RALEIGH – The COVID pandemic has resulted in the increasing use of ultraviolet light (UV), the same part of sunlight that tans or burns your skin, to disinfect the air in commercial and government buildings.

Vince DiFrancesco is owner of Homestead Sage. Homestead Sage is a Raleigh-based company that has installed numerous UV-C systems in the Triangle and throughout North Carolina, primarily for large commercial and government clients such as the North Carolina Administration offices in Raleigh.

In an interview with WRAL TechWire, he explains, “UV is the ideal wavelength (253.7 nanometers) for germicidal radiation. It works by disassociating the molecular bond in DNA, disintegrating organic material (253.7 nanometers).”

Vince DiFrancesco, owner of Homestead Sage. Homestead Sage photo

Both corporate and hospital building guidelines recommend disinfecting the air with UV-C.

UV-C systems offer dual benefits to the companies and government agencies that install them. “AC works by transferring heat from airflow over a coil, and because it is a moist environment, there is a tendency to get a buildup of organic contaminants on, and through, the coil’s fin areas. This restricts airflow and heat transfer. Such buildup is eliminated through the use of ultraviolet germicidal energy.”

Also increases efficiency

He has to remain with the companies to clean their drains regularly for about three months as the organic sludge slides off the coil.

“Keeping the coil clean increases airflow and heat transfer, which in turn increases the energy efficiency of the HVAC system, sometimes as much as 20%,” he said. But the disinfected air has another benefit.  “Companies will see less sickness and absenteeism.”

One aspect of installation of UVC is extremely important, he said. Enough UV light must be installed to disinfect the size of the air-managed space. DiFrancesco points out that some commercial air handlers are large enough to walk into. “You could put an office in some of them,” he said.

Installations, however, do not take long. “It’s no different than hanging light fixtures, which is what you’re doing. You could do an entire restaurant in a morning. A single person could do it, but we work in teams of two.”

Could help us go out again

He notes that “UV-C works on staph (MRSA), Ebola, Coronavirus, flu, legionella, molds and fungi. UV-C creates a hostile environment for anything organic,” which is why it’s often used in hospitals.

A Duke surgeon, Deryl Hart, pioneered the use of UV light in hospital operating rooms back in 1936. “This technology has been around for a while,” DeFrancesco said, “But the COVID pandemic increased interest in it,” including his own company, which he founded in 2014.

Duke University, the University of North Carolina at Chapel Hill and North Carolina State University have all done significant research in the use of UV light as a disinfectant across a wide variety of uses on surfaces, for food safety and in various environments.

Numerous North Carolina HVAC companies offer UV-C installations in both commercial and smaller spaces.

While it isn’t currently commonly used in schools, movie theaters, concert halls, bars and other public venues, it could be, DiFrancesco suggests. “This technology is perfect for movie theaters, concert venues and other public spaces.” The UV fixtures could be hung seven feet up on a wall so it wouldn’t hit people but would clean the air.

DiFrancesco said, “If we want to go back out, this could help.”