By Craig ColganAs more retail banking centers, stores, schools, restaurants and other public-focused businesses strain to return to longer opening hours, even as pandemic dangers persist, many are confronted by confusing challenges.
None of these are greater of course than protecting customers from a threat that is, among other confounding characteristics, invisible.
The Centers for Disease Control and Prevention continues to point out that the main mode of transmission of the coronavirus is via respiratory droplets, as well as acknowledging the danger of aerosol transmission—smaller droplets that can wander beyond a few feet via “mechanically driven” airflows.
Slidell Independent School District in rural North Texas made news in the summer for its installation of a filtration system that allegedly destroys coronavirus that floats through the air. The device’s developers say it renders the virus inactive using heat and can be moved from room to room. The device resembles a typical home A/C condenser, but taller.
Public-facing businesses are investing in other options, including installed and portable UV lights—an option that is not new but in fact has been shown effective in limited contexts. A Maryland restaurant group spent $500,000 for devices installed into 20 locations. One study showed that the virus required exposure to UV light for 20 seconds to reach high inactivation effectiveness, but the Air Conditioning Contractors of America notes that UV rays are likely effective only on viral particles on surfaces, pointing out there is no research regarding UV beam effectiveness on virus as it travels through the air.
Paul Benda, ABA’s SVP for risk management policy and in-house expert on all things COVID-19, points out that banks must consider cost and other issues before leaping into investing in unproven “coronavirus killer” devices. He strongly recommends the use of portable air cleaning devices such as HEPA filters. “In general, they are an unadulterated good in this environment and will continuously reduce viral loading in a space,” Benda says. “In fact, I’ve purchased a desktop model for my wife to have on her desk at work.”
He adds he has not heard of banks installing any exotic devices claiming instant virus-killing capacity. Benda instead points to the ABA Guide to Restoring Normal Operations, which recommends installation of MERV-13 or 14 filters in HVAC system air returns, which may be possible in some systems without fan upgrades. Higher-level filtration, including HEPA filters, provide significantly more protection, but likely cannot be implemented without significant system upgrades due to the increased pressure drop across the filters.
The CDC also points to the value of increasing the flow of outdoor air into buildings as much as possible, as well as the use of fans.
The ABA guide addresses the UV systems, noting: “The virus has proven to be susceptible to UV light, but these types of systems must be engineered properly to correctly work, including ensuring the fluence levels of the light are high enough to neutralize the virus at the system flow rate and duct size. Strong consideration should be given to only using vendors with expertise in designing and installing these types of systems.”
No one HVAC or UV system change is a panacea. “A virus can be swept up, carried through the duct system, or it may be able to pass through the air filter, past a clean coil and the UV light,” notes Wes Davis, director of technical services for ACCA. “However, source control can prevent it from entering in the first place. Wear a face mask and practice social distancing. This significantly reduces the likelihood of the virus entering a conditioned space. When you and your customers practice good hygiene and housekeeping (especially for high-touch areas), then any viral infections that might present themselves will be rendered inactive.”