This article was composed from a conversation with U.S. Engineering Service team members in our Flint Hills Region, with offices in Wichita and Manhattan, Kansas. Contributors include Richard Jones, General Manager, Travis Matteson, Field Operations Manager, Aran Ryan, Account Manager, and Luke Sloan, Account Manager.
When the pandemic broke worldwide last spring, our Service and Construction teams, deemed essential, continued to build and maintain mechanical systems. We delivered on projects in hospitals, field hospitals and alternative care facilities, which rely on our ability to ensure that clean air flows through rooms meant for testing, surgeries and other crucial medical procedures.
These days, as people are returning to office buildings, schools and public spaces, the discussion about air quality has expanded. On our end of the business, we’ve noticed a higher volume of inquiries on preventative measures building owners and operators can take against potential pathogens flowing through the air.
To date there is no scientifically proven silver bullet to kill 100% of the airborne particles of the virus that causes COVID-19, but there are best practices we can follow to improve indoor air quality and—along with wearing face coverings, social distancing and washing hands—to bolster our defenses against the virus and other potential health hazards. Organizations, such as the Centers for Disease Control (CDC), the American Society of Heating, Refrigerating and Air-Conditioning Engineers (ASHRAE), the Occupational Safety and Health Administration (OSHA) and the Mechanical Service Contractors Association (MSCA), offer guidelines and suggestions for keeping the quality of indoor air as safe as possible.
We understand that these days budgets are tight, and information seems to be changing at a rapid pace. Here are some precautionary measures building owners and operators should consider when looking to improve their airflow systems, along with some notes about cost effectiveness.
Increase your system’s outdoor ventilation rate. That is, increase the rate at which outdoor air replaces indoor air in the building. Adding to those exchanges brings in fresh air and expels potentially contaminated indoor air.
However, the cost of modifying existing equipment can be a roadblock to this process. Often systems aren’t sized to handle an increase in outdoor ventilation—especially during the summertime, you may run into an issue with humidity. If you’re building a system from scratch, engineers can design for the possibility of increased airflow, but retrofitting older systems may require new, expensive equipment. Luckily there are several other methods you can employ to improve indoor air quality.
Upgrade your air filters. Efficiency in removing particles from the air is measured in Minimum Efficiency Reporting Value (MERV). MERV filter ratings range from 1 to 16 in, with 16 being the most effective in capturing particles from the air. ASHRAE recommends using filters with a MERV ≥ 13. However, when upgrading your filters to a higher MERV, be sure that your HVAC system can handle the new MERV level filter without a negative impact to pressure differentials or air flow rates.
Need a more effective air filter than a MERV-16? Use a High Efficiency Particulate Air (HEPA) filter. Again, check to make sure your system can handle that degree of filtration without a drop in pressure or lower rate of airflow.
Use portable air cleaners in addition to your building’s HVAC system. Portable filters can clean the air in a space and change a room’s directional air flow, improving ventilation. Types of portable systems vary widely, but those using serious filters, like HEPA filters, can act as another layer of defense against pathogens in the air. The EPA notes that portable systems are not a substitute for broader ventilation and filtration systems, but they can be useful when used in tandem.
Run your system 24/7. The longer your HVAC system runs, the more fresh air exchanges occur, and the higher the degree of air filtration. Additionally, consider adding remote access to your building management system, especially if occupancy in your building varies. With remote access, you can increase the time your system is operating when more people are in and out of your building, and you can decrease the time when the building has a lower or less-frequent occupancy rate.
Ultraviolet (UV) light. In addition to increasing air exchanges and upgrading your filtration, you can deploy agents into the air or onto surface that kill potentially harmful particles. UV light systems can be used to “clean” air and surfaces alike, as they are known to inactivate viruses, bacteria and fungal organisms, rendering them unable to reproduce and spread.
Whether located inside ducts, deployed by portable units, or focused on coils, drain pans or other wet surfaces, UV light can work to kill particles. However, cost may be an issue with UV light as maintenance costs—installation and replacing bulbs, for example—can add up over time.
Clean indoor coils regularly with biocides. As with UV light systems, at the time this article was published, there are no completed, peer-reviewed studies that prove biocides kill the virus that causes COVID-19. However, biocides have been used effectively on microorganisms, such as viruses, bacteria and fungi.
Bipolar ionization uses a technology in which charged atoms are released into the air to deactivate microorganisms like viruses. It is perhaps the best bang for the buck, generally more cost effective in the long run than UV light or biocide disinfectants. This proactive method can send charged atoms throughout a building, originating at the ducts, to destroy potentially harmful particles.
The last, and arguably the most important, insurance policy we suggest for improved air quality is maintaining a regular service schedule. As you consider extra precautions for your system, don’t forget to continue to make sure your system is operating like it’s supposed to. Clean or change filters regularly. Check your dampers to make sure they’re working properly. Do all the things you usually do for your system to make sure it’s balanced and working properly.
COVID-19 is still relatively new, and as more research is completed, more exact methods to clean the air specifically for that virus will certainly arise. In the meantime, these suggestions can guide you as you work to improve your building’s indoor air quality.