Building Operations Updated January 2021
University Facilities is using guidelines issued by the American Society of Heating, Refrigerating, and Air-Conditioning Engineers (ASHRAE), the Association of Physical Plant Administrators (APPA), the National Institute of Building Sciences, CDC, OSHA and other organizations to make decisions providing for a safe indoor working and learning environment for our campus community.
Recommendations for altering HVAC operations during the COVID-19 pandemic that are applicable on our campus include:
- Increase the volume of fresh outdoor air delivered through HVAC systems and keep HVAC systems running longer hours. Increasing the percentage of fresh air delivered to spaces helps reduce the load of airborne infectious particles. Campus HVAC systems have been designed in compliance with ASHRAE ventilation standards, which require relatively high ventilation rates and thus have the capacity to deliver more fresh air than generally required. Although Facilities has utilized new controls strategies to reduce equipment run-time and ventilation rates and gain energy efficiency for many years, systems will be adjusted back to higher ventilation rates and longer run-times.
- High-efficiency air filtration in HVAC systems. Air filters in central air-handling equipment have been proven effective at removing airborne viral loads. Recirculation of air through filters further reduces airborne loads. Facilities uses high efficiency air filtration where feasible, and uses standard filtration where high-efficiency filters might reduce ventilation flowrates.
- Ultraviolet Germicidal Irradiation (UVGI) of recirculated air damages the structure of airborne infectious particles, rendering them inactive. UVGI is a proven technology, and although testing on COVID-19 has not been completed to date, it is effective against similar strains of virus. Facilities has installed and maintained UVGI air-treatment systems in the central air handling systems on campus since 2014. Although the UVGI systems installed are not intended to sterilize ventilation air, they may provide an extra layer of protection.
- Maintain temperature and humidity as applicable to the infectious aerosol of concern. Humidity levels between 40% and 60% have been shown to reduce the transmission of some airborne infectious organisms. Most central HVAC systems in campus buildings include provisions to control humidity between 40% and 60% relative humidity.
- Select control options, including standalone filters and air cleaners that provide desired exposure reduction while minimizing associated energy penalties. Personal HEPA filters have been shown to be effective in reducing airborne infectious particle. Facilities is providing standalone air cleaners in areas where they will be most beneficial, such as break areas and rooms with low mechanical ventilation rates. While these air cleaners provide an additional layer of protection, they do not reduce the need for distancing and wearing a mask.
In addition to these measures, Facilities performs an ongoing program to clean internal components of central air handlers and replace all air filters.
In academic buildings, windows should not be opened to increase ventilation rates in response to COVID-19. These buildings are provided with a controlled quantity of fresh, filtered ventilated air which will be increased in response to COVID-19. Per ASHRAE recommendations: "Ventilation and filtration provided by heating, ventilating and air-conditioning systems can reduce the airborne concentration of SARS-CoV-2 and thus the risk of transmission through the air." Introduction of uncontrolled outdoor air can, in some cases, worsen occupant health due to allergens present in raw outdoor air.