Ultraviolet sanitizing light, a precious resource

Ultraviolet sanitizing light, a precious resource

Ultraviolet radiation can eliminate viruses and bacteria that settle in our indoor environments and surfaces. Recent studies have proven that UV radiation is also effective against the new coronavirus. It is an ecological and easy means of disinfection, but that requires the support of an expert installer and can be used only in the absence of people.

Ultraviolet (UV) radiation can neutralize the new coronavirus in just a few seconds. The news comes from an Italian research that involved scientists from different disciplines. Physicists, biologists and medical physicians from the Italian National Institute for Astrophysics (INAF), the University of Milan and the Italian Cancer Institute of Milan have experimented, for the first time, the effects of the direct radiation of UV-C (with wavelength of 254 nm) on the SARS-CoV-2 virus, responsible for the pandemic that is currently being faced globally.

“We exposed different concentrations of viruses to UV light – said Mara Biasin, Professor of Applied Biology at the University of Milan – and we found that a relatively small dose (3.7 mJ/cm2), equivalent to that delivered for just a few seconds by a UV-C lamp placed at a few centimetres from the target, is sufficient to inactivate and inhibit the reproduction of the virus”.

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The sanitizing power of UV light

The ability of UV-C to neutralize viruses and bacteria has been known for decades. Ultraviolet radiation interferes with the DNA of microorganisms and prevents their replication. For the first time ever, this new research has proven its efficacy also against the new coronavirus.

UV devices have been used for many years in several sectors to sterilize medical instrumentation, food containers, air conditioners and for water purification. In its recommendations for the prevention of coronavirus contagion, the Italian Healthcare Institute included the “treatment with ultraviolet radiation” among the means to sanitize surfaces and indoor environments.

UV lamps can be easily integrated into normal lighting systems. It is an easy-to-use and ecological means of disinfection because it is based on a physical method and does not require the use of chemicals that can harm the environment.

The technology, however, is not without risks. UV-C rays, which in nature are found in very small doses thanks to the protective shielding of Earth’s atmosphere, may cause damage to the eyes and skin, which can even be permanent if exposed to high levels. Moreover, UV-C radiation may also damage some materials, such as plastics, fabrics and paints, making their colours fade or turn yellow.

Therefore, a UV sanitizing lighting system entails a careful assessment of the risks involved and must be developed by an expert installer with reliable fixtures.

This topic has been discussed by several trade associations starting from the Global Lighting Association (GLA) which gathers the world’s lighting manufacturers. To this end, GLA published their UV-C safety guidelines containing recommendations on the safe use of UV-C lamps.

The Italian Association of Lighting Manufacturers (ASSIL), too, recently published a document on UV lamps for indoor environments.


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Effectiveness, the conditions for an indoor environment to be sanitized

The first thing to consider when using UV lamps to sanitize an environment is effectiveness. It is important for the system to guarantee the performance for which it was designed, namely the inactivation of viruses and bacteria, and ensure that the environment is safe and without risks of contagion. According to the instructions of ASSIL, to be sure of the effectiveness of UV lamps on spores, germs, bacteria and viruses, the system must be designed to offer the correct combination of four factors: radiated power, exposure time, distance, emission spectrum.

Basically, the system must emit enough radiation of the required spectrum at the right distance and for the time necessary to inactivate microorganisms.

For this reason, a UV sensitization system must be entrusted to an expert installer who has the necessary knowledge to create all these conditions.

Safety, to be used only in the absence of people

As for safety, the first and most important thing to consider is that fixtures emitting UV-C into the environment must be used exclusively in the absence of people. To this end, timers and presence sensors can help to switch off the lamps at pre-programmed times or only when no one is in the room. ASSIL points out that timers and sensors cannot guarantee perfect operation in case of electrical failures and so even with these devices, warning signs and adequate information about sanitization times and modalities should be used.

Moreover, this type of system cannot be used on all surfaces. The exposure to UV-C radiation can alter materials like plastic. In the medium-long terms they can also alter the colour of fabrics, paintings or precious surfaces, so it is necessary to consider carefully which objects to irradiate in order to prevent damage that can even be permanent.

Moreover, ultraviolet radiation can interact with airborne chemical substances, while optical radiation with wavelengths below 240 nm can produce ozone that may be harmful for humans.

A precious resource against the COVID-19 pandemic

Apart from an adequate assessment of the risks and the appointment of an expert installer capable of guaranteeing its effectiveness, the use of UV lamps can become a precious resource for the sanitization of indoor environments, and therefore for the fight against the coronavirus pandemic.

We can easily imagine the multiple applications in the workplace, as well as in schools, hospitals, hotels, and wherever there is the need to guarantee the safety of highly frequented environments.

Longer exposure to efficient UV-A fixtures can be activated at night or during the holidays while UV-C, with a faster sanitization time, can be activated during lunch breaks or between classes. Similarly, this technology can be used in hospital waiting rooms, shopping malls and hotels, on the condition that sanitization occurs in the complete absence of people.

So, as we wait for a vaccine and effective therapies against the new coronavirus, we can use UV light as a precious ally to limit the spreading of the disease.

  • Posted by Redazione
  • On July 24, 2020
Tags: Ultraviolet sanitizing light


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