UV-C can deactivate the virus that causes COVID-19 – How safely to apply this technology for disinfection purpose?

As the world comes to terms with the first great global pandemic of our age, technology like UV-C disinfection lighting will play an ever more important part in our future.

There are three type of UV radiation found in sunlight. There’s UV-A and UV-B, which you may recognize from sunscreen labels. UV-A and UV-B cause sunburn and signs of skin ageing like wrinkles and age spots, and even skin cancer. We don’t come into contact with UV-C because it is filtered out by the ozone layer in the Earth’s atmosphere. The wavelength of UV-C light is shorter than the wavelength of the light we can see and it is most effective at inactivating viruses on or around 260-265nm, known as the ‘germicidal peak’. Signify’s UV-C lamps operate at 254nm, using ultraviolet light to inactivate microorganisms like viruses and bacteria, making them harmless to humans. All micro-organisms that have been tested so far for UV-C exposure were shown not to be resistant to UV-C light. This was also proven by the testing of Signify germicidal UV-C light at Boston University resulting in a reduction in the virus of 99% in 6 seconds.

Humans and animals should not be exposed to germicidal UV-C light at this wavelength as it can cause damage to their skin and eyes in a matter of minutes of exposure. By ensuring that the appropriate safeguards are put in place and that users and operators are well-instructed and trained, UV-C disinfection is a recognized and well-established means of disinfection.

Signify’s professional UV-C products are designed and intended to be used by trained professionals who take the appropriate safety precautions. There are also solutions in which UV-C radiation at 254nm is safe to use with people in the room. The upper air disinfection systems are designed to allow people to be present underneath them during their operation. These systems are installed high up in the room and disinfect air through natural convection as it passes through a well-controlled and narrow UV-C irradiated zone that remains close to the ceiling. This zone is at a height above where people are typically present. People can also be in a room when using our UV-C chambers to disinfect objects. Items are placed inside the chamber for treatment. The UV-C radiation is completely contained inside the chamber in the same way that microwaves are absorbed inside a microwave oven.

Where safety precautions are needed is during direct exposure of surfaces to a UV-C light source. This is the case, for example, with the disinfection of surfaces in an office or a bus. To prevent damage to eyes or skin resulting from direct exposure to UV-C light sources, no people or animals can be present during a UV-C surface disinfection cycle. That’s why surface disinfection cycles are typically run at night after all people have left the office or after the bus returns to the depot. To be on the safe side, extra levels of safety can be provided by sensors that can switch the UV-C light sources off if they detect people or animals. UV-C light with a shorter wavelength (in the range of 207 – 222nm) is sometimes known as Far UV-C. Far UV-C light can’t penetrate the cells of our skin, so it has potential to be used to disinfect areas where there are people.

The COVID-19 pandemic has accelerated the development and use of UV-C disinfection products across the globe. With that in mind, it’s essential that companies involved in the production and roll-out of germicidal UV-C lighting adhere to the highest safety standards. The Global Lighting Association has developed guidelines for manufacturers and users of UV-C disinfection products that focus on increasing the safety of products for their users. Signify’s UV-C products are developed and designed to meet the high standard set by this new guidance.

SIGNIFY INTERNATIONAL B.V. OGRANAK BEOGRAD

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