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What is UV-C light?


Ultraviolet light belongs to the electromagnetic spectrum with a wavelength of between 200 and 400 nm (nanometres), which is shorter than that of visible light, but longer than X-rays. All rays and UV bands are invisible to the human eye.

The UV spectrum can be divided into the following bands:

  • UV-A (long waves; 400 – 315 nm) Applications: black lights, skin tanning, hardening with ink/resin.
  • UV-B (average waves; 315 – 280 nm): Applications: psoriasis therapy, it can cause sunburn, skin cancers.
  • UV-C (short waves; 280 – 200nm): Applications: Effective as a germicidal agent and pathogen disinfectant.
  • UV-V (less than 200 nm): Applications: Produces ozone by recombining oxygen atoms in the air.
All of the above wavelengths of UV light are emitted by the sun, but only the longest wavelengths, UV-A and UV-B reach the earth. UV-C rays, which are the shortest wavelength but with the highest energy are blocked by the ozone layer.




How does UV-C destroy harmful microorganisms?


Because UV-C rays are blocked by the ozone layer, microorganisms have not developed a natural defence against UV-C energy. When the DNA of a microorganism absorbs UV-C energy, molecular instability occurs, resulting in an abortion of the DNA sequence. This renders the cell unable to grow or reproduce. Without the ability to reproduce, the cell cannot infect and dies quickly.

The application of UV-C energy to deactivate microorganisms is known as germicide radiation or UV-GI. It has been used for this purpose since the early 1900s. Artificial UV-C energy is produced in germicide ultraviolet lamps that produce UV radiation by ionizing low-pressure mercury vapor. These lamps are similar to typical fluorescent lamps for home use, but do not have the phosphorescent coating that transmits soft white light. Most commercial UV-C lamps are low-pressure mercury lamps that emit UV energy at 253.7 nm, which is an ideal wavelength for disrupting the DNA of microorganisms.


UV-C lamps and devices are increasingly being used around the world in various configurations and applications to disinfect water, air, and surfaces.

The amount of UV-C energy required to inactivate a given microorganism is measured by dose, which is determined by a combination of radiation energy and exposure time. A key difference between surface deactivation and deactivation of microorganisms in air is exposure time. The time exposure in the UV field for microorganisms in the air is of the order of seconds and would require a much higher UV-C dose than that used for surface application.

Scientists determined the rate at which various microbial populations decrease due to exposure to biocide factors such as UV-C irradiation. Organisms differ in their susceptibility to UV-C inactivation; In general, viruses are the most sensitive to UV-C rays followed by bacteria with mould and fungal spores that are the least sensitive.

UV-C irradiation also obeys the inverse-square law of light, where the intensity at a given point is inversely proportional to the square of its distance from the light source.

Based on mathematical modelling, engineers developed proprietary and third-party computer modelling programs to estimate decommissioning rates for target microorganisms and then designed UV-C systems that will efficiently and effectively disinfect the air, surface or water according to the situation of interest




Is the use of UV-C safe?


Ultraviolet germicide irradiation used for the disinfection of water, air and surface is a biocide for microorganisms and extremely effective in deactivating harmful bacteria and viruses. The application of UV-C in the Evolve Raybotix Robots has been designed with maximum safety in mind – with an automatic abort function if movement is detected whilst in operation. Excessive direct UV exposure (no barrier present) can cause some risk to human health – for example eye damage in the form of keratitis photos and conjunctivitis. These symptoms usually appear within 6-12 hours of UV exposure and resolve within 24-48 hours. Direct prolonged exposure to ultraviolet radiation can also affect the skin and cause erythema (skin redness) much like when exposed to the sun for long periods. Most UV-C rays are reflected and absorbed by the outer dead layer of human skin, thus minimizing UV-C rays transmitted through the epidermal layer.

Appropriate personal protective equipment (PPE such as Safety Specs and UV Protective Clothing) is recommended when staff may be exposed directly to UV radiation.




How do UV-C rays disinfect?


UV-C germicide systems artificially generate a wavelength of 254 nm of light that destroys the DNA of microorganisms including viruses, bacteria and mould. Once deactivated, these microorganisms are no longer able to reproduce and grow on surfaces. In addition to disinfection of surfaces, UV-C also helps improve indoor air quality through compound breakdown and offers a more energy efficient sanitisation process than traditional methods which include use of toxic/hazardous/irritant chemicals.




Is the UV-C system effective?


Yes, scientific and anecdotal references are abounding in the effectiveness of UV-C in both literature and field application reports. Government reports, NIOSH, OSHA, CDC, GSA, EPA are the most notable. The science in the public forum from the University of Cincinnati, the University of Tulsa, the University of Colorado, and McGill University (Canada) are some examples. UV-C is used worldwide and well recognised for its disinfection properties, low energy/cost, and low H&S risk.




Does UV-C light alone kill 99.9% of bacteria? What additional assurances does the Ozone feature offer?


UV-C rays are effective where there is direct radiation onto space and surfaces. The emission of Ozone enables disinfection of shadowed areas and blind spots. Effectively all areas exposed to air in the exposed room will be disinfected with the Ozone oxidation action.




If UV-C rays are not visible, what is the blue light emitted by the lamp?


UV-C is the invisible part of the light spectrum. The blue colour comes from the inert gas inside the UV-C bulb. The light bulb can be turned on (and blue) but does not produce UV-C energy.




Does the UV-C device produce chemicals or by-products?


No, however, there may be a particular odour that is created due to the rupture of volatile organic compounds present in the air.




What does UV "C" or UV "GI" mean??


The letters "UV" refer to the spectrum of magnetic wavelengths known as ultraviolet light. This spectrum is most often divided into four categories: vacuum, short waves, medium waves and long waves 'or UVV, UV-C, UVB and UVA. UV-C is the most germicidal frequency and the term UVGI refers to "ultraviolet germicide irradiation" used by federal agencies such as OSHA, NIOSH, GSA, EPA and CDC when referring directly to UV-C.




Do UV-C lamps produce ozone?


UV-C lamps do not produce Ozone. UV-V lamps can produce Ozone. The UV-C provides exceptional air conditioning, very much like the sunshine outdoors. UV-C fixtures are a component for air conditioning that is added to other parts of the system. These include filters, coil, heating core, fan, shutters, humidifiers, etc. All are designed to provide a specific function in the work of air treatment for occupied spaces.




If I can't see UV-C energy, what do I see?


About 90% of the energy generated by a UV-C lamp is UV-C energy, the rest is visible light (blue shades) and a small amount of infrared (heat). Given the brightness of UV-C lamps, that 3-4% of visible light gives an idea of the amount of UV-C energy produced by a lamp.




Can UV-C rays kill dust mites?


There is no evidence that a UV-C dose suitable for a given killing of microbes has any effect on dust mites. Very high UV-C energy or long-term exposure to UV-C rays should disrupt some of the mite's biological functions, which can lead to death.




How is a UV-C system sized?


The Evolve Raybotix UV-C disinfection robots use proprietary software to accurately size a UV-C system for an application. The software model takes into account various parameters such as the type of microorganism(s), the size of the plenum/area or any cavities present, the air flow, the reflectivity of the walls, the temperature and humidity.




How long does UV-C take to kill microorganisms?


The UV-C dose required to deactivate a specific organism depends on the type of target microorganism, the UV-C intensity applied and the time of exposure to UV-C. The Evolve Raybotix UV-C disinfection robots have a large in-built database of dose values required to deactivate various bacteria, viruses and mould.




Do shading or shadows in the room affect the effectiveness of the UV-C robot?


Studies in the literature show that the concentration of pathogens, organic load and shading from the direct radiation field have not reduced the effectiveness of the robots. However, it is recommended that they are positioned to operate in multiple locations in a room to maximize the number of surfaces that are directly exposed to the UV-C light.




What is the effectiveness of UV-C disinfection robots against endospores such as C. diff and bacillus strains?


The UV-C intensity of the robots allows the endospores to be deactivated in as little as 5 minutes. This has been demonstrated in laboratory studies, studies on the hospital environment and validated in studies on outcomes showing reductions in C. diff rates reported by different hospitals using the same technologies.




Do all UV-C lamps contain mercury to be germicide? Do all UV-C lamps produce an ozone smell?


Most UV lamps used for UV disinfection contain mercury. In the case of low-pressure lamps, there are only a few milligrams of mercury. In the case of medium-pressure lamps, which have a much higher power, there are a few grams.
Low- and medium-pressure lamps generate ozone if they have a very pure (synthetic) quartz casing, which allows the mercury emission of 185 nm to enter the air. This UV light is absorbed by oxygen into the air to generate ozone. Most UV lamps are made with a quartz shape that contains impurities that completely absorb the emission of 185 nm, so as not to produce ozone.




How do I calculate ultraviolet radiation?


The intensity of UV radiation is measured in units of milliwatts per square centimetre (mW/cm2) which is the energy per square centimetre received per second. In addition, it is measured in units of millijoules per square centimetre (mJ/cm2), which is the energy received per unit of surface in a given time.




Can germicide UV-C penetrate surfaces or substances?


No – UV-C germicide sterilizes only what it comes into contact with.




How do you determine the area that will cover a germicide UV-C lamp?


This is determined by the power of the lamp. Example: A 15-watt lamp will cover about 10m2. Higher powered lamps mean a higher area of effectiveness.




How much intensity of UV-C do I need to kill certain organisms?


Exposure of the germicide UV-C ultraviolet is the product of time and intensity. High intensity for a short period and low intensity over a long period are basically the same in lethal action on bacteria. The law of the inverse square applies to the germicide ultraviolet as well as to light: the killing power decreases as the distance from the lamps increases. The average bacterium will be killed in ten seconds at a distance of six inches from the lamp.




Will germicide UV-C take care of mould?


Yes. UV-C germicide lamps will kill up to 99.9% mould and help prevent future mould growth.




Do germicide UV-C amps kill viruses?


Yes, germicide UV-C lamps kill up to 99.9% of most viruses, bacteria dispersed in the air and mould spores.





UV-C Explained

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How does ozone work?


Ozone kills bacteria by destroying their cell wall. Once the cell wall is destroyed, the bacteria will not be able to survive. The third ozone oxygen atom is extremely reactive because it is unstable. This atom easily attaches to other odour molecules. When contaminants such as odours, bacteria or viruses come into contact with ozone, their chemical structure is changed to less odorous compounds. While more ozone attacks the remaining compounds, the odour is eventually destroyed. This process is called oxidation. Ozone essentially returns to oxygen after being used. This makes it a very environmentally friendly oxidant.




What kind of odours does Ozone eliminate?


Ozone neutralizes bacteria and moulds which are the main cause of odours generated and breaks down compounds in air. Therefore, any odours, including nicotine, are eliminated and not simply disguised.




How long does ozone last?


As soon as ozone forms in a generator and disperses into a room, part of it returns to oxygen (O2). This step occurs in several processes, including the following: (i) oxidation reacts with an organic material such as odours or smoke. (ii) reactions with bacteria, etc., which again consume ozone for oxidation reactions.


In addition, ozone breaks thermally. Higher temperatures destroy ozone faster than lower temperatures. The remaining ozone is called residual ozone. The "residual" ozone created will return to oxygen usually within 30 minutes, in amounts equal to half its level. This means that after each subsequent 30-minute period at the end of the period, half of the residual ozone that was present at the beginning of the period would remain. This is similar to a geometric progression of 16; 8; 4; 2; 1. In practice, the half-life is generally less than 30 minutes due to temperature, dust and other contaminants in the air.


Therefore, ozone, although very powerful, does not last long. It does the job and then disappears back into safe ‘oxygen’ in air.




What is the right ozone level?


The right level of ozone is when all the ozone generated is consumed. This applies only to the continuous use of ozone in busy environments, not for the treatment of shocks. However, this is difficult to achieve because the process is a balancing act. Initially the output of the machine is set to eliminate the odour problem as quickly as possible. While this is being realised, less ozone is needed for the decreasing odour, etc., thus leaving excess ozone residue in the air. If the machine output is not lowered, excess ozone will remain. If you notice a strong ozone smell, then there is more ozone than is necessary, and it is suggested to aerate and leave the room stand for few minutes (the unit will ensure ozone levels returns to safe levels before cycle completion). Note: Ozone does not need to be detected by humans to be effective. Ozone can work even when humans are unable to smell it.




When should I use ozone-producing lamps?


UV-C germicide lamps generate power at 185nm and 254 nm. This UV-C emission produces copious amounts of ozone in the air. Ozone is an extremely active oxidant and destroys microorganisms in air on contact. Ozone doubles also as a deodorant. Another advantage is that it can reach shadowed areas and blind spots that UV-C radiation cannot reach directly.




From our understanding the UV lights neutralise the Ozone O3 molecules back to Oxygen O2. How long does this process take?


The Ozone molecules are converted back to O2 towards the end of each cycle. The neutralising period takes approximately 20% of the entire cycle time and is calculated/executed automatically.




Can you set the Robot to use UV-C only without Ozone?


Yes – the robot can be programmed to disinfect using the UV-C feature exclusively.




Is there a way of testing the ozone levels once a room / area has been cleaned?


An Ozone meter can be utilised to determine levels remaining following completion of cycle. The unit does not operate at Ozone levels which are harmful to humans and integrates a neutralising phase into the cycle so O3 is eliminated before individuals return to the space.





Ozone Explained

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What are the health and safety operational requirements to using the machine?


The UV-C disinfection robots are suitable for every environment due to the low voltage equipment feature and its electromagnetic compatibility. This feature limits the penetration to every kind of material including garments and food. However, prolonged exposure to UV rays can cause photo degradation of organic and synthetic materials. Most photographic degradation can occur only on the immediate surface of a material and/or manifest itself as fading or discolouration. The degree to which an object might be susceptible to UV degradation should be considered in any application where exposure can be prolonged. It is advisable to protect valuable or delicate artwork to avoid any damage through longer term exposure to UV-C light.

Long-term exposure of germicide UV-C light to plastic reduces the shelf life of plastic by about 10%. Example: If the plastic normally lasts about ten years and is exposed to UV-C germicide light all the time, it should probably be replaced in 9 years. Plant life can be damaged by direct germicide ultraviolet rays or reflections. Dyes and transient colours can be faded by prolonged exposure to ultraviolet rays.




Is ozone harmful and what are the long-term effects?


Several regulatory agencies, including the Occupational Safety and Health Administration (OSHA), have determined that the permitted residual safety level is 0.1 ppm (parts per million). Note that this allowed level is for continuous exposure for a full day of 8 hours. The robots operate at an Ozone concentration of 0.05 ppm (parts per million) which is within human safety levels. The temporary effects of such low exposure range from headaches, to sore throats and irritation of the eyes and nose. No long-term effect has ever been documented by ozone exposure.

The robots operate at an Ozone concentration of 0.05 ppm (parts per million) which is within human safety levels.




What effects does the UV-C and Ozone have on plants, exposure to food, working surfaces, electronics, garden centres, computer spaces etc?


Prolonged exposure to UV can cause photo degradation of organic and synthetic materials. Owing to the short wavelength, UV-C transmissivity tends to be very low for most materials; therefore, most of the photo degradation may occur only on the immediate surface of a material, and/or manifest itself as fading or discoloration. The degree to which an object might be susceptible to UV degradation needs to be considered in any application where exposure may be prolonged.




How do you know when it is safe to re-enter a room? Does it produce a safety report upon completion of cycle stating the levels of ozone have been neutralised?  Is it safe to enter once the cleaning cycle has finished or do you have to leave the area to “settle”?


The space can be entered as soon as the disinfection cycle has finished. The programme schedules appropriate time for Ozone levels to be transformed (back to Oxygen) down to a maximum of 0.05 parts per million, far below the levels considered harmful to people.




Are there EU regulations for ozone limits / use?


There are no EU regulations for Ozone limits; but levels in excess of 0.3 ppm is classed as harmful to humans.




Is it safe to look at the device through a window while it is running?


Yes. UV-C waves cannot penetrate through glass; therefore, it is safe to be on the other side of a window. The movement sensor (if activated) however can notice you and abort the cycle.




If a person enters a room, we understand the robot immediately aborts the cleaning process.  Does it offer a warning to the person who has entered?


Yes. A chromatic variation of the LEDs to red indicates the cleaning process has been aborted. The machine stops immediately upon sensing any movement of a human or otherwise and lamps are shut down.





Health & Safety

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What is the approximate timescale of disinfection per square metre?





What reporting system is in place?


The scope of the report is to trace the disinfection cycle. The report is generated in PDF format and can be downloaded directly onto any smart device, hence can be saved digitally, mailed or printed. The reports can be used for auditing purposes as they provide a clear record of the disinfection activity, date, time, operator and any accompanying notes relevant for the report.




What languages does the software operate in?


  • Italian
  • English
  • French
  • Spanish




Do you have to set the robot to map out each area and record it in a memory bank?


The robot automatically maps the area when being used in a space for the first time. This takes a few minutes, depending on the size and surfaces within the space. Once each area has been mapped; it is stored in the library ready for selection each time that space is being disinfected.




If a room stored in the library is temporarily inaccessible, will the robot report that this area has not been cleansed?


The robot will not develop a report for any rooms that have not been cleansed. We recommend the user maintaining a record of the proposed disinfection ‘route’ and those completed so any un-sanitised spaces can be returned to when accessible. The robot notifies the user whenever new elements such as new furniture is placed in a previously mapped room. In such cases a new room map is required for a continuous effective disinfection run.




In relation to the mobility of the robots, what flooring surfaces and incline can they navigate?


The robot can navigate most underfoot surfaces. The Sol model can handle 5-7% incline at a reduced speed.




Is the app downloadable on any iPad/Smart phone?


Authorised users can log in through a web portal using a tablet, smartphone or any other device equipped with wi-fi and a browser. The robot has its own wi-fi hotspot which the user connects to. No App download is necessary.




How is each robot activated?


The robots can only be activated using a username and authorised password. Every user has an individual password assigned to them. Remote assistance to recover any passwords is also provided.




Do lamps need a power supply to work?


Yes: a germicide lamp is part of a system and the system cannot be fully defined and optimized unless the lamp and reactor combination are determined. It is the interaction between lamp and reactor that is the real determining factor in the system's performance.




Is there a ‘fast clean’ setting?


The robots benefit from a quick mode or a personal settings mode according to needs, especially for a fast turnaround of space. However, the efficacy of the robots UV-C light may be affected through adjusting the time away from what is recommended.




Is there any indication of time/money saved/efficiency of virus elimination when using robots versus general cleaning?


The only cost of using the UV-C disinfection robots is energy and lamp replacement (approximately every 16,000 hours). Disinfection is carried out using Oxygen in the air which is abundant, free of charge and environmentally friendly. There is no purchase or transportation of harmful chemicals as with traditional cleaning/disinfection and the consistency of sanitisation is far higher using UV-C with Ozone that from an individual cleaner whose standard can differ from one and the other and from day to day.




What cleaning is recommended (if any) prior to using a UV-C disinfection robot?


Disinfection does not replace cleaning: dust, dirt and debris must be removed first. We would recommend using the UV-C disinfection robot as a final step in the cleaning process and in addition to regular disinfection of surfaces and spaces where possible.




How long does disinfection last?


After disinfection, the room will remain very low microbial load until new pathogens enter the room from a visitor. If properly cleaned and disinfected, the decontamination procedure does not need to be repeated until new ‘contamination’ has occurred i.e. room occupied by new visitor.




What is the right position for the UV-C robot?


The UV-C dose received in a room normally equipped after decontamination with a mobile unit that emits UV-C varies depending on the distance between the light source and the irradiated area and any object between those shadows. It is necessary to ensure that an adequate dose has been received in shaded and/or critical areas. Disposable indicators can help ensure that an adequate dose has been received.

As the distance from the lamp increases, the effectiveness against microorganisms decreases drastically, requiring a multiple placement in the room to achieve even partial disinfection.

Evolve Raybotix robots work via an automated, remote-managed system that self-regulates based on the size and dynamics of a room's contents to provide the right dose of UV-C light. Our technology uses the tool to measure UV-C light in a combined way that is diverted to shaded and indirect areas for terminal disinfection. When energy is diverted around the room, shadowed areas are reached and pathogens are eliminated ensuring a complete disinfection result, each time.




To be effective, how close do they need to be to the surface?


Exposure of the germicide ultraviolet is the product of time and intensity. High intensity for a short period and low intensity over a long period are basically the same in lethal action on bacteria. The law of the inverse square applies to the germicide ultraviolet as well as to light: the killing power decreases as the distance from the lamps increases. The average bacterium will be killed in ten seconds at a distance of six inches from the lamp.





Operations

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What is the approximate timescale of disinfection per square metre?





What reporting system is in place?


The scope of the report is to trace the disinfection cycle. The report is generated in PDF format and can be downloaded directly onto any smart device, hence can be saved digitally, mailed or printed. The reports can be used for auditing purposes as they provide a clear record of the disinfection activity, date, time, operator and any accompanying notes relevant for the report.




What languages does the software operate in?


  • Italian
  • English
  • French
  • Spanish




Do you have to set the robot to map out each area and record it in a memory bank?


The robot automatically maps the area when being used in a space for the first time. This takes a few minutes, depending on the size and surfaces within the space. Once each area has been mapped; it is stored in the library ready for selection each time that space is being disinfected.




If a room stored in the library is temporarily inaccessible, will the robot report that this area has not been cleansed?


The robot will not develop a report for any rooms that have not been cleansed. We recommend the user maintaining a record of the proposed disinfection ‘route’ and those completed so any un-sanitised spaces can be returned to when accessible. The robot notifies the user whenever new elements such as new furniture is placed in a previously mapped room. In such cases a new room map is required for a continuous effective disinfection run.




In relation to the mobility of the robots, what flooring surfaces and incline can they navigate?


The robot can navigate most underfoot surfaces. The Sol model can handle 5-7% incline at a reduced speed.




Is the app downloadable on any iPad/Smart phone?


Authorised users can log in through a web portal using a tablet, smartphone or any other device equipped with wi-fi and a browser. The robot has its own wi-fi hotspot which the user connects to. No App download is necessary.




How is each robot activated?


The robots can only be activated using a username and authorised password. Every user has an individual password assigned to them. Remote assistance to recover any passwords is also provided.




Do lamps need a power supply to work?


Yes: a germicide lamp is part of a system and the system cannot be fully defined and optimized unless the lamp and reactor combination are determined. It is the interaction between lamp and reactor that is the real determining factor in the system's performance.




Is there a ‘fast clean’ setting?


The robots benefit from a quick mode or a personal settings mode according to needs, especially for a fast turnaround of space. However, the efficacy of the robots UV-C light may be affected through adjusting the time away from what is recommended.




Is there any indication of time/money saved/efficiency of virus elimination when using robots versus general cleaning?


The only cost of using the UV-C disinfection robots is energy and lamp replacement (approximately every 16,000 hours). Disinfection is carried out using Oxygen in the air which is abundant, free of charge and environmentally friendly. There is no purchase or transportation of harmful chemicals as with traditional cleaning/disinfection and the consistency of sanitisation is far higher using UV-C with Ozone that from an individual cleaner whose standard can differ from one and the other and from day to day.




What cleaning is recommended (if any) prior to using a UV-C disinfection robot?


Disinfection does not replace cleaning: dust, dirt and debris must be removed first. We would recommend using the UV-C disinfection robot as a final step in the cleaning process and in addition to regular disinfection of surfaces and spaces where possible.




How long does disinfection last?


After disinfection, the room will remain very low microbial load until new pathogens enter the room from a visitor. If properly cleaned and disinfected, the decontamination procedure does not need to be repeated until new ‘contamination’ has occurred i.e. room occupied by new visitor.




What is the right position for the UV-C robot?


The UV-C dose received in a room normally equipped after decontamination with a mobile unit that emits UV-C varies depending on the distance between the light source and the irradiated area and any object between those shadows. It is necessary to ensure that an adequate dose has been received in shaded and/or critical areas. Disposable indicators can help ensure that an adequate dose has been received.

As the distance from the lamp increases, the effectiveness against microorganisms decreases drastically, requiring a multiple placement in the room to achieve even partial disinfection.

Evolve Raybotix robots work via an automated, remote-managed system that self-regulates based on the size and dynamics of a room's contents to provide the right dose of UV-C light. Our technology uses the tool to measure UV-C light in a combined way that is diverted to shaded and indirect areas for terminal disinfection. When energy is diverted around the room, shadowed areas are reached and pathogens are eliminated ensuring a complete disinfection result, each time.




To be effective, how close do they need to be to the surface?


Exposure of the germicide ultraviolet is the product of time and intensity. High intensity for a short period and low intensity over a long period are basically the same in lethal action on bacteria. The law of the inverse square applies to the germicide ultraviolet as well as to light: the killing power decreases as the distance from the lamps increases. The average bacterium will be killed in ten seconds at a distance of six inches from the lamp.





Maintenance

 
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What is UV-C light?


Ultraviolet light belongs to the electromagnetic spectrum with a wavelength of between 200 and 400 nm (nanometres), which is shorter than that of visible light, but longer than X-rays. All rays and UV bands are invisible to the human eye.

The UV spectrum can be divided into the following bands:

  • UV-A (long waves; 400 – 315 nm) Applications: black lights, skin tanning, hardening with ink/resin.
  • UV-B (average waves; 315 – 280 nm): Applications: psoriasis therapy, it can cause sunburn, skin cancers.
  • UV-C (short waves; 280 – 200nm): Applications: Effective as a germicidal agent and pathogen disinfectant.
  • UV-V (less than 200 nm): Applications: Produces ozone by recombining oxygen atoms in the air.
All of the above wavelengths of UV light are emitted by the sun, but only the longest wavelengths, UV-A and UV-B reach the earth. UV-C rays, which are the shortest wavelength but with the highest energy are blocked by the ozone layer.




How does UV-C destroy harmful microorganisms?


Because UV-C rays are blocked by the ozone layer, microorganisms have not developed a natural defence against UV-C energy. When the DNA of a microorganism absorbs UV-C energy, molecular instability occurs, resulting in an abortion of the DNA sequence. This renders the cell unable to grow or reproduce. Without the ability to reproduce, the cell cannot infect and dies quickly.

The application of UV-C energy to deactivate microorganisms is known as germicide radiation or UV-GI. It has been used for this purpose since the early 1900s. Artificial UV-C energy is produced in germicide ultraviolet lamps that produce UV radiation by ionizing low-pressure mercury vapor. These lamps are similar to typical fluorescent lamps for home use, but do not have the phosphorescent coating that transmits soft white light. Most commercial UV-C lamps are low-pressure mercury lamps that emit UV energy at 253.7 nm, which is an ideal wavelength for disrupting the DNA of microorganisms.


UV-C lamps and devices are increasingly being used around the world in various configurations and applications to disinfect water, air, and surfaces.

The amount of UV-C energy required to inactivate a given microorganism is measured by dose, which is determined by a combination of radiation energy and exposure time. A key difference between surface deactivation and deactivation of microorganisms in air is exposure time. The time exposure in the UV field for microorganisms in the air is of the order of seconds and would require a much higher UV-C dose than that used for surface application.

Scientists determined the rate at which various microbial populations decrease due to exposure to biocide factors such as UV-C irradiation. Organisms differ in their susceptibility to UV-C inactivation; In general, viruses are the most sensitive to UV-C rays followed by bacteria with mould and fungal spores that are the least sensitive.

UV-C irradiation also obeys the inverse-square law of light, where the intensity at a given point is inversely proportional to the square of its distance from the light source.

Based on mathematical modelling, engineers developed proprietary and third-party computer modelling programs to estimate decommissioning rates for target microorganisms and then designed UV-C systems that will efficiently and effectively disinfect the air, surface or water according to the situation of interest




Is the use of UV-C safe?


Ultraviolet germicide irradiation used for the disinfection of water, air and surface is a biocide for microorganisms and extremely effective in deactivating harmful bacteria and viruses. The application of UV-C in the Evolve Raybotix Robots has been designed with maximum safety in mind – with an automatic abort function if movement is detected whilst in operation. Excessive direct UV exposure (no barrier present) can cause some risk to human health – for example eye damage in the form of keratitis photos and conjunctivitis. These symptoms usually appear within 6-12 hours of UV exposure and resolve within 24-48 hours. Direct prolonged exposure to ultraviolet radiation can also affect the skin and cause erythema (skin redness) much like when exposed to the sun for long periods. Most UV-C rays are reflected and absorbed by the outer dead layer of human skin, thus minimizing UV-C rays transmitted through the epidermal layer.

Appropriate personal protective equipment (PPE such as Safety Specs and UV Protective Clothing) is recommended when staff may be exposed directly to UV radiation.




How do UV-C rays disinfect?


UV-C germicide systems artificially generate a wavelength of 254 nm of light that destroys the DNA of microorganisms including viruses, bacteria and mould. Once deactivated, these microorganisms are no longer able to reproduce and grow on surfaces. In addition to disinfection of surfaces, UV-C also helps improve indoor air quality through compound breakdown and offers a more energy efficient sanitisation process than traditional methods which include use of toxic/hazardous/irritant chemicals.




Is the UV-C system effective?


Yes, scientific and anecdotal references are abounding in the effectiveness of UV-C in both literature and field application reports. Government reports, NIOSH, OSHA, CDC, GSA, EPA are the most notable. The science in the public forum from the University of Cincinnati, the University of Tulsa, the University of Colorado, and McGill University (Canada) are some examples. UV-C is used worldwide and well recognised for its disinfection properties, low energy/cost, and low H&S risk.




Does UV-C light alone kill 99.9% of bacteria? What additional assurances does the Ozone feature offer?


UV-C rays are effective where there is direct radiation onto space and surfaces. The emission of Ozone enables disinfection of shadowed areas and blind spots. Effectively all areas exposed to air in the exposed room will be disinfected with the Ozone oxidation action.




If UV-C rays are not visible, what is the blue light emitted by the lamp?


UV-C is the invisible part of the light spectrum. The blue colour comes from the inert gas inside the UV-C bulb. The light bulb can be turned on (and blue) but does not produce UV-C energy.




Does the UV-C device produce chemicals or by-products?


No, however, there may be a particular odour that is created due to the rupture of volatile organic compounds present in the air.




What does UV "C" or UV "GI" mean??


The letters "UV" refer to the spectrum of magnetic wavelengths known as ultraviolet light. This spectrum is most often divided into four categories: vacuum, short waves, medium waves and long waves 'or UVV, UV-C, UVB and UVA. UV-C is the most germicidal frequency and the term UVGI refers to "ultraviolet germicide irradiation" used by federal agencies such as OSHA, NIOSH, GSA, EPA and CDC when referring directly to UV-C.




Do UV-C lamps produce ozone?


UV-C lamps do not produce Ozone. UV-V lamps can produce Ozone. The UV-C provides exceptional air conditioning, very much like the sunshine outdoors. UV-C fixtures are a component for air conditioning that is added to other parts of the system. These include filters, coil, heating core, fan, shutters, humidifiers, etc. All are designed to provide a specific function in the work of air treatment for occupied spaces.




If I can't see UV-C energy, what do I see?


About 90% of the energy generated by a UV-C lamp is UV-C energy, the rest is visible light (blue shades) and a small amount of infrared (heat). Given the brightness of UV-C lamps, that 3-4% of visible light gives an idea of the amount of UV-C energy produced by a lamp.




Can UV-C rays kill dust mites?


There is no evidence that a UV-C dose suitable for a given killing of microbes has any effect on dust mites. Very high UV-C energy or long-term exposure to UV-C rays should disrupt some of the mite's biological functions, which can lead to death.




How is a UV-C system sized?


The Evolve Raybotix UV-C disinfection robots use proprietary software to accurately size a UV-C system for an application. The software model takes into account various parameters such as the type of microorganism(s), the size of the plenum/area or any cavities present, the air flow, the reflectivity of the walls, the temperature and humidity.




How long does UV-C take to kill microorganisms?


The UV-C dose required to deactivate a specific organism depends on the type of target microorganism, the UV-C intensity applied and the time of exposure to UV-C. The Evolve Raybotix UV-C disinfection robots have a large in-built database of dose values required to deactivate various bacteria, viruses and mould.




Do shading or shadows in the room affect the effectiveness of the UV-C robot?


Studies in the literature show that the concentration of pathogens, organic load and shading from the direct radiation field have not reduced the effectiveness of the robots. However, it is recommended that they are positioned to operate in multiple locations in a room to maximize the number of surfaces that are directly exposed to the UV-C light.




What is the effectiveness of UV-C disinfection robots against endospores such as C. diff and bacillus strains?


The UV-C intensity of the robots allows the endospores to be deactivated in as little as 5 minutes. This has been demonstrated in laboratory studies, studies on the hospital environment and validated in studies on outcomes showing reductions in C. diff rates reported by different hospitals using the same technologies.




Do all UV-C lamps contain mercury to be germicide? Do all UV-C lamps produce an ozone smell?


Most UV lamps used for UV disinfection contain mercury. In the case of low-pressure lamps, there are only a few milligrams of mercury. In the case of medium-pressure lamps, which have a much higher power, there are a few grams.
Low- and medium-pressure lamps generate ozone if they have a very pure (synthetic) quartz casing, which allows the mercury emission of 185 nm to enter the air. This UV light is absorbed by oxygen into the air to generate ozone. Most UV lamps are made with a quartz shape that contains impurities that completely absorb the emission of 185 nm, so as not to produce ozone.




How do I calculate ultraviolet radiation?


The intensity of UV radiation is measured in units of milliwatts per square centimetre (mW/cm2) which is the energy per square centimetre received per second. In addition, it is measured in units of millijoules per square centimetre (mJ/cm2), which is the energy received per unit of surface in a given time.




Can germicide UV-C penetrate surfaces or substances?


No – UV-C germicide sterilizes only what it comes into contact with.




How do you determine the area that will cover a germicide UV-C lamp?


This is determined by the power of the lamp. Example: A 15-watt lamp will cover about 10m2. Higher powered lamps mean a higher area of effectiveness.




How much intensity of UV-C do I need to kill certain organisms?


Exposure of the germicide UV-C ultraviolet is the product of time and intensity. High intensity for a short period and low intensity over a long period are basically the same in lethal action on bacteria. The law of the inverse square applies to the germicide ultraviolet as well as to light: the killing power decreases as the distance from the lamps increases. The average bacterium will be killed in ten seconds at a distance of six inches from the lamp.




Will germicide UV-C take care of mould?


Yes. UV-C germicide lamps will kill up to 99.9% mould and help prevent future mould growth.




Do germicide UV-C amps kill viruses?


Yes, germicide UV-C lamps kill up to 99.9% of most viruses, bacteria dispersed in the air and mould spores.





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