Learn about UVGI light disinfection

for inactivating viruses from surfaces and indoor air

What it is, how it works and where it’s used

Although UVGI disinfection has been in use for decades, the COVID-19 pandemic created new interest for the possibility of killing the virus on surfaces and in indoor air. Gain a better understanding of this COVID fighting technology and how it works so you can be better informed about possible disinfection solutions for your application.

What is UVGI?

Ultraviolet germicidal irradiation (UVGI) is UV light in the UV-C wavelengths ranging from 200 to 280nm which is known to have a germicidal effect on organisms. According to the International Ultraviolet Association (IUVA), UVC light has been used for more than 40 years to disinfect drinking water, waste water, air, and surfaces against a wide range of human pathogens, mold, fungi, and bacteria.

UV disinfection devices and systems incorporate UV lamps whose output is in the UV-C range. Because these type of UV systems are used for disinfection, they are commonly referred to as UVGI devices. Manufacturers use different UV lamp technologies, such as arc lamps (similar to fluorescent) or LED, to create devices with different types of housings, reflectors, cooling, power supply and controls to suit different applications.

How does UVGI work?

UVC light at a wavelength of 254 nm is able to penetrate the structure of microorganisms such as viruses. Once absorbed by their DNA, the UV light disrupts replication rendering the virus, bacteria, etc. harmless – germs killed!

To be effective the UV light must be able to reach the virus. Any viruses hidden in crevices or behind obstructions will not be inactivated. For this reason, UVGI for surface disinfection is often used to supplement other cleaning procedures as a quick and easy way to reduce the germ load.

Factors to consider - Soluva UVGI disinfection of surfaces and indoor air

Other factors impacting effectiveness of UV light to inactivate microorganisms are:

  • intensity of the UV source – higher is better
  • distance between the UV source and the target – closer is better
  • duration of exposure – longer is better, but higher intensity enables shorter duration
  • extent to which the air or water environment interferes with UV energy - air temperature and humidity for example
  • susceptibility of a microbe to UV light – SARS-CoV-2 on surfaces is easily inactivated at a dose of 3 –10mJ/cm²
  • wavelengths of UV applied

Where is UVGI used?

The COVID pandemic increased interest in the use of UVGI for killing the SARS-CoV-2 virus on surfaces and as aerosols in indoor air. In fact, both the CDC and OSHA recommend UVGI disinfection, especially for purifying indoor air.

  • OSHA considers UVGI disinfection an “engineering control” method –> more effective than safe work practices and PPE such as masks!
  • Centers for Disease Control and Prevention (CDC) recommends using UVGI as a ventilation intervention to reduce the concentration of SARS-CoV-2 virus particles in air.

Surface Disinfection

UVGI devices disinfect surfaces, typically by placing small objects into a UVC light chamber or by scanning a handheld device over the surface. This is especially useful for healthcare worker PPE items such as masks as well as high-touch surfaces such as smart phones, elevator controls, door handles, and restroom sink and toilet handles.

Indoor Air Disinfection

UVGI systems for disinfecting indoor air are typically free-standing, wall-mounted, ceiling-mounted, or ventilation in-duct devices. Except for the in-duct systems, the devices incorporate a fan to draw room air into and through the UVGI lamps to ensure adequate exposure to the UVC light.

UVGI surface and air disinfection systems are ideal for use in all types of commercial buildings:

  • Medical practices, assisted living and nursing care facilities
  • Schools, universities, theaters and concert halls
  • Office buildings and manufacturing production facilities including clean rooms and cold food processing areas
  • Hotels, restaurants, conference centers, fitness gyms
  • Public transportation such as buses, subways, and trains
  • Emergency vehicles and rescue equipment