Germicidal UV Lighting for Commercial and Industrial Applications
For over 100 years germicidal UV lighting been used as a disinfectant to kill viruses, mold and bacteria and has recently been recommended by the FDA as an effective method for eliminating SARS-COV-2 viruses which cause COVID-19. UV-C illuminating radiation operates at a wavelength of 200-280nm and when used at the preferred settings can effectively and efficiently disinfect up to 99.99% sanitation. Our GUV portable UV light towers deliver with high grade welded aluminum construction and industry leading UV-C components.
Offices, classrooms, hotels & hospitality, restaurants, dining facilities, production areas, manufacturing facilities, warehouses, hospitals, medical centers, dental offices, hair and nail salons, health clubs, gymnasiums, convention centers, exhibit halls, etc. Contact us for help on irradiation times and room sizes to determine the best fixture for your application.
What is germicidal UV, and what is UVGI?
Germicidal UV (GUV) refers to using ultraviolet radiant energy to inactivate bacteria, mold spores, fungi or viruses. When the process is applied in a given location, it has generally been referred to as ultraviolet germicidal irradiation (UVGI). Because of the public’s concern about ionizing radiation (e.g., X-rays and gamma rays), the term GUV avoids needless concerns about a link with that type of radiation. Another non-technical term is germicidal light, although “light” is technically only visible radiation.
Is all ultraviolet considered germicidal ultraviolet (GUV)?
No. Germicidal ultraviolet (GUV) – refers to short-wavelength ultraviolet “light” (radiant energy) that has been shown to kill bacteria and spores and to inactivate viruses. Wavelengths in the photo-biological ultraviolet spectral band known as the “UV-C,” from 200 to 280 nanometers (nm), have been shown to be the most effective for disinfection, although longer, less energetic UV can also disinfect if applied in much greater doses. UV-C wavelengths comprise photons (particles of light) that are the most energetic in the optical spectrum (comprising UV, visible, and infrared) and therefore are the most photochemically active.
Can UV-C kill viruses as well as bacteria?
Yes, UV-C kills living bacteria, but viruses are technically not living organisms; thus, we should correctly say “inactivate viruses.” Individual, energetic UV-C photons photochemically interact with the RNA and DNA molecules in a virus or bacterium to render these microbes non-infectious. This all happens on the microscopic level. Viruses are less than one micrometer (µm, one-millionth of a meter) in size, and bacteria are typically 0.5 to 5 µm.
Can UV-C effectively inactivate the SARS-CoV-2 virus, responsible for COVID-19?
Yes, if the virus is directly illuminated by UV-C at the effective dose level. UV-C can play an effective role with other methods of disinfection, but it is essential that individuals be protected to prevent UV hazards to the eyes and skin.
Does the ultraviolet in sunlight have a GUV effect?
Yes, particularly in the late spring and early summer when the sun is high in the sky and the UV index is high. At a UV Index of 10, the duration to achieve at least a three-log kill of bacteria (99.9% killed) is estimated as less than one hour.
How effective are portable UV towers for surface disinfection?
Portable UV towers and robots have been used to move around a room to disinfect surfaces with UV-C in all directions. The UV-C radiant energy is normally emitted by long, vertical mercury lamps or pulsed xenon lamps. Very intense emission can cover much of the room in a relatively short time. Further, by moving autonomously around the unoccupied work space it can expose surfaces that would not be easily reached by fixed GUV lamp installations. If good air movement is present, most air will be disinfected as well. Surfaces with thick buildup of residues may pre-absorb the UV-C photons before they reach the active virus or bacterium. As with all GUV systems, they should be considered as an effective adjunct to standard infection control cleaning guidance. These mobile units should be used after terminal cleaning.
What types of lamp sources are used for GUV disinfection?
Lamp technologies include continuously emitting low- and medium-pressure mercury lamps, as well as pulsed xenon arc lamps. Studies have shown that these technologies—continuously emitting or pulsed—are comparably effective for disinfection. Light emitting diodes (LEDs) and krypton-chlorine excimer lamps, which emit in narrow bands in the germicidal range (UV-C), are emerging technologies but have not been developed as an effective lamp source.
What is currently the most widely used lamp source of UV-C for GUV?
The most practical method of generating germicidal radiant energy is by passage of an electric discharge through a rare gas (usually argon) at low pressures (on the order of 130 to 400 pascals, or 1 to 3 torr) containing mercury vapor enclosed in a special glass tube with no coating that transmits short-wavelength UV. Hot-cathode germicidal lamps are identical in shape, electrical connection, operating power, and life to standard fluorescent lamps, both linear and compact types. Maintaining the transmission of the lamp over life is more difficult than for standard fluorescent lamps. Cold-cathode germicidal lamps are also available in various sizes, usually for shorter, smaller diameter lamps. Their operating characteristics are similar to those of hot-cathode lamps, but their starting mechanisms are different.
How do research scientists determine efficacy for killing or deactivation of different microorganisms and viruses?
The most fundamental concept in photobiology is the action spectrum (or relative response) for a given effect. Although there is a standardized germicidal action spectrum in the IES Handbook, it was based on inactivation of E. coli bacteria, and action spectra for spores, other bacteria, and different viruses can vary. This standardized action spectrum extends from 235 nm to 313 nm and peaks at approximately 265 nm. A wavelength of 254 nm has a relative efficacy of 0.85; by contrast, 313 nm in the UV-B has a relative efficacy of only 0.01.