FAQs

Ultraviolet light is the non-visible portion of the electromagnetic spectrum with wavelengths  between 100 and 400 nm. The UV spectrum is further subdivided into UV-A (wavelengths of 400  to 315 nm), UV-B (315 to 280 nm), UV-C (280 to 200 nm) and vacuum UV (200 to 100 nm).

The UV-C wavelengths (also called germicidal wavelength) are the most effective for inactivating microorganisms with peak effectiveness near 265 nm.

Learn More >

Germicidal UV-C systems artificially generate a wavelength of 254 nm of light which destroys the DNA of microorganisms including viruses, bacteria and mold. Once deactivated, these microorganisms are no longer able to reproduce and grow on surfaces.

In general HVAC applications, UV-C is used to inactivate microorganisms and eliminate the organic build up on cooling coils and drain pans. In addition to improving the indoor air quality, this makes the cooling coil more energy efficient while eliminating the need to clean the cooling coil via traditional methods.

In sensitive and public environments, UV-C is not only used for coil and drain pan, but also for disinfecting the airstream of airborne viruses, bacteria and fungal spores.

UVDI uses proprietary software to precisely size a UV-C system for an application. The software model takes into account various parameters such as the type of microorganism(s), size of the plenum or duct cavity, the air flow rate, wall reflectivity, temperature and humidity.

The UV-C dose required to inactivate a specific organism depends on the type of the microorganism that is being targeted, the applied UV-C intensity and the time of exposure to UV-C. UVDI has an extensive database of dose values required to inactivate various bacteria, virus and molds.

Overexposure to UV-C can result in short term skin redness and eye irritation. UV-C does not cause any permanent damage to skin or eyes.

UV-C is the invisible part of the light spectrum. The blue color comes from the inert gas inside the UV-C bulb. The bulb can be lit (and blue) yet not produce any UV-C energy.

The output of the UV lamps can be measured using a UV-C radiometer. Effective of a UV system can be determined by visual inspection of coil and drain pans and microbial sampling. ASHRAE has developed test standards to evaluate the effectiveness of UV for coil and airstream applications.

UVDI recommends that the UV lamps should be replaced annually or after 9,000 hours of continuous use. Lamps can operate long after their useful life but at reduced intensity as the lamp filaments wear out over time.

UV lamps should be treated the same as fluorescent lamps and in accordance with local, state or federal regulations.