Occupants can be Present
Filtered 222nm far-UVC light can be used while people are present in the space
Reduction of Pathogenic1 Bioburden
Inactivates viruses1 and bacteria1
Continual air and surface disinfection technology
Care222® filtered 222nm far-UVC light continual air & surface disinfection technology is designed to meet today’s American Conference of Governmental Industrial Hygienists (ACGIH®) safety guidelines for exposure to a filtered 222nm far-UVC light source when used within appropriate parameters.
Filtered 222nm far-UVC light technology can be used wherever people gather and interact. The ideal application is for this continual air and surface disinfection technology is when the goal is to inactivate pathogens1 as soon as they enter the space.
The proteins on the top layers of the cornea of our eyes absorb 222nm far-UVC. When following safety guidelines, the 222nm wavelength does not penetrate these tissues to depths associated with cataracts, photokeratitis, and other eye conditions. In contrast, possible acute and chronic damage to eyes may result from the more generally employed 254nm UV wavelength used in many germicidal lamps. In addition, although lamps in the 405-430nm wavelength range can also be used in occupied spaces, they are not as effective against viruses1 as lamps with lower-range UVC wavelengths.
In addition to not affecting the eyes, 222nm far-UVC is also does not negatively affect the skin, when used following safety guidelines. Filtered 222nm does not affect living skin cells because it does not penetrate beyond dead skin cells of the stratum corneum. In contrast, possible acute and chronic damage to skin may result from the more generally employed 254nm UV wavelength used in many germicidal lamps.
The filtered 222nm technology utilizes an excimer lamp that employs a specially designed short pass filter to remove harmful UV wavelengths, resulting in a narrow band of UV centered at 222nm. Excimer lamps are arc discharge light sources with a special chamber filled with noble gas, completely mercury-free and without electrodes. Acuity Brands luminaires with Care222® far-UVC disinfection technology employ proprietary integrated controls to modulate pulses of the 222nm far-UVC to provide an appropriate dose that allows operation within the ACGIH safety guidelines.
Acuity Brands followings the dosing guidelines as outlined by the ACGIH and adopted by the International Electrotechnical Commission (IEC) in IEC 62471, Photobiological Safety Of Lamps And Lamp Systems. The level of reduction of pathogens1 will depend upon the dose delivered, measured in mJ/cm2, which is a measure of radiant energy per unit area. Since the dose is an energy quantity, effectiveness will depend on the design of each application based on irradiation and time of exposure. At 222nm, relatively small doses over time are needed to inactivate bacteria1 and viruses1 to reduce the pathogenic bioburden on the surface that is in contact with the UV light. Acuity Brands luminaires with Care222® pulse the 222nm at a dose for continual operation in the occupied space to meet the ACGIH® 8-hour Threshold Limit Value (TLV).
1. Calculate planar irradiance in μW/cm2 at locations where pathogen1 reduction is desired and where people will interact
2. Convert planar irradiance to Dose in mJ/cm2
3. Confirm design is providing sufficient quantities of the filtered 222nm far-UVC based on expected performance to achieve targeted pathogen reduction within safety guidelines
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How does filtered 222nm far-UVC light inactivate pathogens1?
The 222nm far-UVC light penetrates the outer layers of the pathogen structure to render it harmless through disrupting the nucleic acids (DNA and RNA), resulting in the disruption of vital functions, stopping the ability of the pathogen to replicate.
Why can filtered 222nm far-UVC light be used in occupied spaces?
Because 222nm far-UVC light can be effective against wide range of bacterial and viral pathogens1 (up to 99.9% in 24 hours for studied pathogens) in relatively low doses, it can be used in occupied spaces and still fall within current safety guidelines for human occupancy, as established by the American Conference of Governmental Industrial Hygienists (ACGIH®).
Do all UV wavelengths have the same safety issues?
No. The 222nm wavelength can be eye and skin safe at useable power levels, allowing the space to remain occupied during use. 254 and 274nm wavelengths are not eye or skin safe; requiring that the space be evacuated during use, used in upper room germicidal UV applications or in concealed applications.
*All references to “disinfection” are referring generally to reduction of bioburden and are not intended to refer to any specific definition of the term as may be used for other purposes by the U.S. Food and Drug Administration or the U.S. Environmental Protection Agency. The disinfection technology as incorporated in Acuity Brands products is not intended for use in the cure, mitigation or prevention of disease and is not certified or approved for use as or for the disinfection of medical devices by the FDA. Bioburden reduction is a function of fixture run time, distance to the UV light source, air flow, room size, shadow areas and/or other factors, and the level of reduction will vary within a specific space.
¹ Refer to product specification sheets at acuitybrands.com/UV-Products for efficacy claims and claim substantiation regarding specific products and pathogens.
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