The way we work and design is changing on a daily basis. We've been exploring how we will change our design choices to help reduce infection risks in buildings regardless of the facility type. This can be accomplished in several ways with minor improvements to building systems including HVAC filtering and lighting using a photobiology application that has been in use since the 1950’s. Known as UVGI or GUV, germicidal ultraviolet light is a wavelength available in many commonly used lighting products including emerging technologies in LED and krypton-chlorine excimer lamps.
How does UVG work?
A recent Illuminating Engineering Society (IES) committee report explained using “emitting low- and medium-pressure mercury lamps, as well as pulsed xenon arc lamps. Studies have shown that these technologies—continuously emitting or pulsed—are comparably effective for disinfection."
Essentially, when applied in a given location, wavelengths in the photobiological ultraviolet spectral band known as the “UV-C,” from 200 to 280 nanometers (nm), have been effective for disinfection. UV-C can effectively inactivate the SARS-CoV-2 virus, responsible for COVID-19. You can read in more detail about the technical aspects of this in the Illuminating Engineering Society (IES) report.
While many applications of UVGI have been in healthcare, laboratory, and military environments, germicidal use of UV radiation can be applied to commercial use at a relatively low cost. There are some precautionary measures that should be applied when using this technology in lighting and HVAC system design but it is accepted by NIOSH, the CDC and WHO as safe for use when installed and maintained properly.
Possible applications in Commercial Building Design include:
Applying UVGI to the upper air of spaces when people are present. This is likely the most common way we will be able to use UVGI in commercial spaces as it involves less risk of exposure to UVGI safety concerns.
Downward UVGI lighting in spaces where people are not present or access can be controlled during off hours. This exposure needs to be carefully monitored and controlled for access and duration of exposure.
UVGI can also be applied in a whole building approach in recirculation of air or in-duct UV lamps. This is commonly used in healthcare spaces and is recommended as a secondary approach to treating recirculated air. Unfortunately, this method of treating air does relatively little to prevent person-to-person transmission in a room where both an infectious source and other susceptible persons share the same air. This is also often restricted by space available for the systems and the maintenance and operation required. We will discuss this inmate depth in our HVAC design considerations blog.
While there is little evidence in real world applications of germicidal UV effectiveness, many studies have been done over time that demonstrate it can be highly effective in reducing airborne pathogens. It has been determined to be safe when used and maintained properly and could be a major consideration for schools, doctors offices, retail, and large office buildings to help reduce risk of viruses like COVID-19.
For more information on UVGI contact Tec Inc. or visit IES for information on current standards.
Contributors
Brandon Sargent, PE, LEED AP BD+C Project Manager | Associate
Brandon leads our Pittsburgh office with a friendly flair to his electrical engineering and lighting design expertise. He's often referred to as our office Boy Scout since he earned the Eagle Rank as a young man and is always prepared for any client question or project concern. He's also a leading lighting design expert in our firm and works in collaboration with award winning lighting designers to provide electrical engineering coordination with drawings and proper power requirements.