By Scott Sklar
As the COVID-19 pandemic continues to impact the United States and the world, executives continue to make difficult choices about facility reopening, employee safety, and operational support. Amidst a realization that we may never completely return to pre-pandemic conditions, facility managers are identifying ways to make the “built environment” as safe as possible while still being mindful of energy usage. To that end, there is an increasingly broad universe of tools available, including chemical based surface sanitation, air-purifiers and filters, HVAC system improvements, and ultra-violet (UV) lighting.
Facility executives are increasingly taking a more sophisticated and comprehensive approach to reducing the risk of infectious disease inside their buildings by utilizing a layered approach to mitigation and disinfection. Public attention has been focused on masks, social distancing, and vaccines. Still, continued reliance on these tools will not completely prevent the spread of disease because they don’t eliminate or remove pathogens from our occupied spaces.
Like many other infectious diseases, the primary means of COVID transmission appears to be airborne, and consequently, the single, most important factor in the control of airborne threats is clean air. The Centers for Disease Control (CDC) recommends that the best means of controlling infectious disease is to provide clean, pathogen-free air in an enclosed, occupied environment. To that end, ventilation, HEPA filters, and UV light are the only evidence-based methods recommended by the CDC for airborne infection control.
Let’s Look At UV Light In Infection Control Efforts
Of those options listed above — ventilation, HEPA filters, and UV light, one of the least utilized COVID mitigation strategies is UV light, even while it has been used successfully to treat the majority of the country’s hospital operating rooms for decades. Upper Room UV and Whole Room Far UV are readily available, affordable, and can safely eliminate hazards by sanitizing the air and surfaces in our indoor spaces. Far UV, in particular, utilizing narrower wavelengths of UV light (around 222nm), has proven to be a safe (will not harm skin or eyes), effective, and easy to implement.
While most buildings outside of hospitals have Air Changes per Hour (ACH) between zero and three, the CDC recommends a minimum of six ACH to ensure that there is sufficient clean air circulating to prevent disease spread. Conventionally, most people consider this to be largely a HVAC issue and focus their efforts and resources on upgrading and replacing HVAC systems to provide the required ACH. While better and more efficient HVAC is beneficial, this comes with the cost of replacement systems, installation, maintenance, and energy use.
Interestingly, too much air flow may also have an unintended result. A recent modeling study suggests that vigorous ventilation can cause a spike in viral concentrations in adjacent spaces. Published in the journal Building and Environment, a team of researchers at the U.S. Department of Energy’s Pacific Northwest National Laboratory, which included building and HVAC experts as well as experts in aerosol particles and viral materials, studied the effects of different MERV filters. The team found that a rapid rate of air exchange (twelve ACH) in a source room reduced transmission risk by 75% but also caused a spike in viral particle levels in connected rooms. After only a few minutes, this increase in viral load in adjoining spaces increased the risk of infection to more than 10 times what it was at lower air-exchange rates.
HVAC use accounts for a significant portion of facility energy use, sometimes a third or more in many buildings. In the western and southern U.S. where air conditioning is used eight months or more out of the year, and in northern climates where heating systems are used five or more months of the year, studies indicate that increasing HVAC air flow adds 5-12% to total energy costs (depending on system efficiency). Air optimizers can compensate for some of this loss, but the cost for air filters, labor, and required maintenance will often negate these savings. Other than reduced use, replacement, or upgrade, facility managers’ options to reduce HVAC-related energy costs include: reducing run times, adjusting equipment sequencing, reducing static air pressure settings and other system modifications. However, these may not generate significant savings and can come at the expense of occupant health. Given the current problem of returning our workforce to the built environment, managers will continue to struggle with the increased costs of HVAC usage, especially when faced with the need to increase ACH as a COVID mitigation tool.
Advances in Far UV lighting can provide a solution to the high cost of increased HVAC use, physical cleaning costs and human error, and the unintended consequences of increased air flow. Far UV light in the 222nm range is already a preferred disinfection solution for many Department of Defense organizations, is increasingly protecting schools, transportation, and healthcare facilities, is eye and skin safe, disinfects both air and surfaces in an enclosed space, and uses significantly less energy than increased HVAC use. Far UV solutions are also low maintenance; once installed, the bulbs last for many years, and require virtually no upkeep. Far UV can continuously and autonomously eliminate over 90% of pathogens in the air and exposed surfaces of an enclosed space even when occupied with a COVID-infected person (providing an equivalent of 35 ACH). Far UV lighting provides facility executives, managers, and staff with a critical, easy to rapidly deploy, continuous, autonomous and cost-effective tool in the fight against COVID, as well as other infectious disease threats like cold and flu. Utilization of this technology, especially as part of a layered approach, can provide comprehensive protection for employees and building occupants, enabling facility reopening, increased building utilization and tenant demand, and facilitating normal business operations.
Sklar is an advisor to Far UV Technologies, a creator of autonomous persistent disinfection devices. He is an Adjunct Professor & Sustainable Energy Director of the Environment & Energy Management Institute (EEMI) at The George Washington University. Far UV Technologies has designed, developed, tested, and demonstrated Far UV solutions for several years, including under contract with NASA to prevent foodborne illness in space flight, with awards from the US Army for medical applications and the US Air Force for SARS-CoV-2 remediation throughout their facilities, vehicles and aircraft.
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