Frequently Asked Questions
Ultraviolet light is composed of three wavelength ranges.
- UVC, from 100 nanometers (nm) to 280 nm.
- UVB, from 280 nm to 315 nm.
- UVA, from 315 nm to 400 nm
UVA and UVB are more commonly known. All UV light is emitted from the sun, but UVC does not reach the earth’s surface thanks to the ozone layer. UVC produced by artificial sources is the only way humans are exposed. And just like UVA/B from the sun (or a tanning bed), UVC has the potential to burn your skin.
The UV spectrum is one part of the electromagnetic (EM) spectrum. The EM spectrum includes radio waves, microwaves, infrared, visible light, Ultraviolet, X-rays and gamma rays. Radio waves have the lowest energy. Gamma waves have the highest. All waves of the electromagnetic spectrum emit radiation.
The words radiation and radiate commonly elicit images of nuclear meltdowns, bombs and people suffering horrific symptoms and/or death. But people forget they use radiation daily when they reheat food in the microwave, or listen to the radio. The difference between radiation from UVC and radiation from gamma rays (i.e. what is emitted from nuclear reactions) is significant.
UVC works by penetrating and damaging the DNA and RNA structures of microorganisms. But UVC does so most effectively and in the shortest amount of time at the 265 nm wavelength. UVC has been widely used in hospitals, schools and airports since the 1990’s.
Viruses and bacteria are simple organic structures that readily absorb UVC wavelengths. In seconds or less of UVC exposure, these pathogens suffer irreparable damage that leads to cell death and/or the ability to replicate, which also leads to death after rendering the organism harmless.
The CDC and ASHRAE have cited UVC as one technology that can “reduce the risk of dissemination of infectious aerosols in buildings and transportation environments.”
Historically, the most prominent use of germicidal UVC is in hospital settings. Prominent technology in hospitals since the 1990’s. Research has found that UVC reduces the transmission of common hospital “superbugs” such as resistant Staphylococcus aureus (MRSA), vancomycin-resistant enterococci (VRE), C. difficile and Acinetobacter. A CDC study in two hospitals found UVC reduced the total number of colony-forming units of any pathogen in a room by 91%.
Research has yet to find a microorganism that is immune to the destructive effects of UVC.
Just like viruses and bacteria, mold are simple organisms that readily absorb UVC and suffer irreparable damage. For most molds and mildews, UVC destroys in a matter of seconds, with the toughest – Stachybotrys – requiring minutes.
Katana products have been third party lab tested against molds such as B. cinerea (Bud Rot) and A. niger (black mold common to fruits and other plants). Successful kill rates of over 99% were shown with bud rot at less than one second and A. niger at 4 seconds.
Excessive, prolonged exposure is needed to damage plants or produce, making UVC a great disinfection option for both artificial and organic materials that need mold and mildew mitigation and prevention.
UVC is already a commonly applied technology for helping extend the shelf life of produce and juices. but research has also shown great promise for meats, wines, beer, and more. Not only does it destroy common food borne pathogens such as E. coli and Salmonella, it also destroys and slows the microflora on food products responsible for the rotting process without altering the quality of the product.
Currently, the food processing industry faces a limited range of commercially available equipment for disinfecting food products. Katana products are specifically designed to be used in areas that demand high levels of safety and sanitation. Their unique construction and IP67 rating makes them easily adaptable to a wide range of food processing equipment and allows for easy cleaning and sanitization between uses.
UVC exposure depends on time and intensity. A high intensity for a short period of time is equivocal to low intensity for a long period of time. No matter the intensity, the killing power decreases as the distance from the UVC source increases.
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LEDs and lamps are the two options readily available for UVC disinfection. But there are important differences to consider when comparing the two.
UVC’s germicidal eradication efficiency reaches peak activity around 265 nm. UVC LEDs turn on quickly and immediately emit true, consistent 265 nm UVC irradiation. Mercury-based lamps require a few minutes of warm-up time before they reach full output power. They are also limited to a less effective 254 nm wavelength, and only a fraction of the power provided to lamps is used to generate a 245 nm wavelength. The remaining input power to the mercury lamp generates other wavelengths of light that don’t contribute to germicidal eradication.
LED diodes can be arranged in a way to cover more specific areas and with greater intensity and can be generally converted from a flood light to a tiny ultra-high intensity focused beam using specialty lenses. This allows UVCs to make better use of UVC power with their pure and focused directional output. Mercury lamps are omnidirectional. This means they produce 360 degrees of light. This is a major inefficiency because at least half the light requires reflection in an attempt to reach the desired surface – meaning wasted energy and intensity.
LEDs offer longer lifespan over traditional mercury-based lamps and can be used in applications that require immediate disinfection with instant on/off capabilities. Lamps and their high voltage ballasts are not designed for this and rapidly degrade in both performance and lifespan.
LEDs offer zero maintenance and hassle (do not require bulb replacement for the life of the product). They also allow for great diversity across various applications in their form factor, allowing engineers and designers to develop unique and durable solutions that are not possible with fixed size glass-based mercury lamps. A very clear benefit of LEDs is that all LEDs can be powered from a simple battery source which allows them to be very portable. Mercury lamps high voltage ballasts typically require the use of and proximity of a wall power outlet.
Katana LEDs are packaged in a way that allows the devices to be easily rinsed and sanitized between uses (removing the risk of cross-contamination from the very tool you are using to decontaminate other things). Lamps require bulb changes, are limited in the places and ways they can be used (cannot be used in damp locations or where could be bumped/broken), and cannot be easily rinsed/cleaned (they require gentle wiping down with alcohol swabs every 3-6 months – or more if used in dirty areas – avoiding human touch as the oils on your hands can reduce UVC output).
LEDs are safe. Not only through directional lighting, but because of durability and lack of hazardous materials. Lamps are made of easily breakable soda-lime glass or quartz, and contain toxic mercury or xenon. If a bulb is broken, people, planet, and profits are at risk.
UVC LED technology has advanced rapidly in recent years. Early development of LEDs for UVC saw low life span and efficiency, primarily due to issues with heat. Not to mention they were extravagantly expensive. But in the past five years especially, technology has overcome these barriers. (A similar journey we saw with household LED bulbs.) It is an exciting time in UVC LED technology and what it can do!
Direct exposure of UVC to skin and eyes can cause painful injuries and burns, especially at shorter wavelengths. These risks are easily avoided through the use of protective eyewear and clothing or applying UVC in unoccupied spaces. It is important to understand how to use UVC products safely and in a manner that is effective.
Wavelength corresponds directly to the amount of time needed for exposure. The shorter the wavelength, the higher the frequency. Higher frequency means it emits greater power. Greater power means the exposure time required to kill microorganisms is less. Home use products generally emit longer wavelengths and lower frequency. This means longer exposure time for surfaces and items is needed (rendering most home use handheld devices impractical). Simply waving a home use wand over a surface is likely doing very little for bacteria and virus elimination. The longer wavelengths also create ozone. Ozone can damage the lungs and irritate the eyes and other organs.
Katana UVC products emit true 265 nm UVC light through directional UVC LED light technology. All UVC is a line of site disinfection (meaning the UVC light has to touch a surface in order to sanitize). With a directional light source, you can take comfort in greater safety during use. And when used correctly, the Katana products provide high absorbency, powerful intensity, and low risk tools for preventing and mitigating organic contaminants such as molds, mildews, bacteria and viruses.
UVC can have subtle long term effects on certain materials. For example, if a plastic generally has a lifespan of ten years, but is continuously exposed to UVC, it will likely need to be replaced in 9 years. Plants will only suffer damage if exposed to regular, many hours long exposures. Dies and colors can also be affected, fading from prolonged continuous exposure.
The small doses of UVC needed to kill microorganisms will not affect most materials, even with repeated applications.
X-ray and gamma radiation are ionizing. They penetrate deep into and through the body (and other substances). UVC (and other electromagnetic radiation) is non-ionizing. This means it has low penetration depth. It only affects the superficial layers of skin, mucous membranes and eye tissues. So unless you are an exceptional exfoliator, dead skin on the human body is sufficient to absorb UVC radiation almost completely at low doses. UVC also has higher energy than UVA and UVB, meaning it is more readily absorbed by organic materials. This is what allows it to quickly deactivate and kill simple microorganisms that don’t have layers upon layers of cells protecting them like people do.
Both ionizing and non-ionizing radiation can cause cancers depending on dosing and regularity of exposure. Gamma radiation is especially harmful because it can linger. (Think Chernobyl where it will take at least 20,000 years for the radiation to disperse.) However, X-ray and UVC radiation are only present as long as there is an emitting source. Once that source is turned off, the radiation is no longer present. So unlike chemicals (and nuclear reactions), UVC does not leave behind any harmful residue.
No, Katana UVC products do not produce Ozone. Katana’s UVC LEDs emit a true 265 nm wavelength. UV wavelengths between 100 nm and 240 nm – with peak ozone production occurring at 185 nm – produce ozone. In fact, UV wavelengths 250 nm and above can destroy ozone residuals.
The application of Katana products holds vast potential. With handheld and mounted options, you can layer your approach to sanitizing a wide range of surfaces and equipment. Keep medical and food environments clean, extend the shelf-life of food products, and protect plants, employees, and much more.
The Katana product line is IP67 rated. This means it is waterproof as well as protected for fine dusts and other particulates. This makes them simple to clean. They can be sprayed, wiped or dunked in cleaning solutions, eliminating cross contamination risk and saving time.
We are exposed to other parts of the UV spectrum everytime we are outdoors. Generally, damage does not occur unless excessive exposure is received. All UV light will damage collagen fibers and accelerate skin aging. With prolonged exposure it can burn and increase chances for cancer. This is why sunscreen exists and is recommended. However, all UV light is not the same. Both UVA and UVB can penetrate skin into its deeper layer, the dermis. Whereas UVC barely penetrates past the stratum corneum – our most outer layer of skin. Just like UVA and UVB, UVC can cause superficial damage with long exposures. But unlike UVA/B, it has not yet been associated with long-term tissue effects, likely due to its inability to penetrate deeper layers of skin.
That being said, UVC can still cause aging, damage, and discomfort to your skin and eye tissues. Because of UVC’s higher intensity, damage can occur faster than with UVA/B, and protective measures should include UV blocking protective eyewear, protective face masks depending on the situation (such as activities like welding – where UVC flash burns are common if protection is not used) and clothing such as a long sleeve shirt, long pants, and closed shoes.