UV LIGHTING GUIDE
Lighting Guide
1 UV LIGHTING GUIDE contents
About UV U Lighting 3 Guide Types of U 5 D Application of 7 U D Various Sources of U ED 10 Benefits of 12 U ED T U 14 D D U 16 L 17 U D
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About UV Light
ltraviolet ray refers to the far end of the to 400 nm), UVB (280 nm to 315 nm), and UVC (100 electromagnetic spectrum, which is invisible to nm to 280 nm). UV radiation possesses sufficient Uthe naked eye. It has a shorter wavelength (100- energy levels to bring about chemical changes by 400 nm) and higher frequency as compared to the breaking chemical bonds when it comes in contact visible violet light. The term wavelength can be defined with certain elements. UV radiation with wavelength as the distance between two successive crests or below 200 nm can break a molecule of oxygen (O2) troughs of a wave (which may be an electromagnetic into its constituent atoms, which when comes in wave, sound wave, or any other wave). Crest is the contact with another molecule of oxygen (O2) gives highest point of the wave while trough is the lowest. The birth to ozone (O3). Ultraviolet radiation below 300 nm wavelength is measured in units of length. The energy has germicidal properties as it could tamper with the associated with an electromagnetic wave is inversely genetic materials (DNA or RNA) of bacteria and virus, proportional to its wavelength. In other words, shorter thus rendering them ineffective. Although ultraviolet the wavelength, higher the energy. radiation between the wavelength below 315 nm can cause sunburns, it helps in generating vitamin D when UV ray can be categorized into 3 types according to its absorbed by the skin. wavelengths or energy levels, which are - UVA (315 nm
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Infrared Visible Light Ultraviolet X-Rays required to consider the various properties of matter that UV ray may interact with if they are to be a part of UVA UV UVC a stable UV radiation system. B The origin of UV radiation could be traced back to plasma sources which includes the sun and plasmas 780 400 315 280 100 in electric (or arc) discharge lamps. The radiation Wavelength (NM) generating from plasma sources isn’t limited to UV Electromagnetic Spectrum rays only. It produces a wide spectrum of wavelength which includes infrared radiation and visible light. The range of wavelengths produced by an arc lamp could The chemical effects caused by UV radiation depends be adjusted according to the requirement by adding upon the wavelength of the radiation and chemical certain impurities. By adding mercury, iron, gallium or composition of the matter it is interacting with. This other metals to the plasma in the arc, it is possible to interaction can vary widely depending upon the various generate different wavelengths of UV rays. properties of matter (transparency, reflectivity, and chemical stability). For example, ordinary glass is In a recent development, it has been found that opaque to UV radiation shorter than 350 nm, whereas semiconductor diodes could be used to generate high purity quartz is opaque to UV radiation shorter than UV radiation. Semiconductor diodes sources of UV 200 nm. Similarly, polished surfaces that are a good radiation are very different from traditional UV arc reflector of visible light may not be a good reflector of lamp sources. The next section will talk about the UV light as well. Systems that produce UV radiation are effectiveness of UV light as a disinfectant.
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Types of UV Light & their Disinfection Properties
s mentioned in the previous section, UV light ozone layer present in the earth’s atmosphere. has germicidal properties though it would be wrong to state that all kinds of UV rays could Studies have shown that UVC at 254 nm could A incapacitate all food borne pathogens, moulds, and be used effectively as a disinfectant. Only UV light of wavelength between 100-280 nm, also known as UVC yeasts in a matter of minutes. Having said that, it should is used for sterilization purposes owing to its high also be mentioned that the time required for killing energy level. It is known to be an effective agent in different microorganisms depends on their shape and deactivating viruses and bacteria. This spectrum of UV size, which influence their UV absorption rate. ray is present in sunlight as well, but it is filtered by the
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DIFFERENT TYPES OF U DI I U Longest wavelength (315-400 nm). Can penetrate the middle layer of your skin (the dermis). Causes aging & wrinkling.
U U U Short wavelength (280-315 nm). U Reaches the outer layer of your skin (the epidermis). Can cause redness, burning or skin cancer. Can penetrate deeper into the skin and eye.
U Shortest wavelength (100-280 nm). Does not reach the earth's surface. Blocked by the ozone layer in the atmosphere. Out of all the three, UVC has the strongest germicidal effect. It destroys the outer protein coating of various disease-causing pathogens.
How does UV sterilization make it happen? Before progressing towards the next section, it is imperative to understand the difference between UVGI - acronym for Ultraviolet germicidal irradiation sterilization, disinfection, and decontamination as works by breaking down certain chemical bonds these terms are often used interchangeably and may and altering the structure of DNA, RNA, and proteins lead to confusion regarding the effectiveness of UVGI. of microorganism, thereby making them unable to multiply. By not being able to multiply anymore within As per the Center for Disease Control (CDC), sterilization a host cell, it would no longer be considered infectious. is the process of eliminating all forms of microbial life and is carried out by physical or chemical means. How long does it actually take before a CDC defines disinfection as the process of eliminating microorganism becomes ineffective? or reducing harmful microorganisms from inanimate Since the UV sterilization process makes use of the objects or surfaces. energy of UVC to destroy biomolecules, it depends Decontamination is the process of reducing microbial on the total energy applied, which in turn depends contamination. It renders all materials safe for use. on exposure time and distance of the light source. In other words, decontamination could be achieved To sterilize E. Coli in laboratory condition, if the light through sterilization or disinfection. source is within 1 inch of the sample, it will take 1-2 minutes for complete sterilization. For sterilizing Given the recent popularity of UV disinfection, certain surgical instruments in a UV chamber, a duration of myths have also become a conversation topic one can 5-10 minutes is recommended. no longer ignore. We have tried to explain, with facts, some of those myths here: https://axenic-uv.com/blog- In terms of virus elimination, studies have shown that detail/Five-misconceptions-around-uv-sanitization- Ultraviolet C light has been effective in killing various debunked strains of the coronavirus, including SARS and MERS. At least 15 minutes of exposure to the UV rays have been found to render the SARS virus ineffective.
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Application of UV Disinfection
ontrary to popular belief, UV technology isn’t observed in the field of UV technology as well. Among a recent innovation; the technology has been other things, the size of a UV light bulb has reduced Caround since a long time. Its application could and its lifespan has increased, which has broadened be traced back to as early as mid-20th century. With the scope of its application in multiple areas. the progress of science, a radical change has been
Five Application Categories:
1 2 Disinfection Disinfection
3 4E 5 Disinfection Disinfection Disinfection
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Air Disinfection involve releasing high power electromagnetic energy through UV light that penetrates and destroys harmful UV light could disinfect air in enclosed spaces as microorganisms, and affects their ability to multiply. well, thereby making it more effective with still or Since it doesn’t involve the use of any chemicals to stagnant air as compared to moving air. To improve clean the water, there’s no risk of negative impact on the effectiveness of UV disinfection, many facilities the environment. choose to install lights near coils and drain pans of cooling systems. Another technology that has caught Surface Disinfection attention in this regard is Upper-room UVC that refers to a system of ultraviolet germicidal irradiation (UVGI) The growing popularity of UV rays has further luminaire fixtures that emit UVC light (100-280 nm) broadened its prospects as surface disinfectant as for disinfection purposes. Such systems are usually well. The cleaning and disinfection become efficient installed in the upper part of a room to destroy floating and effective with UV rays that zap disease-causing particles in the air. pathogens from the immediate surrounding space, leaving behind a clean surface. Equipment Disinfection UV light finds effective use in equipment disinfection. This method is dry and doesn’t leave behind moisture and stains unlike washing and bleaching methods. Several airlines like Boeing have even started testing hand-held UV sanitizers to disinfect sensitive flight equipment, cabins, cockpits, and more. Food & Beverage Disinfection Fresh or raw food material have the highest risk of attracting harmful bacteria and viruses either from Water Disinfection exposure to elements or cross-contamination. UV- based sanitizing methods could be a welcome addition UV light is being used for water disinfection and even in food processing units to reduce cases of disease for wastewater treatment since many years now. The outbreaks and food spoilage. It could also be used to primary reason being freedom from chlorine-based disinfect conveyor belts that are otherwise difficult to water purification processes. UV disinfection methods clean thoroughly.
With UV Disinfection covering such wide application categories, its usage is not limited to healthcare facilities anymore. It can be put to use in almost all kinds of organizations and establishments.
EDUCATIONAL COMMERCIAL GYMS & INSTITUTIONS STORES ATHLETIC CENTERS
HOSPITALS MANUFACTURING WORKPLACES & CLINICS FACILITIES & WAREHOUSES
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Hospitals & Clinics events halted for quite some time now, various teams, stadiums and facilities are turning to UV Disinfection More than any other space, it’s the healthcare facilities devices in order to provide a safer environment to their that put a greater transmission risk of disease-causing players and public alike. pathogens. In fact, one thing that the 2020 pandemic has indeed brought to the forefront is the safety of the Commercial Stores front line workers. Along with ensuring an impeccable germ-free environment for the patients, providing In a bid to provide their customers a safer and cleaner unerring safety to the healthcare workers is equally shopping experience, commercial stores around the important. Owing to which, hospitals place the highest world are adopting numerous safety measures such priority on reducing Hospital Acquired Infections as adequate distancing, allowing a limited number (HAIs), which are also known as nosocomial infections. of people inside the store at a given time, keeping The Centers for Disease Control and Prevention (CDC) disinfectant gel at various points and so on. While estimates that around 2 million people contract HAIs these steps are certainly crucial, disinfecting these annually. Consequently, good hygiene becomes all the stores or marts at large, every day, is indispensable. It more important to prevent pathogen transmission in will not only ensure safety for customers but also for the hospitals. UV disinfection solutions are contactless, staff members, who are equally at risk of transmitting require less time and minimal human intervention – disease-causing pathogens. UV devices can cover all making them potent enough in combating these deadly the high-touch points inside your commercial premises viruses from the high-touch points in a hospital or a and cater to your varied requirements in keeping your clinic setup irrespective of the size. Moreover, since stores clean and germ free. the technology is chemical-free, it doesn’t leave behind any harmful trails that could impact the environment. Workplaces Manufacturing Facilities & Warehouses Even if the world has accustomed itself to Smart Working, going to office, working at your desk with The 2020 pandemic has forced almost all the your team around, getting assembled in the conference manufacturing industries – pharmaceuticals, room, establishing human contact and having a cup of medical devices, clean-room manufacturing, food tea or coffee with your colleagues – is second to none. manufacturing and many more – to make a lot of While engaging in these activities at workplace, a great changes to their existing facilities and warehouses. deal of cleanliness is required to prevent transmission Point to be noted here is that these manufacturing of disease-causing pathogens. After all, a healthy units and warehouses are generally run in a closed and work environment leads to high levels of productivity. controlled environment that make them a hot spot for Keeping this in mind, UV devices can give an all-round the transmission of disease-causing pathogens. That disinfection. Studies have also shown that contrary certainly calls for a greater attention to cleaning and to popular belief, toilet seats are not the most germ- disinfection processes within these spaces to ensure laden surfaces in an office, instead, equipment such as impeccable safety for the workers and subsequently keyboards, coffee machines, telephones among others for the products being manufactured. It is here that are the most contaminated and UV-based solutions UV disinfection solutions can become your bona fide can certainly be helpful for regular disinfection. ally and make sure that along with heavily trafficked areas even dead angles are disinfected in an unerring Educational Institutions manner. Schools, colleges and universities are fundamental in Gyms & Athletic Centers providing children an environment which is conducive for their better future. A place where they spend a In order to keep the athletic centers up and running, major part of their day needs to be safe and germ free a high degree of prudence is required in cleaning, – which is a key to promote children’s right to health. disinfecting & sanitizing these fitness clubs as UV device scan help disinfect high-touch points inside they involve multiple individuals touching the same school premises as they require minimum to zero surfaces or equipment over and over again. Along with human contact and still provide a higher pathogen- routine cleanliness methods, UV-based devices can killing rate ensuring healthy classrooms all the time. actually prevent the spread of MSRA from the high touch points in a fitness club. After all, a place that is meant for the well-being of people shouldn’t make them apprehensive for their health itself. With sporting
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VARIOUS SOURCES OF UV LIGHT LEDS, MERCURY & XENON LAMPS
Mercury Lamps – Though low-pressure mercury range of wavelength is emitted, some impurity could be lamps resemble conventional fluorescent lamps in added to get the required wavelength. appearance, the major difference lies in the fact that the borosilicate glass in conventional lamps is replaced With a mercury lamp, power consumption is high (in the by fused quartz in UVC lamps. UVC lamps also lack the order of thousands of watts/hour) and even the heat fluorescent phosphor. The presence of quartz allows generated is high; and as result the working life doesn’t light produced by the mercury arc to pass through the go beyond 2000 hours. The device can’t be turned on glass unmodified, thus generating lights within the instantly and requires longer cooling and heating time. wavelength that has germicidal properties. It also requires frequent maintenance and produces ozone as well. Mercury lamps emit a vast spectrum of radiations (including visible, UV and IR) from a plasma arc, Xenon Lamps – Xenon arc lamp is a type of gas which is located between two electrodes. The arc discharge lamp that generates light when electricity is is maintained inside a quartz tube. The arc, when passed through ionized xenon gas under high pressure. heated uniformly radiates electromagnetic waves of Xenon short-arc lamp emits significant amount of all possible wavelengths in all directions. Since a huge UV radiation. Xenon lamp generally has two major
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categories - One where the tube is filled with only xenon current is passed through it. A typical UV LED device gas, and another that has a small portion of mercury. is monochromatic and emits a single wavelength. It is The construction of this type of lamp includes a fused possible to manufacture a UV LED device generating silica tube, a cathode, and an anode. It also emits a any wavelength between 250 nm and 400 nm. It is wide range of electromagnetic spectrum. Although the also worth mentioning that unlike mercury lamps, UV xenon lamp is effective and is also energy efficient, it LEDs do not emit any infrared radiation. With a UV LED has a negative environmental effect as it generates device, power consumption is low (limited to hundreds ozone. of Watts/hour). The low heat generation contributes to the extended life of the lamp (20,000 - 50,000 working There are also Mercury-Xenon lamps that combine hours). Furthermore, the LED device could be switched the characteristics of both. These combination lamps on instantly and can be used on heat sensitive materials. provide high radiant energy in the UV region. Mercury- xenon lamps also feature instantaneous lighting and re-lighting, which are difficult to obtain in high pressure mercury lamps. These lamps can give more stability and lifespan than a xenon or a mercury lamp separately.
UV LED Lamps – A UV LED (short for light- emitting diode), on the other hand, emits a narrow band of radiation around a single peak wavelength. It’s a semiconductor device that emits light when a JANUS UV BULKHEAD DISINFECTION LAMP
Comparison of UV LED, UV Mercury Lamps & UV Xenon Lamps
Factors UV LED UV Mercury UV Xenon System Core UV LED is made of UV Mercury lamps UV Xenon lamps semiconductor contain fused quartz fused quartz enve- materials (silicon) and mercury lope with thoriated and doesn’t con- tungsten electrodes tain mercury
Power Consumption Low High High
Lifetime 20000 – 40000 500 – 2000 1000-5000 working hours working hours working hours
Heat generated Low High High
Switching On/Off No waiting time It takes time to heat It takes time to heat involved up and cool off up and cool off
Cooling System Air cooling As ozone is emitted Air or water cool- it needs blowers and ing. Also, as ozone pipes to carry them is emitted it needs outside proper ventilation
Environmental Impact Has no effect on Mercury present Generates either environment could be dangerous mercury or ozone for the environment Maintenance Required Minimum. Only Frequent mainte- Regular cleaning of glass cleaning nance and period- humidifier & fuselage required ic replacement of and periodic re- bulbs placement of Xenon bulbs
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BENEFITS OF UV LEDs
t has been observed in recent years that UV LED Instant On/Off – Unlike LED systems, mercury lamps based lamps have begun to replace their mercury cannot be turned on instantly. It requires sufficient Icounterparts. This may be due to the following warm up time. As a result, in practice, mercury lamps are benefits offered by the LED based lamps: left on running at low power, which eventually leads to wastage of energy. With UV LEDs, none of these issues Environmental Impact – UV LEDs have less occur because these devices can be switched on/off impact on the environment as compared to alternative instantly, are energy efficient, and have dedicated heat technologies. Moreover, it consumes 70% less energy dissipation systems. than cold-cathode florescent lamps (CCFLs). Unlike fluorescent lamps, UV LEDs do not contain mercury. Performance – With UV LEDs, emissions can be directly focused on the work surface, which can’t Improved Lifespan – UV LEDs are smaller in size be done with ordinary UV lamps as they require and are more durable than CCFLs, which gets reflected enough light to be flashed on the work surface to hit in its increased lifespan. The UV LEDs are also much the right combination of uniformity and intensity. A more resistant to vibration and impacts, resulting in mercury lamp emits only 20% of the energy as UV fewer wastage of equipment due to product breakage. light. It operates at high temperature, which can The UV LEDs that we are so used to weren’t nearly half affect heat sensitive surfaces. This can limit the as good a decade ago. The new generation products usage of mercury lamps to a few selective materials. now boast a lifespan of 50,000 hours. On the other In contrast, UV LEDs provide greater control and hand, lifespan of a mercury lamp ranges between 1500 stability of output. - 2000 hours
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Cost-effectiveness – Since UV LEDs do not require It is worth mentioning that only 30 to 40% of the input frequent maintenance and consume low power, it power is converted into UV radiation and the rest gets provides economic advantage as well. The overall lost as heat. It means, a 1 mm2 chip will emit 1-watt operations cost and investment in such lights lead to worth of UV power. The irradiance which is the power better return on investment (ROI) in the form of energy received by a surface per unit area is 1 W/mm2 (or 100 savings. Rapid technological innovation in this realm W/cm2) at the surface of the chip. Of course, not all the coupled with constantly looming threat of epidemics irradiance can be delivered to a work surface because and pandemics has made adoption of UV LED-based of the way the radiation is emitted. disinfection devices a frequent occurrence these days. LED is a sensitive device and voltage fluctuations Hospitals, manufacturing units, retail stores, education could damage the device beyond repair. It should be institutions, and airports have been actively testing out remembered that LEDs have to be exposed only to the and using such products. Such encouraging trends are required voltage. The power supply of LED is designed bound to expand the market for latest UV LEDs that are keeping all these things in mind. The intensity of the not just affordable but energy efficient as well. UV radiation produced by UV LEDs could be controlled Chemical-free – One of the biggest advantages of by reducing the flow of current through the device. This UVC light disinfection methods is that they are chemical- feature of intensity control makes UV LED devices the free. A common problem with chemical-based cleaning best among other options. solutions is that they can damage equipment, and corrode or destroy surfaces. In August 2020, Florida’s Cooling System – As previously mentioned, most Atlas Aviation had to bear damages to the expensive of the input electric power gets converted as heat by a cockpit instrument panels of its aircrafts due to the typical UV LED system. This heat needs to be removed improper use of chemical-based disinfectants. UV- from the LED system as it can affect its operations. The based technology, which is absolutely chemical- interior of an LED shouldn’t be exposed to temperatures free and leaves no residue can be an answer to such above 125°C. Instead, the temperature should be kept problems. The same was echoed by Boeing as they as low as possible since overheating could reduce the began testing hand-held UV wand sanitizers instead lifespan of such devices. This necessitates the use of of chemical-based cleaning solutions in order to avoid a cooling system to move heat away from the hundreds using alcohol or other disinfectants that could damage of LED chips that are present in a typical UV LED curing sensitive electronic equipment. system. A typical UV LED system makes use of water- cooling system. Air cooling system can be used in Technical features of the UV-LED system – The lower power UV LED systems. wavelength generated by UV-LED lamps depend on the The presence of a cooling system can give rise to the characteristics of diodes used for the manufacturing of possibility of moisture or condensation on LEDs inside such lamps. The system works when electric current is the UV LED curing system, which could lead to short passed through chips at a specific voltage. Only a few circuit. Therefore, UV LED systems are designed in a percentage of the power supplied gets converted to way that condensation can be prevented. UV rays of the required wavelength and the remaining power gets dissipated as heat. In this section, we’ll Irradiance Obtained – Although the irradiance discuss about some of the specific features of UV LED at the surface of a UV LED system is quite large, it is systems. difficult to deliver the same on a work surface as UV ray is emitted in many directions. To make it work Power Supply – The power supply required for effectively, the UV LED system should be placed close the functioning of an LED is the current source. The to the surface as the irradiance follows inverse square amperage, which is a measure of current, determines law - with the increase in distance the irradiance drops. the amount of UV power emitted by the LED. The current which when flows through the LED chip generates The loss in irradiance can also be caused by the UV power. The usual dimensions of the chip ranges presence of empty space in between arrays of chips between 1 mm2 and 4 mm2, and the current that can that make up the UV LED curing system. Since the flow through the chip ranges between 1 and 6 amps. irradiance drops quickly as the system is moved away The current flowing through the LED depends on the from the work surface, manufacturers of commercial applied voltage. UV LED systems quote the irradiance delivered at the exit window of the LED module. An LED light which emits UV rays of 385 nm requires a voltage between 3 to 3.5 Volts to drive the current through the device. A 1 mm2 chip which is operating at 1 amp current and 3 volts voltage will be operational at 3 watts. (Since, electric power, which is measured in watt, is a multiple of current and voltage.)
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TYPES OF UV DISINFECTION DEVICES
V Disinfection devices can be broadly categorized to use. This is beneficial in areas which require frequent into robotic, wall-mounted, ceiling-mounted and disinfection like hospital rooms or hotel rooms. Mobile Umobile devices. UV devices could either come with casters at the bottom that allow for their free movement to the areas Mobile UV Devices – The biggest advantage that need to be disinfected or could be handheld for associated with a mobile UV disinfection unit is that it congested areas to hit the right spots with germicidal could be moved around to disinfect different spaces. UV light. Such devices can be used both for small or Unlike ceiling or wall mounted UV disinfection products, large areas depending on their size. this device doesn’t work on schedule and is convenient
INTENZA AEROMAXE BEAMER STALWART PRO MOBILE UNIT MICROWAVE INDUCTION AIR HIGH POWER UV UVC DISINFECTION UV STERILIZER STERILIZER GERMICIDAL LAMP HIGH BAY
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UV Robots – UV robots can patrol for sterilization gained momentum. and disinfection in predetermined area. The robots are capable of carrying out operations on their own through Upper-room UVC refers to a system of ultraviolet in-built navigation system and contactless operations. germicidal irradiation (UVGI) luminaire fixtures that Some also come with automatic charging and laser- emit UVC light (100-280 nm) for disinfection purposes. based obstruction detection for smooth disinfection of Such systems are usually installed in the upper part of all kinds of surfaces, even hard to reach corners. a room to destroy harmful pathogens from the air and create a more hygienic environment.
Air disinfection is the primary purpose of upper-room UVC devices. Various studies suggest that for these devices to work effectively, they should be installed at an approximate minimum height of 7 feet measured from the bottom of the fixture to the floor. They work by projecting UVC light across the upper room space. While that happens, various microorganisms like bacteria & viruses present in the air get transported towards the ultraviolet field by convection currents, where they are rendered inactive by the UV light, and SANI BOT finally get destroyed. UVC + ATOMIZER SPRAY DISINFECTION ROBOT Find more information on Upper-room UV here: https:// axenic-uv.com/blog-detail/what-is-upper-room- Ceiling-mounted UV Devices–These are generally germicidal-uv-is-it-safe-for-humans used for air disinfection and come in the form of UV LED Panel Lights. They have antiseptic and antiviral nanomaterial/s and come with a Centrifugal Industrial Fan that cleanses the air of bacteria and pathogens. Their silver ions that are widely used in disinfection and sterilization processes, react with hydrogen sulfide ions in bacteria and damage their DNA along with their protein structure, thus inhibiting their reproduction.
EXERGIA EFFICA MICROWAVE UV UVC DISINFECTION STERILIZER BAR T8 TUBE
AEROMAXE PRO UPPER ROOM AIR INDIRECT GERMICIDAL UV FIXTURE HOVER LED UV DISINFECTION PANEL LIGHT
Wall- Mounted UV Devices – Wall-mounted UV devices are perfect for highly frequented places such as hospitals, restaurants, shopping malls, gyms etc. Since these are fixed on the wall and are controlled by a remote switch, no cleaning staff is required to put them to use. These devices are suitable for effortless regular cleaning. Depending on their technical features these can be used both for surface and air disinfection.
Upper-room UV is another wall-mounted UV technology that is being tested since many years and has recently
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UVC LIGHT & HUMAN SAFETY
n the previous sections we’ve discussed about the of any access point de-energizes the system and no effectiveness of ultraviolet light as a disinfectant. UV one is exposed to the radiation. light alters the genetic materials of pathogens, thereby I • Instructing service personnel to refrain from directly rendering them ineffective. But the question that needs to be asked is - does the light harm mammalian skin looking at UVC without proper eye protection is cells as well? necessary. Installing a view port is recommended as it ensures safety. The entire bandwidth of UVC It actually depends on the wavelength of the UV ray is blocked by it. and the duration of exposure. Most of us are familiar with sun burns caused by UV energy transmitted by • It’s recommended to never enter the plenum where sunlight in the UVA and UVB wavelengths. But unlike UVC lamps are active. If it’s absolutely necessary these two types, UVC, which are of shorter wavelengths, to enter the plenum then wear personal protective carry more than twice the energy carried by UVA. UVCs equipment which includes face shield, safety also get absorbed well by organic substances, thereby goggles, gloves, and full-sleeved tightly woven adding to its effectiveness. clothes that cover much of the body.
The high energy of UVC is required to degrade genetic Before progressing to the next section, it should be material like DNA of microbes so they can’t multiply. noted that intensity of radiation from point sources like But this can cause painful burns on the skin and can UV LEDs fall off as one moves away from it. This is due temporarily damage cornea if observed directly. It is also to the inverse square rule and once someone moves past known to be carcinogenic. Thankfully though, it doesn’t the scattering length the intensity falls off exponentially. naturally impact humans because UVC from the sun is It means if someone is far away from the UVC source absorbed by the Earth’s ozone layer and atmosphere. then they would be exposed to almost negligible dose of radiation. Furthermore, the absorption length of UVC Nevertheless, certain safety procedures have to be radiation in human skin is extremely short, so negligible followed when dealing with UVC lamps: UVC radiations can’t reach past the dead cells to the living cells. All the UVC gets absorbed in the dead cell • Warning labels have to be put on doors or panels to layers. It is still important to sanitize even when minimal plenums containing UV lamps. contact is made with the skin to avoid any serious issues. • Electrical disconnect devices should be installed on Air Handling Unit lamp sections, so that the opening
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LATEST DEVELOPMENTS IN UV DISINFECTION
ith each passing day UV technology is showing also been commercialized but have lesser appeal to progress in chip design, optics, and efficiency. LED manufacturers due to its perceived limited area of WFollowing are some of the latest developments application. For UVC LEDs, it is rightly said that as more made in the field of UVC disinfection. players enter the market, efficiency and reliability will increase and prices will come down as such devices UVA LEDs – With the advancement of technology, UV continue to be majorly used for disinfection processes. LED is displaying a gradual change in terms of new LED chip designs, better UV optics, and efficiency. Truth be UVA-UVC LEDs – The gradual improvement of told, one can’t expect much improvement in efficiency technology could lead to the development of a mixed as the UVA LED technology is relatively mature. The UVA-UVC LED system. One major concern though biggest changes will be observed in chip design that would be the high costs that will be associated with will allow UVA LEDs to be packed more tightly together. such systems. It will also require particular attention It should be mentioned that the UV LED market has in design so that such systems could deliver uniform similarity with the blue LED market. Since the UVA and wavelength mixed radiation. Going by such trends, it blue LED chips and the technology involved are similar, can be concluded for now that UV LED curing system it’s only fair to expect that any changes observed in the has a tremendous potential and a bright future ahead. blue LED lighting technology will get extended to the UVA LED industry as well. It’s estimated that there will Aexnic-UV’s Effica, a T8 UV Germicidal LED Tube, is be a continuous price reduction in manufacturing UV one such recent development that has a combination LEDs with new players entering the market everyday. of both UVA and UVC. This will lead to shift in user base from mercury-based UV lamp system to LED UV lamp system.
UVC LEDs – Despite the progress observed in the UVA LED market, a shortcoming that is stopping the UV LED industry from growing to its full potential is the absence of high power UVC LEDs. But the situation is gradually changing. Today, there is greater emphasis on UVC LED research in order to develop LEDs that can produce UV emissions in the range of 265-280 nm. In this range, it has been observed that longer Effica with UVC 260 nm + UVA 340 nm the wavelength, better the efficiency. UVB LEDs have
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FAR-UVC – The discussion on the latest development The term ‘Far-UVC’ is a subset of the UVC wavelengths of UV disinfection technology is incomplete without and when the light falls on humans, it gets absorbed mentioning Far-UVC. The wavelength between Far-UVC by the superficial and dead layers of the skin. These varies between 207-222 nm. Several studies have been layers help in shielding the healthy skin and eye cells published highlighting the significance of Far-UVC in from harmful rays. Lab tests conducted on the effect of indoor disinfection and human safety. It has also been Far-UVC on living beings revealed that it cannot lead to proven that Far-UVC light (222 nm) can effectively development of tumor even after regular exposure, but destroy airborne human coronaviruses. conclusive evidence is still awaited.
Before progressing any further, a little background is Nonetheless, this goes on to show that constant necessary. The UVC ray which has been elevated to innovation is what will drive the growth and rapid the status of a ‘saviour’ doesn’t discriminate when it adoption of Far-UVC in disinfection and sanitization comes to damaging genetic materials. This is where practices. the concept of ‘Far-UVC’ light, a supposed exception to the harmful UVC ray, comes in.
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A : 8470 Allison Pointe Blvd, Suite 128 Indianapolis, IN 46250 M : (1)8333-AXENIC(293642)
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