Living with the coronavirus is part of our lives in this "new normal". With this, hundreds of disinfecting solutions have proliferated, including UV radiation devices. In this context and before dozens of daily inquiries to CICAT, the Lighting Cluster has chosen to publish a guide to comprehensive technical safety standards for UVC devices.
It is four months of inflection since the State of Alarm was imposed in our country due to the high numbers of infected and deceased by Covid 19. After the urgency of acquiring protection material for health workers and the general population that was dedicated to Basic care services, another concern came. The disinfection of spaces and objects to return as soon as possible to a "new normal" and reactivate the country's economy. Along with a multitude of options, one of the safest and most effective according to scientific circles is disinfection by UV radiation
WHY UV DISINFECTION?
If we talk about ultraviolet disinfection we have to explain that radiation is classified by the length of its wave. The UV radiation it is invisible to the human eye and has a wavelength between 100 and 400nm (nanometers). It is divided into 3 subtypes: UVA (315-400nm), UVB (280-315nm) and UVC (100-280nm). The order of germicidal efficacy of UV is UVC> UVB> UVA.
UV radiation, and to a greater extent UVC, destroys the reproductive capacity of microorganisms due to photochemical changes. It is a widely known method of disinfection and suitable for various types of viruses, including SARS-CoV. The disinfection efficiency depends on several factors, such as the power of the radiation, the distance to the irradiated object, the areas unreachable by direct radiation, the presence of proteins or other elements that absorb UV, among other more specific factors.
For all these reasons, it is stressed that the use of UVC disinfection devices is a complementary method to traditional cleaning.
EFFECTS OF UV RADIATION ON LIVING BEINGS AND MATERIALS
The use of direct UV radiation devices in the presence of people, animals or plants is totally prohibited. The effects of UV radiation on the skin and eyes depend on the exposure time and the amount of radiation received.
UV radiation has different effects on the materials it is exposed to. These vary depending on: the nature of the material and the temperature and humidity conditions.
Ceramics are generally less susceptible to UV damage. In the event that it affects, it can create cracks in the structure of the material. Although the degradation of this type of materials can come more from the pigmentation and tints that decorate the ceramics than from the material itself.
The most resistant material and unaffected by UV radiation is metal. This is because, due to its structure, free electrons are capable of absorbing the energy of the photons.
RADIATION ON PLASTICS
Now, plastics are the most affected by UV radiation exposure, causing yellowing and cracking. Although this may seem to be very harmful to plastics, it should be noted that, for many years ago, UV protection layers have been incorporated into plastic products to mitigate the damage that exposure to UV radiation can cause.
In addition, the progressive yellowing that can be observed in the early stages of radiation, only affects the last few microns of the plastic part, while the material inside is in perfect condition and will not affect its functionality.
Currently, the most common source of use for the manufacture of UV disinfection devices is the low pressure mercury discharge lamp (9.000 hours of life). It emits a wavelength of 254nm. The value is not the one with the highest germicidal power (which would be between 260-265nm) but, in today's market, it is the closest source of light.
Low pressure discharge lamps achieve very noticeable germicidal results and do not generate ozone, due to their wavelength. The ozone generating UV lamps are emitting 185nm.
This data should be highlighted, given that ozone can be dangerous in the use of spaces where they can be occupied by people. Unlike UV, ozone can remain in the environment after the disinfection process has finished, not like UVC radiation, which, once deactivated, does not cause danger or harmful effects.
WHAT TO TAKE INTO ACCOUNT WHEN MAKING A UV EMISSION DEVICE?
Given the wide range of UV-C disinfection devices and solutions that have emerged on the market, much uncertainty has been generated about the quality of the product. Therefore, it is important to evaluate the UV source used by the device, as well as the materials of which it is made.
Low-pressure UVC mercury discharge lamps have some of their radiation in the visible spectrum, resulting in a bluish or cyan color when lit. Therefore, unlike LEDs, it is not necessary to include any warning element since it is visually visible when they are on.
When it comes to emission from tubes, the luminaire itself will be greatly affected by radiation because a large part of it will be emitted towards the luminaire, so a correct selection of materials and their protection is very important. Luminously, the materials do not reflect visible light in the same way as UVC radiation. This implies that the photometric curves will be different in each case and a different photometric study will be necessary for the design of the reflectors.
In the case of a portable luminaire, it should have a remote control, which allows the user to activate it from outside the room or area to be disinfected.
It is also important to install presence detectors that disable radiation if movement is detected in space.
HOW TO MEASURE UV RADIATION?
Once the installation is done, it must be verified that the wave emission is the one required to have the desired germicidal effect.
There are two families of teams, radiometers and radiometer spectra. Radiometers operate very similar to a luxmeter. It is a photometer that when the radiation reaches it is calibrated to receive a signal that is later shown on a display in the form of a number.
But we found a negative aspect in the use of radiometers and that is that it does not happen like luxometers that measure the entire visible range, but are only calibrated to measure narrow ranges of the spectrum. For example, in the following image we can see the peak at 254nm. Most UVC radiometers are calibrated with this lamp, so the radiometer will not fail. But if, on the contrary, we measured a led that was at 280nm instead of a discharge lamp, the radiometer would give a lower value than the real one.
The previous problem is not found with the radiometer spectra, because they measure the entire spectral panorama.
GOLDENSEA UV - QUALITY MANUFACTURER
The manufacturer Goldensea UV, leader in the lighting sector, has developed a complete range of UV-C disinfection devices. The ultraviolet light disinfection method C has positioned itself as one of the most reliable systems for all types of spaces, places and objects. At Stonex we are a national distributor of Goldensea UV products, offering a complete training in the use of the devices to avoid risks and uses.
STONEX - who we are
STONEX is dedicated to integrating professional lighting and control solutions. 40 years of experience in the professional lighting sector, more than 500 projects and the trust of more than 1.500 clients guarantee the professionalism of a team in constant training and development. Our know-how in the demanding world of professional lighting has allowed us to develop in transversal lines such as UV-C lighting, emergency lighting and mechanics in scenic spaces.
(You can find the full text of the “Technical guide for the use and installation of UV radiation” prepared by CICAT in this link).
Source of this article:
- La “Technical guide for the use and installation of UV radiation” prepared by CICAT
- Smart Lighting magazine webinar broadcast on your You Tube channel “Presentation of the« Technical Guide for the Use and Installation of UV Radiation »prepared by CICAT. Moderated by Mario Prieto (editor of the media) and participation of: Marc Balbé from ASSELUM, Carlos Salafranca from LUXIONA and Meritxell Humbert LEDS & COMPONENTS EXPERTS all of them belonging to the working group that CICAT formed for the purpose of preparing the document