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.
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
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.
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.
Ozone Explained
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
Is the battery replaceable/interchangeable? i.e. Can you charge the battery separately and use a fully charged one immediately so there is no down time of the robot?
Yes, the battery is replaceable and can be charged separately whilst a reserve battery is used to minimise down time. The robots are also now fitted with a plug so the system can work directly from the electricity supply when connected whilst also charging.
How frequently do the UV-C lamps need to be replaced?
Approximately every 16,000 hours. The lamps can work long after their useful life, but at reduced intensity as the filaments of the lamp wear out over time.
Should UV-C lamps be cleaned?
UV-C lamps should be checked periodically (about every three months) and cleaned with a microfibre cloth.
How can I dispose of UV lamps?
UV lamps should be treated like fluorescent lamps and in accordance with each country’s environmental regulations.
Does the Ozone mechanism need to be replaced?
No. This feature is UV lamp dependent hence follows the same UV lamp replacement requirements.
Operations
Is the battery replaceable/interchangeable? i.e. Can you charge the battery separately and use a fully charged one immediately so there is no down time of the robot?
Yes, the battery is replaceable and can be charged separately whilst a reserve battery is used to minimise down time. The robots are also now fitted with a plug so the system can work directly from the electricity supply when connected whilst also charging.
How frequently do the UV-C lamps need to be replaced?
Approximately every 16,000 hours. The lamps can work long after their useful life, but at reduced intensity as the filaments of the lamp wear out over time.
Should UV-C lamps be cleaned?
UV-C lamps should be checked periodically (about every three months) and cleaned with a microfibre cloth.
How can I dispose of UV lamps?
UV lamps should be treated like fluorescent lamps and in accordance with each country’s environmental regulations.
Does the Ozone mechanism need to be replaced?
No. This feature is UV lamp dependent hence follows the same UV lamp replacement requirements.
Maintenance
What training is recommended/required for use of the robots?
It is essential for any operator to undertake the online/in-person training course to familiarise themselves with the features, functionality and requirements of the robots as well as understand the standard operational guidance. There will also be a requirement for onsite training for use of the Sol and a ticketing system set up via the website for any queries. Online tutorials will also be available for refresher training and specific function instructions.
Training