HVAC Systems and Indoor Air Quality
Guided by current recommendations from the Centers for Disease Control and Prevention (CDC) and the American Society of Heating, Refrigerating and Air-Conditioning Engineers (ASHRAE), the University has expanded efforts on improving ventilation and filtration in all campus buildings in response to a full return to campus on July 19, 2021.
Throughout the pandemic period, Facilities Services has been changing filters and performing preventive maintenance on building HVAC systems, including assessment of building ventilation systems for proper operation.
To improve central air filtration across campus, building box filters have been changed and upgraded to filters with a Minimum Efficiency Reporting Value (MERV) of 13 or higher, as recommended by the CDC and ASHRAE. MERV-13 filters provide increased filtration over standard filters and per ASHRAE are efficient at capturing airborne viruses.
Scheduling of HVAC systems are being reviewed to ensure systems will remain on an hour prior to occupancy and an hour post occupancy each day to allow for air flushing from the space.
Frequently Asked Questions
- What role do building heating, ventilation and air-conditioning systems play in reducing the spread of COVID-19?
- With the exception of older, naturally ventilated buildings, building HVAC systems bring in outside air, which dilutes any potential concentration of infectious aerosols. HVAC systems also provide air filtration, which will capture a portion of any circulating particles, including viruses.
- Does my campus building have adequate fresh/outdoor air ventilation?
- Most buildings on campus are supplied with fresh air through the HVAC system. Fresh air requirements are based on occupant density and space function, and campus buildings are designed to minimum ventilation rates as established by the North Carolina Mechanical Code. Specialty-use spaces, including labs and animal care areas, may have additional ventilation requirements, including ventilation that requires 100% outside air. These campus spaces are designed to established minimum air change per hour (ACH) rates as recommended by the National Institutes of Health.
- Is it possible to increase the outside air ventilation in my area?
- Many campus building systems are designed to increase outside air ventilation during favorable weather conditions, which typically occur during the milder spring and fall seasons. The University is inspecting building ventilation systems for proper operation and will seek ways to increase outside air ventilation when appropriate and as weather conditions allow.
- Should I open building windows if operable?
- Building occupants should not open windows, as this can increase the load on HVAC systems and/or create uncomfortable or unfavorable building conditions.
- Are high containment or HEPA (high-efficiency particulate air) filters used in campus buildings?
- Specialty-use areas on campus, including labs and animal care areas, require high containment or HEPA filters and the HVAC systems in these areas are designed to work with these filter types. Other campus spaces do not require high containment filters and the HVAC systems are not designed for that filter type. There are limited portable HEPA filters in use for classroom spaces that do not have central ventilation systems.
- Should departments install plexiglass barriers in areas where physical distancing cannot be achieved?
- Physical distancing mitigation measures have decreased based on vaccination rates and current transmission rates. Barriers are appropriate in some circumstances where they may provide added benefit. For example, barriers may add droplet protection (“sneeze protection”) in locations with frequent, short duration, close contact with customers and in some health care settings. Barriers are not required in general office areas.
- Are personal portable air filtration units allowed in offices or can departments purchase for individuals?
- While personal portable air filtration units may provide some small benefit, they do little to prevent person-to-person transmission. Additionally, some ionizers can produce ozone and/or utilize UV which can be harmful to eyes and skin. Portable units may also have fire safety risks and contribute to overload of electrical circuits in some locations. Based on these reasons the University is not allowing personal or department acquired portable air filtrations units for COVID-related indoor air quality concerns.
- If I have COVID-19 related questions about my building systems (HVAC, plumbing, electrical, etc.), who should I contact?
- Questions about campus building systems should be directed to Todd Going, director of Building Services, at firstname.lastname@example.org.