Frequently Asked Questions
At Biocare UV we understand that UV disinfection might be a new concept
to a lot of people; and so, we have put together this FAQ guide that will
hopefully answer any questions that you might have.
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You probably have some understanding of ultraviolet light; it is what we protect ourselves from when we apply sunscreen to avoid sunburn. UV light is invisible to the naked eye and exists between X-rays and visible light. UV light differs from other forms of light because of its wavelength.
UV light has a wavelength between 100 and 400 nanometres, which is shorter than that of any visible light. The term “ultraviolet” refers to the fact that this light has a shorter wavelength than violet light, which has the shortest wavelength of any colour light that is visible to the naked eye.
UV disinfection is the use of ultraviolet light to kill pathogens. While modern techniques have not always been in use, the effect of UV light on infectious microbes has been known and studied for more than 100 years.
UV disinfection is extremely effective. While different lamps perform differently, certain lamps disinfection can achieve 99.99% bacteria kill on surfaces in less than 4 seconds, which is 10x to 1000x better than existing treatments.
UV-C is the only wavelength known to be germicidal and utilises the shorter wavelength ultraviolet radiation than is harmful to pathogens. Only short wavelength UV-C produces the amount of energy necessary to kill pathogens.
When it comes to scientific use, different categories are used to distinguish one type of UV light from another. For these purposes, UV subtypes are Near, Middle and Far, with Near-UV matching up closest to UV-A, Mille-UV matching with UV-B, and Far-UV matching with UV-C in terms of wavelength, albeit the term FAR-UVC has come to be associated with a specific part of the UVC spectrum which offers the best balance between germicidal effect and human safety.
The wavelength determines what happens when the light comes into contact with human skin as well as dangerous pathogens.
Yes, UV light has been widely used for decades in different forms even within classrooms but is now predominantly used for disinfection in healthcare facilities, for food manufacturing, and in agricultural settings. Its shorter wavelength makes Far-UV the effective choice for disinfection.
A Far-UV light can cause the physical destruction of viruses, bacteria, moulds, and spores so that they will no longer cause harm. Furthermore, Far-UV light can cause this destruction quickly, without the use of potentially harmful solvents, making it an attractive choice an infection control tool as part of any pathogen prevention strategy.
As Far-UV light causes the physical destruction of cells, it is as effective against antibiotic resistant strains of bacteria known as “super germs” or “super bugs”.
Yes, but as with all UV-C solutions we need accurate inactivation (dose) response curves to determine the UV exposure (UV dose) required for the desired level of disinfection. Based on existing literature it is expected that Far-UV will be effective in inactivating SAR-CoV-2 given sufficient UV exposure. More recent studies have in fact demonstrated that SARS-COV-2 is susceptible to FAR UV as anticipated.
UV disinfection can be used for hard surfaces, liquids, and even air streams. In fact, UV light is one of the most popular non-chemical ways to disinfect water sources safely because it does not leave behind any chemical elements in the water.
Due to its versatility, disinfection with UV light is used in hospital, agricultural, pharmaceutical, and many other settings.
Far-UV is revolutionising this type of disinfection and opening the settings in which this type of disinfection can be used to include occupied spaces.
Ultraviolet light has been used for disinfection purposes for many years, and so we know that with proper precautions in place, UV is safe to use for disinfection. So long as those operating the disinfection devices are trained in the use of UV light and are themselves protected, the process is safe. It is also a good idea to take precautions to keep personnel who not protected out of rooms that are being disinfected with near UV light.
Far-UV disinfection can be performed with humans present as long as manufacturer’s instructions are followed to ensure proper use of the equipment and exposure below current threshold limit values.
Almost beyond argument if correctly filtered around the 222nm range, albeit research is ongoing to confirm this to be the case.
Far-UV is high-energy radiation which can directly damage the DNA of a pathogen through interaction with key organic molecules such as proteins. The bio-physical basis for the claims that Far-UV is “skin safe” is that radiation at or around 222nm is entirely absorbed within the outer, dead layers of the skin and does not reach the inner, live cells to affect their DNA. The same limits on penetration and thus safety have also been observed with the eye where FAR UV at 222nm does not penetrate the tear duct. UVC radiation at higher wavelengths does penetrate deeper into human skin and therefore is heavily regulated in terms of human exposure.
A large number of studies have now been published discussing acute and chronic exposure to Far-UV, most commonly using Kr-Cl excimer lamps. As of February 2021, over a dozen major studies have come to the same conclusion that filtered FAR UV at 222nm is safe and has produced no skin erythema or basal-layer DNA damage, even from doses many hundred times the current exposure limit values. These studies have investigated the effect of Far-UV radiation both on mice and human skin by measuring key chemical and physical changes known to indicate damage from UV-C exposure. It was found that these same damage indicators were NOT observed under Far-UV irradiation. Those reports are widely available, and we can share most of them on request.
Additionally, the exposure of humans to ultraviolet radiation is the subject of numerous regulations and standards worldwide: 2006/25/EC (Europe), ACGIH 2008 TLVs and BEIs (USA), and IEC 64271 (CB Scheme, Global); all employ an actinic UV hazard curve which lists UV-C as harmful, though at a weighting of 10-30% of that at the conventional UVGI wavelength of 254nm.
These standards therefore define an upper limit to how much Far-UV light the human body can be exposed to. This would then need to be compared to the dose that is required for the purpose for the Far-UV device was designed.
From a photochemical perspective from Kr-Cl sources, yes.
The Chapman cycle (Chapman, 1930) describes the counteractive processes of ozone formation and degradation from the interaction of light with molecular oxygen (O2) and ozone (O3). The rate of generation of ozone by Far-UV (known as the Herzberg continuum in atmospheric science) outweighs the rate of its degradation; the tipping point at which generation/degradation balance flips is ~242 – 243nm. (Andrew et al., 2003; Santos, Burini, and Wang, 2012), Far-UVC (200nm – 225nm) only generates ozone in the upper atmosphere, where path lengths are very long. In a normal laboratory/office space setting, ozone would not be generated because oxygen (O2) is a very weak absorber in the Far-UVC region.
BiocareUV products are always accompanied by ozone measurement and analysis to ensure any generation is within current regulatory limits (as set by, for example, UK WEL, OSHA, FDA).