Operations: FAQs

When we look at the heating ventilation and air conditioning systems on campus and the air that's being moved throughout those systems, we want to understand the two main transmission paths for COVID-19. The droplet-based transmission stays in the immediate area because it's impacted by gravity. The droplets are large enough that they're pulled out of the air within that three to six-foot range. There's also the aerosolized transmission path. This is a much smaller particle that is not impacted by gravity and can ride on air currents, traveling great distances including into the exhaust system for the heating and cooling ducts.

Since March we have taken specific actions throughout the campus pointing to the heating ventilation and air conditioning side such as maximizing the dilution ventilation and maximizing the amount of outside air. This is the best path forward for droplet-based transmission and for aerosol-based transmission. This dilutes the concentration of particulate in the air, and minimizes the possibility of spreading through recirculation.

For more information on how UCI is handling indoor air quality as people return to campus, watch Anteater Insider Live: Episode 2 | The Health of Indoor Air.

We're working with many partners throughout the industry to understand how to implement the best mitigation strategies for COVID-19. We're currently working with both CDC and the World Health Organization's guidance and implementing the American Society for Heating Refrigeration and Air Conditioning Engineers (ASHRAE) recommendations. We also work with some of our campus partners like Three Flow Technologies, Taylor Engineering and the UC Office of the President.

For more information on how UCI is handling indoor air quality as people return to campus, watch Anteater Insider Live: Episode 2 | The Health of Indoor Air.

First and foremost, facilities management has had continuous operation of heating ventilation and air conditioning systems throughout campus. Since COVID began, we did not shut down buildings, even though there was a curtailment of classes and work on campus. That also means that we didn't curtail or shut down our maintenance program. We continued all maintenance on campus throughout the heating ventilation and air conditioning (HVAC) systems, which puts us in a much better position coming back to campus as those systems had no stagnation and were maintained throughout the entire time.

HVAC filters are rated in MERV ratings from 1 to 20, and 17 through 20 are what are referred to as HEPA filters. HEPA filters have the highest efficiency and remove the smallest particles from the air. Unfortunately, those filters are not compatible with the air handling units and air conditioning systems that we have on campus.

Industry standard for places like grocery stores, restaurants, and other common buildings that you might travel to is a MERV-8 rated filter. A home furnace might have a MERV-8 rated filter. These filters are utilized in some campus trailer and temporary buildings. UCI buildings with small air handlers were MERV-10 and are being upgraded to a MERV-13 rated filter. The MERV-13 level of filtration is the ASHRAE recommended filter in response to COVID-19. UCI buildings with larger handlers such as Aldrich Hall, Biological Sciences 3 and Engineering Hall all have MERV 15 filters. MERV 15 filters are used exclusively throughout the campus in our large air handlers and are several steps above the ASHRAE recommendation.

For more information on how UCI is handling indoor air quality as people return to campus, watch Anteater Insider Live: Episode 2 | The Health of Indoor Air.

With respect to the HVAC systems campus has reduced occupancy, which increases dilution ventilation, and we have increased the percentage of outside air flow, and are flushing buildings with fresh air before and after occupancy. These steps mitigate the risk of spreading COVID-19. Filtration also mitigates risk however the transmission of the virus can still occur.

Labs zones utilize 100% outside air. The air enters the air handler where it is filtered, heated, or cooled, and then supplied to the lab zones. All of the air is then exhausted with no re-recirculation or re-entrainment. Labs have high volumes of dilution ventilation and utilize high MERV filtration ratings.

For the offices and classrooms, we have what we call a return air system. This is basically supply air from the outside mixed with some portion of return air. All of the air is cooled/heated and filtered. Currently we modulated the amount of outside air to maximize outside air and limit the return air that goes back into the building. We also have the high to medium MERV filtration, rated filters.

Trailers, and temporary buildings that we have on campus have limited outside air. They have high levels of recirculation, and most of the exhaust is through exfiltration of the building. They also have the lowest MERV rated filters on campus. Which are still at industry standard or a MERV-8 rated filter.

Any time you can increase the dilution ventilation which lowers the concentration of particulate or virus particles in the space will lower the potential dose you could receive. You should never open a lab window as those zones are specifically designed to capture any effluent in the lab zone and exhaust it safely.

If you are able to find and “open air” meeting space, you are welcome to convene your meeting there. However, keep in mind that “Open air” does not mean contaminant-free air. Anyone in the path of the air currents (wind) will be exposed to anyone upstream. There will be more particles in the air outside than there are particles inside a building with filtration.

Here, too we rely on the CDC guidance. These smallest spaces, such as bathrooms and elevator are ventilated 24/7. These spaces operate using fixed exhaust fans, which run 24/7, so those spaces are constantly being exhausted.

However, they still present a challenge in that it is difficult to physically distance and people must adhere to the face covering directive in these spaces to help prevent the spread.

There is no reason to bring in personal fans, the air conditioning systems are still cooling as designed. Fans may help spread the virus, or push the virus spread further depending on how they are used.

The HVAC systems are continuously monitored utilizing building management systems and a network of sensors.

As part of Facilities Management’s comprehensive preventative maintenance program, our skilled technicians inspect, clean and maintain building air-handling systems biannually. Preventive maintenance includes:

• Vacuuming and cleaning air intakes and catch basins and air-handling rooms
• Washing air handler fins and coils
• Checking and replacing all pre-filters and filters at least once a year, more often on smaller buildings
• Cleaning and treating the water in all closed-loop systems

For more information on how UCI is handling indoor air quality as people return to campus, watch Anteater Insider Live: Episode 2 | The Health of Indoor Air.

At this time, we're implementing the best strategies possible to mitigate COVID-19 throughout the campus. We've reviewed personalized ventilation systems and UV lighting systems, including their effectiveness and whether or not they can be implemented on campus.

The feasibility of adding air purification sterilizers to existing air conditioning systems, especially ultraviolet light is being scrutinized by the industry for effectiveness. Ultraviolet light has shown to kill COVID-19. However, in a heating ventilation and air conditioning system the air is moving so quickly, there is not enough time for the UV light to be effective on the COVID-19 virus, as it moves through the air.

UCI trailiers use filters with a MERV 8 rating that are effective in filtering particles such as mold spores, cooking dusts, hair spary and furniture polish. MERV 8 is insudtry standard

UCI buildings with small AHU's use filters with a MERV 10 rating that are effective in filtering particles such as lead dust, flour, auto fumes and welding fumes. Faciiltes Management recommends these filters be upgraded to acheive a MERV 13 rating and the ability to filter particles such as bacteria, smoke and sneezes.

UCI buildings with large AHU's use filters with a MERV 15 rating that can filter particles similar to those as MERV 13 filters, but with greater efficacy.

Learn more about MERV ratings on the EPA website.