Much of the population is ready for a return to some normality after months of not working or working from home due to COVID-19, but it does not mean the virus is gone. What can we do to reduce the potential transmission of COVID-19 and future flu-like viruses in our workplaces? As our offices begin to open in Pennsylvania, we need to minimize the risk of transmission to our employees and customers. This is the challenge that businesses and institutions everywhere are facing.
As an HVAC engineer, I view this challenge in the same way I approach other industrial indoor air quality challenges. Try to capture as much of the contaminant at the source, then filter and dilute the rest. The first step is having a generous sick policy to keep potentially infected individuals home. Here are other steps we have been helping clients take to reduce the transmission of viruses in the workplace:
Masks: While inconvenient, masks are an important component of source capture while on heightened alert. Even cloth masks are effective at capturing respiratory droplets which carry the smaller COVID-19 virus. Where masks are not practical and distancing is not an option, consider adding physical barriers such as plexiglass.
Increase Outdoor Air Flow to Your Building: Outdoor air is likely to have much lower concentrations of COVID-19 and other contaminants than indoor air. Ensuring outdoor air intakes are open and investigating methods of increasing outdoor air will allow for more dilution and cleaner air. I recommend also temporarily disabling energy-saving outdoor air control strategies like CO2 demand-controlled ventilation.
UV Lights: I have received a lot of questions about UV lights. Most UV systems are designed for irradiating coils within HVAC units, not for sterilizing fast-moving air. Some systems with higher UV concentrations are available but are primarily intended for the healthcare industry.
Bipolar Ionization: This is the best upcoming technology for air treatment. The positively and negatively charged ions it creates breaks down viruses, bacteria, and gases in the ductwork and throughout the building. Additionally, the charged ions attract smaller particulates together, enhancing the effectiveness of centralized filtration systems. This technology is better than photocatalytic oxidation systems that use small UV lights and a metallic catalyst that often inadvertently create ozone and complaints of a metallic taste.
Fans & Filters: Most of these steps require the HVAC system fans to run constantly during occupied hours. This is an important and easy setting change on most thermostats that is often overlooked. Increasing the MERV rating (efficiency) of filters is an important consideration. Most standard pleated filters are MERV 8, allowing virus particles to pass right through. Replacement filters are available in the same dimensions up to MERV 13 which can capture the virus-carrying droplet nuclei. Paired with bipolar ionization, the filters are even more effective.
By working with a trusted HVAC company like HB McClure, you can keep a clean atmosphere and minimize the risk of spreading COVID-19 and other viruses among your employees and customers.
– Mark Graybill, P.E., HB McClure Engineer