The UV-C light with 100 to 280 nanometres is the shortest wavelength range of the ultraviolet light. With intact ozone layer however this range of ultraviolet light gets filtered from the solar ray spectrum before impinging upon earth’s surface.
As contrasted to UV-B radiation, which particularly deeply penetrates the epidermis, a causal relation of dermal cancer owing to intensive UV-C radiation could not yet be scientifically proven.
The principle of operation
The extreme high-energy UV-C radiation prompts a photochemical reaction. The wavelengths with 253, 7 nm get absorbed by the cell nucleic acids and, depending on the radiation dosage, lead to a killing, resp. impairment of germs and fungal spores. Hence the UV-C radiation sees use in the targeted impairment or killing of micro-organisms (like e.g. germs, viruses, yeasts and mildew).
The dose principle
This refers to the basic influence of the factors time and power. The product of radiation time and radiation intensity is indicated as mWs/cm².
While microorganisms with a simple structure have a high sensitivity to UV-C light, meaning they can be deactivated easily with a low dosage, significantly higher energy levels are required to eliminate fungi and spores. Therefore, the effectiveness of UV-C for deactivating microorganisms is always directly related to the applied dosage.
The disinfection technology
The main spectrum of the STERILSSYSTEMS UV-C lamp is on the range of 254 or of 185 nm. Beneath 240 nm of wavelength the ultraviolet light generates ozone from oxygen. Especially for the disinfection in the food sector only those emitters are applied that don’t create ozone. An ozone formation during the disinfection process gets prevented with STERILSYSTEMS UV-C germicidal lamps by use of special materials.
An important advantage of the physical UV-C disinfection is that it cannot cause any resistance. The UV disinfection even works out, when germs already attained a resistance against conventional disinfection methods like alcohol, antibiotics etc. …
The UV-C disinfection works out with all kind of micro-organisms, no matter whether it concerned the frequently arising E. coli bacteria, SARS, legionella or mould. A sufficient UV dose, many years of application know-how and the necessary device technology are the basis for the desired success. The number of scientific proofs straight continued to increase in the last years.
Thus e.g. in the drinking water ordinance UV-C water disinfection reactors are listed as one of the methods of disinfection. UV water disinfection units get certified to DVGW and Austrian Standard. For air handling systems the VDI 6022 applies and regulates the usage of UV-C radiation for safe air disinfection. In a sufficient dose UV-C rays cause skin redness (erythema) and ophthalmitis, well-known also as arc eye. That’s why the limit value must not be exceeded.
UV-C radiation with 254 nm may be shielded by normal window glass, transparent plastics like Makrolone® and practically all opaque materials. For further information concerning UV filters please consider the norm „EN 170 - Personal eye protection“. Quartz glass is permeable for UV-C radiation and must not be applied for personal protection.