Modern Building Services

24 MODERN BUILDING SERVICES NOVEMBER 2021 FEATURE INDOOR AIR QUALITY Workers Still Fear a Return to Buildings How HVAC Can Help Ease Trepidation . Identifying Concern According to Korn Ferry (a global HR consulting firm) 50% of worldwide workers are afraid to return to their offices despite social distancing practices that have been implemented, such as limiting occupancy, employee temperature scanning, face masks, special workspace accommodations, additional cleaning measures, etc. Within cities, more people are starting or continuing to work from home which has resulted in office vacancies skyrocketing and rents plummeting. Information from Colliers International (a leading global commercial real estate service and investment management firm) reports that vacancies soared by 10.2% in the first quarter of 2020 and have continued to rise. The commercial real estatemarket is experiencing negative impact to their financial bottom line as never seen inmore recent times. What can be done to ease trepidation and help reengage our workforce population back into an eager economy awaiting their return to buildings and structures of all types? One important piece to this puzzle may be something recently dubbed “HVAC Social Distancing”, but what does that really mean? In Figure-1 you will notice the slight difference between the left-and right-hand pictures. By implementing specific Heating, Ventilating, and Air-Conditioning (HVAC) systemmeasures such as effective ventilation and filtration, along with the addition of Advanced Air Cleaning Technologies, professionals in the facility management and HVAC fields are striving to drive a wedge between building occupants and the very small “droplet nuclei” aerosols (in red circle) transporting airborne virus, that when inhaled may result in the transmission of COVID-19 along with other diseases. Recent Guidance Unfortunately, little is yet is really known with regard to the novel SARS-CoV-2 virus which causes the disease COVID-19. Preliminary research indicates this virus (like many others) can be transported within the air as fine or ultra- fine submicron particles, further classified as droplet nuclei. These are the result of respiratory fluids which are aerosolized when expelled to the indoor environment by an infected individual who may be coughing, sneezing, talking, or breathing. These aerosol droplets include mucosal and saliva fluids containing an assortment of liquids, salts, viruses, bacteria, volatile compounds, etc. A scientific study published in the American Journal of Infection Control titled Particle Control Reduces Fine and Ultrafine Particles Greater than HEPA Filtration in Live Operating Rooms and Kills Biological Warfare Surrogate, has concluded that many very small particles and pathogens may be of insufficient mass to be controlled by bulk airflow and can remain suspended in the indoor air for days or even weeks. It’s reported that significant fractions of the fine and ultra-fine particles in the air may not be effectively transported to or removed by conventional air filters, which of course can only be effective at removing those particles and pathogens that reach them, not those that remain suspended in the space. InNovember of 2020 the American Society of Heating, Refrigerating and Air-Conditioning Engineers (ASHRAE) stated in a journal Industry News article titled ETF Chair: LimitedVirus Knowledge is Key Challenge, that research has not provided evidence of the transmission of (SARS-CoV-2) virus through HVAC systems, althoughwithin a space air motion caused by HVAC systemcomponents as well as fans can be a factor. On March 23, 2021, Centres for Disease Control Preventions (CDC) updated their COVID-19Ventilation FAQ’s titled: Can COVID-19 beTransmitted Through HVACVentilation Systems? They stated that the risk of spreading SARS-CoV-2 through ventilation systems is not currently clear, and that while airflows within a particular spacemay help spread disease among people in that space, there is no definitive evidence to date that viable virus has been transmitted through an HVAC system to result in disease transmission to people in other spaces served by the same system. In a January 2021 peer- reviewed ASHRAE Journal article titled PreparingHVAC Systems Before Reoccupying a Building, authors stated that the growing science around far-field aerosol transmission may essentially negate the need for in-duct or air systemcontrol technologies such as UV lights. Actionable Solutions Based on current guidance it appears evident that we may want to consider addressing occupant transmission of SARS-CoV-2 in the space itself, where it originates and may remain. While traditional ventilation and filtration are the INDOOR AIR QUALITY