Air Quality Safety Measures
A number of you have expressed legitimate concerns that fall under the general category of air quality, including questions about how we are minimizing the possibilities for airborne transmission of COVID-19. In general, our policy is to create as much air turnover in the buildings as is possible from our systems while filtering and still encouraging aerosol particles to fall as quickly as possible.
We are aware of the Guangzhou restaurant study some of you have mentioned and other tentative evidence of airborne spread, but any airborne transmission appears limited and our air circulation policies are intended to minimize that risk. In the restaurant case, overly strong AC circulation appears the likely culprit. Another point of reference is the household attack rate (the percentage of other household members that become ill) for COVID-19 (about 10 percent) as compared to measles – a highly contagious airborne virus (about 85-90%). Droplets remain the main source of COVID-19 spread and masks the main prevention mechanism.
We have attached the ASHRAE (the American Society of Heating, Refrigerating, and Air-Conditioning Engineers) reopening document for higher education, which is our primary HVAC guidance (although there is much more in the document). For the HVAC equipment on campus that is capable of providing mechanical outside air (OA), we will do our best to increase these systems when and where needed to prevent exceeding a threshold of 800 ppm Co2. This guideline will ensure that we are providing an adequate amount of fresh air into these spaces to ensure appropriate air turnover. On average, we can turn over the air between 8 and 14 times per hour. By comparison, CDC standards for air turnover in hospital airborne infection isolation rooms (AIIRs) are 6 times per hour in older construction and 12 times per hour in new construction. We have personnel visiting and dating random areas in the buildings throughout our campus with a portable monitor to record temperatures, relative humidity, and Co2 ppm levels. This information will be available upon request.
Our team has gone above and beyond to replace every filter on campus and clean most of the indoor coils, and we should all thank them for the enormous amount of work they have done in a short time. The most commonly used filter on campus for buildings with OA mechanicals is a MERV-8, but some buildings have secondary MERV-14 filters. All residence hall filters have been replaced with MERV-8. Short answer is that higher numbers restrict more air flow, and we have used the filters available that still allow adequate air flow as above.
For the buildings that must use operable windows (that do not have mechanical outside air capabilities), the occupants of the room should open or close windows as they feel necessary. (Fully opened to cracked open depending on what’s needed). Temperature and humidity levels can vary throughout the day, and without instruments it can be difficult to determine the current conditions. The big issue we may have is maintaining adequate humidity levels. For example, Herman Hall has two large ERU’s (energy recovery units) that supply fresh air throughout the building. Opening windows in this building on a humid day will increase the dew point disabling the chilled beams and may cause condensation issues. The screens have now been installed on Herman. Please monitor if you have classes or work in the building.
Below is the list of principal buildings, showing if they have OA mechanicals. If you have questions, please do not hesitate to contact Peter Goodale, our HVAC Manager, at x1782 or by email at firstname.lastname@example.org. Peter is more than happy to answer your questions.
Blake Hall: Mechanical OA for most of the building. CO2 controlled system for new edition.
Campus Center: Mechanical OA for entire building.
Campus Police: Mechanical OA for entire building.
Churchill: No mechanical OA in this building. Must use windows.
Commonwealth: Mechanical OA for center areas, hallways, and bathrooms. No mechanical OA for dorm rooms, must use windows.
CSP: Mechanical OA for entire building. CO2 controlled system for RTU-1 only. RTU-1 serves the larger classrooms/auditoriums.
CUB: Mechanical OA except some shops in the basement.
D’Amour: Mechanical OA for entire building.
Deliso: Mechanical OA systems except basement
Emerson: Mechanical OA on univents for heating season, questionable if any still function. Nothing for AC, must use windows.
Evergreen: Mechanical OA for common area. Nothing in dorms, must use windows.
Gateway: No mechanical OA system.
Herman: Mechanical OA for entire building.
AHLC: Mechanical OA for all areas but basement. Basement does have an exhaust fan.
LaRiviere: Mechanical OA for entire building.
Quads: No mechanical OA capabilities. Must use windows.
Rivers: Mechanical OA for center area gym only. Must use windows for all perimeter offices.
Sleith: Mechanical OA for entire building. All units are CO2 controlled.
Southwood: Mechanical OA for hallways/bathrooms only. Must use windows in the dorm rooms.
University Commons: Mechanical OA for entire building. CO2 controlled system for 4th floor only.
Welcome Center: Mechanical OA for entire building.
Windham: Mechanical outside air possible with 6 round duct dampers. Preferably to have these under enthalpy control on the EMS.