are asking about adding germicidal UV fixtures in their buildings. First, a quick discussion of GUV to help you familiarize yourself with the technology.
ULTRAVIOLET LIGHT
Ultraviolet light is commonly associated with sunburn and skin cancer. The wavelengths responsible for these hazardous health outcomes, however, fall in the UV-A and UV-B portions of the spectrum. According to Recommended Practice: Risk Group Classification And Minimization Of Photobiological Hazards From Ultraviolet Lamps And Lamp Systems (ANSI/IES RP 27.1-22), "There is no evidence at this time of carcinogenic risk in humans from UV-C exposure.”1 This document was published in 2022 and is a globally recognized ANSI standard. The risk associated with UV-C (254 nm) is for skin and eye irritation and is well defined. Follow the guidelines set forth in ANSI/CAN/UL 8802-2023, Standard for Ultraviolet (UV) Germicidal Equipment and Systems to limit these risks.
Ultraviolet light occupies the portion of the electromagnetic spectrum just above visible light in terms of energy. Ranging from 100 to 400 nm, ultraviolet light is categorized into different ranges based on penetration depth into living tissue. For germicidal UV applications, the UV-C portion, spanning 200 to 280 nm, is the portion of interest.
Wavelengths in the UV-C portion of the spectrum have more germicidal activity and pose significantly less risk to human health. Image courtesy of Bill Palmer. The ultraviolet portion of the electromagnetic spectrum. Image courtesy of Bill Palmer. The mechanism of disinfection using ultraviolet light involves damaging the DNA, RNA, and proteins within microorganisms and viruses, rendering them incapable of replication. The effectiveness of disinfection depends on the intensity of UV, distance from the source, and duration of exposure. While concepts like microbe sensitivity, wavelength efficacy, and optimal dosing practices continue to evolve, the fundamental aspects of these processes are reasonably well understood.
UV-C SOURCES AND APPLICATIONS Various types of UV-C sources exist, each emitting light at different wavelengths. Historically, low-pressure mercury lamps have been the most common, effective and affordable. Other options include excimer lamps, pulsed xenon lamps, and LEDs, all capable of producing UV-C light.
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BENEFITS AND DRAWBACKS Chemical disinfection methods are widely used but expensive, and chemical disinfectants often pose health hazards. Given lighting’s ubiquity in our spaces, using light for disinfection is a desirable alternative to chemical methods. UV-C is often less expensive to install and is more impactful than other physical disinfection methods, such as ventilation and filtration. Furthermore, upper-room GUV takes up no floor space, doesn’t generate any noise, and uses MUCH less energy than in-room filtration devices or ventilation. It’s easy to install and doesn’t cause disruption to services like you would see if installing a new ventilation system. The biggest road block to widespread adoption of GUV has been a lack of familiarity and experience in applying the technology. If only there were some sort of GUV certification program…
