Germicidal Ultraviolet Rays (UV-C)


Ultraviolet rays are part of light in a broad sense (electromagnetic waves) that are divided in three main wavelength ranges (measured in nanometers; nm):

  • Ultra-violet rays (UV) 100-400 nm
  • Visible rays (light) 400-700 nm
  • Infra-red rays (IR) 700-800.000 nm

The UV rays are invisible and are in turn classified in three bands:

  • UV-A (315-400 nm) with tanning properties;
  • UV-B (280-315 nm) with therapeutic properties and synthesis of vitamin “D”;
  • UV-C (100-280 nm) with germicidal properties

In particular, UV-C rays have a strong germicidal effect and present the greatest efficiency in correspondence with the wavelength of 253.7 nm. The UV rays are contained, for example, also in sunlight and the beneficial germicidal effect of sunlight has been known since antiquity. UV radiation must not be confused with ionizing radiation (X-rays and gamma rays that have wavelengths below 10 nm) which, in contrast, change the atomic structure of the materials.

The germicidal effects of the UV-C radiation extend to bacteria, viruses, spores, fungi, mold and acari (including mites and ticks); this is due in particular to the destructive effect exercised by the UV-C radiation on their DNA; this contributes to damaging their reproduction system, impeding their growth and multiplication.


The LIGHT PROGRESS germicidal tubes consist of a special material (the purest quartz), transparent to UV-C radiation, while the classic glass used for producing fluorescent lights does not allow passage of radiation of wavelengths under 350nm.
Mercury vapors are enclosed inside; undergoing an electrical charge, they emit radiation, the spectral distribution of which is shown in the figure. Ninety percent of the energy emitted is on 253.7 nm wavelength, the value with which the mercury atom resonates; this frequency has the highest germicidal value.


An important advantage of this physical disinfection process is in the fact that, bacteria viruses, spores fungi, mold and acari, are all sensitive to UV-C radiation.
Microbes cannot acquire resistance to UV rays, something that takes place, in contrast, with chemical disinfectants.
UV rays are ecological. Environmental pollution is inevitable with the use of chemical disinfectants. Furthermore, there is the danger of serious hazards from direct inhalation of vapors or ingestion of food products polluted from possible contact with the chemical disinfectants themselves.
With the use of LIGHT PROGRESS devices, running costs are minimal; we can confirm that a “LIGHT PROGRESS” UV-C installation requires no maintenance, except for normal replacement of tubes. The cost/benefit ratio can be considered excellent; the devices are powerful and of significant duration. Therefore, the destruction of germs through the UV, in comparison (or in interaction) to other systems, is low cost and highly effective.

Do you want further information? Check our FAQs!