Clearing The Air: HVAC Design for Mitigation Airborne Illnesses
With the COVID pandemic seeming to touch just about every aspect of our lives, it is no surprise that we have owners and architects asking us if there is anything that can be done as part of the HVAC design to help minimize the spread of airborne illnesses like COVID. Unfortunately, there is no magic bullet to stop the spread, but there are some approaches to consider. In increasing order of effectiveness, they are:
Increase Outside Air (where allowable). This is one of the easier options to implement, and decreasing the amount of recirculated air can certainly help dilute the contaminants. Be mindful of the fact that more outside air will increase utility bills to condition or treat the air, and the equipment capacity must be reviewed to ensure it can handle the extra work.
Upgrade Filters. Another fairly simple option is upgrading to filters with rating MERV 14 or higher, or even HEPA (>MERV 16), which can be effective at stopping the spread of contaminants in the return air system. Because these types of filters are designed to trap smaller particles, they do have a higher flow restriction, so keep in mind that you may need larger fans to move the air, as well as more frequent filter changes.
Ultraviolet Germicidal Irradiation. The same technology used by hospitals to disinfect surgical suites can also be used to kill contaminants in your ductwork. However, risks of exposure to humans include skin and eye irritation, and some lamps can produce ozone. Consider that these additions require periodic maintenance.
Needlepoint Bipolar Ionization. The technology creates fields with positive and negative ions. These ions are circulated throughout the space by the HVAC system, and attach themselves to particles, pathogens, and VOCs (Volatile Organic Compounds). The particles bond together, making them larger so that they get captured in a filter that might normally let them though. The ions also break down the surface structure of viruses and bacteria, rendering them ineffective in the space and on surfaces.
While there is no perfect answer, there are a variety of steps that can be taken and, depending on your budget and existing systems, a solution can be designed to supplement your COVID-19 response plan. Contact us, and let us help you consider an appropriate solution for you.