UV disinfection is making significant strides in industry and medicine, paving the way for success. Recognized as a cost-effective and dependable process, it is gaining popularity at an increasing rate. Moreover, ultraviolet radiation-based disinfection has secured a crucial position in our daily lives, even if its presence may not be immediately apparent.
The utilization of UVC radiation serves as the basis for UV disinfection. While this form of radiation naturally exists within sunlight, it gets entirely filtered out by the atmosphere surrounding our planet. As a result, any occurrence of UVC radiation in our surroundings always originates from man-made sources.
Curiosity arises regarding how exactly UVC disinfection operates, where it can be applied effectively while ensuring safety precautions are met. Rest assured that all your inquiries about UV disinfection will find answers on this very page.
- What is UV radiation?
- How does disinfection using UV disinfection work? What are its advantages?
- What dose is required for UV disinfection?
- What areas of application are there for disinfection with UVC radiation?
- Possible risks of UVC radiation
- What safety measures must be observed during UV disinfection?
- Which forms of UV disinfection are considered safe?
- UV disinfection: Sustainable hygiene technology of the future
What is UV radiation?
Ultraviolet radiation is electromagnetic waves with a wavelength of 100 to 380 nm or a frequency of over 789 THz. The energy of a single quantum of light is around 3.26 eV. Ultraviolet radiation is not visible, but it belongs to the group of optical wavelengths, which is why the term “UV light” is often used – but strictly speaking this is not entirely correct.
UV radiation is divided into three different types: UV-A, UV-B and UV-C. Each type has different wavelength ranges and physical properties – the energy of the light quanta is inversely proportional to the wavelength: the shorter the wavelength, the more energetic the radiation.
|Immediate, short tanning; skin ageing and wrinkling, practically no erythema (sunburn-inducing) effect
|Tanning, photochemical reactions, luminescence, ink curing, lacquer drying, light therapy, forensics, effect light, …
|Long-term tanning; forms a protective layer on the skin; penetrates into deeper skin layers, high risk of skin cancer, has a strong erythema effect -> sunburn
|Light therapy / tanning, photochemical reactions, luminescence, ink curing, paint drying, …
|very short-wave, does not reach the earth’s surface, absorption by the uppermost layers of the earth’s atmosphere. Has a very strong decontaminating effect. Very strong erythemal effect
|Physical sterilization technology, photochemical reactions, luminescence, …
|VUV (Vakuum UV oder Deep-UV)
|very short-wave, ozone-forming by disoccupation of atmospheric oxygen from O² to O³ (ozone). Only measurable in a vacuum. Measurable up to 150 nm in a nitrogen environment (<15 ppm oxygen content)
|Surface cleaning, photooxidation, surface activation, ozone generation, …
At sufficiently high intensities, UV radiation can trigger chemical reactions and cause biological damage. This makes it useful for applications such as disinfection, where the ability of UV radiation to damage the DNA and RNA of microorganisms is used to inactivate them and prevent them from reproducing.
UV radiation has many applications from medicine to industry, but one of its most notable applications is disinfection. The ability of UV radiation to kill harmful microorganisms makes it an effective tool to sterilize surfaces, water and air.
How does UV disinfection work? What are its advantages?
All microorganisms contain nucleic acid in the form of DNA and RNA, which contains the genetic information. The ultraviolet radiation energy is absorbed by the nucleic acids, which damages the genetic information and reproduction apparatus of the microorganisms within fractions of a second and thus inactivates germs – this happens, among other things, via a frequently occurring “dimer bond” of the thymine building blocks.
The advantage: Conventional measures for disinfection or germ control such as alcohol or antibiotics always carry the risk of resistance developing – the MRSA problem therefore poses a serious problem for many medical facilities.
UV disinfection, on the other hand, eliminates this risk – in fact, most pathogenic germs are particularly sensitive to UV radiation.
Whether E. coli bacteria, faecal germs, TBC, SARS, anthrax or legionella: UV disinfection is effective against all forms of microorganisms. The prerequisite is a sufficient UV dose – and the appropriate device development.
What dose is required for UV disinfection?
The correct irradiation dose is crucial for effective UV disinfection. This is calculated as follows:
Every UV radiation source has an electrical power consumption, part of which is emitted in the UV-C range. 90% of the radiation emitted in the UV-C range is generated at 254 nm, the effective wavelength for disinfection. This is referred to as the radiant power. The radiant power is therefore the energy emitted by the emitter per unit of time. The irradiance or intensity (µW or mW) is the radiant power per unit area (cm²). The optimum utilization of the emitter installed in the device and the distance to the object to be disinfected are decisive for its level.
Multiplying the irradiance/intensity by the time (s) gives the UV dose/irradiation dose: UV dose (mWs/cm²) = intensity (mW/cm²) x time (s)
The disinfecting effect increases in proportion to the radiation power and irradiation time.
Different microorganisms require different amounts of UV radiation to be effectively killed. This value is often referred to as the lethal dose: The lethal dose is the amount of UV-C radiation required to render a specific microorganism 99.9% harmless.
What areas of application are there for disinfection with UVC radiation?
The ability of UV-C radiation to inactivate microorganisms makes it ideal for use in a variety of applications, including:
Water disinfection: UV disinfection is used in water treatment plants to remove harmful microorganisms from drinking water using waterproof UVC modules.
Air disinfection: UV-C devices are used in hospitals and other healthcare facilities to clean the air of infectious aerosols. This prevents the spread of diseases and the development of resistance.
Surface disinfection: In areas such as medicine or food production, UV disinfection can be used to disinfect surfaces and materials and to extend the shelf life of food.
|Area of application
(of solvent-free paints, varnishes, adhesives and potting compounds)
(of air, water and surfaces)
(of organic pollutants in air and water)
(for artificial aging of materials for safety and aesthetic reasons)
|Medical application / light therapy
Potential risks of UVC radiation
The International Agency for Research on Cancer classifies all types of UV radiation – whether UVA, UVB or UVC – as carcinogenic to humans, regardless of their natural or artificial origin. These types of radiation pose both acute and chronic health risks: exposure to UVC can lead to inflammation of the cornea and conjunctiva (photokeratitis, photoconjunctivitis) and the skin (erythema) and damage the genetic material of the cells. This damage to the genetic material enables the inactivation of microorganisms in UV disinfection, but can cause cancer in humans in the long term. The Federal Office for Radiation Protection therefore expressly warns against using UVC disinfection devices to disinfect living organisms. Safe and responsible use of this technology is essential.
What safety measures must be observed during UV disinfection?
UV-C radiation is extremely effective when it comes to disinfecting things. However, it can also be harmful to humans if not handled correctly. Therefore, some simple safety measures are absolutely essential. If you have any questions about safe use, we will be happy to advise you.
|UV radiation is dangerous for eyes and skin. UV radiation sources may therefore only be operated under appropriate personal protection measures. This does not apply to closed devices from which no UV radiation can escape (water disinfection systems, air disinfection systems based on circulating air, etc.).
|Protection from UV
|UV radiation at 254 nm (UV-C) can be shielded by normal window glass (borosilicate, Duran, etc.), transparent plastic such as Makrolon®, Plexiglas® and practically all opaque materials. The use of colored material is recommended in order to reduce the potentially disturbing glare effect. Further information on UV filters can be found in the standard “EN 170 – Personal eye protection”. Quartz glass is permeable to UV-C radiation and must not be used as protective glass for personal protection.
|Installation / Operation
|Changeover circuits, information signs or forced shutdowns must be installed at the responsibility and discretion of the operator. If individual components are put into operation for integration into systems and devices or sample deliveries, the operator is responsible for observing the relevant electrotechnical regulations. Only trained and qualified personnel with the appropriate training should put the components into operation.
|Objects can become discolored after long and intensive UV exposure. We recommend the use of UV-resistant materials. When using ozone-forming radiation sources, please note that ozone has a strong oxidative effect.
|When using ozone-forming UV radiation sources, the MAK value (MAK = maximum workplace concentration) of 0.1 ppm must be observed. For test setups, it is recommended to use a suitable area with air extraction.
|Low-pressure lamps have a light tube temperature of approx. 40°C during operation, similar to a fluorescent lamp in lighting technology. UV radiation sources with indium amalgam doping become approx. 90°C-100°C hot on the surface of the light tube (medium-pressure radiation sources approx. 850°C-950°C). These radiation sources must be regarded as potential ignition sources in the event of contact with highly flammable substances. Furthermore, the radiation source must cool down sufficiently before it is touched. To ensure that the radiation source ignites after being switched off, indium-amalgam doped emitters should cool down for approx. 2-5 minutes (medium-pressure emitters approx. 5-15 minutes). Cooling down is not necessary for simple low-pressure emitters.
Which forms of UV disinfection are considered safe?
Although UVC radiation is potentially harmful to humans, there are various systems and processes that use it safely for UV disinfection. If the radiation source is in a closed housing or sufficiently shielded, there is no risk to people present in terms of radiation protection. An example of this are UVC sources that are installed inside a closed system – for example disinfection modules for conveyor belts or escalators as well as systems for room air disinfection with a shielded radiation source inside the system. Applications in which there are no people in the room (for example, outside of operating hours) also pose no risk.
We will be happy to advise you on your options at the planned location. You can also find information on occupational health and safety requirements and permissible radiation levels at the Federal Institute for Occupational Safety and Health (BAuA) and the relevant employers’ liability insurance associations.
UV disinfection: Sustainable hygiene technology of the future
The use of UVC radiation for UV disinfection is a highly effective technology that has the potential to revolutionize our approach and methods in areas such as water treatment, air purification, food safety and infection control. Its ability to kill a wide range of microorganisms quickly and efficiently, without using harmful chemicals, makes this method extremely attractive for various applications.
Our team at Peschl Ultraviolet has many years of experience in the development and production of versatile system solutions for UV disinfection. We will be very pleased to answer any questions you may have on this subject. Take advantage of our consultation service to find out more about the possible applications of our safe, robust and sustainable UVC disinfection modules.