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 mechanical engineers specializing in HVAC, we view this challenge in the same way we approach other industrial indoor air quality challenges. Try to capture as much of the contaminant at the source, then filter and dilute the rest. Here are other steps we have been helping clients take to reduce the transmission of viruses in the workplace.
Increase filtration ratings of air filters
- Option 1: Replace filters in existing units with new ones rated up to MERV 13 (standard pleated filters are MERV 8, spun fiberglass filters are only MERV 4 or lower). This is the best filtration available for most conventional filter racks. The added pressure drop should be evaluated on systems with marginal fan performance.
- Option 2: Add HEPA filtration (better than MERV 13) for part of the return air with a dedicated unit and fan. This is the best type of filter available. This adds no additional pressure drop, but it does not filter all of the return air.
Adjust fan settings
- Turn on HVAC fans continuously during occupied hours to bring in outdoor air and to run indoor recirculated air through the filters.
- Dilution and filtration are some of the best things we can do to improve indoor air quality.
- Bipolar Ionization creates positively and negatively charged ions that breakdown bacteria, viruses and other contaminants in the air.
- It produces no ozone
- Unlike UV technology, the ions continue through the ductwork and interact with the contaminants in the space instead of just what is in the unit.
Increase Outdoor Air
- This allows for dilution of contaminants
- Temporarily disable CO2 demand-controlled ventilation or decrease the CO2 PPM setpoints. Right now, increased dilution of potential contaminants is more pressing than energy savings.
- Add Energy Recovery Ventilators to increase the outdoor air without needing to increase air conditioning tonnage.
- Consider adding dehumidification and humidification, as increasing outdoor air can require these changes. Humidification reduces the life of bacteria and viruses while dehumidification reduces mold growth.