Increased air circulation, filtration part of fall semester prep

· 4 min read

Increased air circulation, filtration part of fall semester prep

HVAC
Craig Chandler | University Communication
Lloyd Blessing, zone preventive maintenance associate, unpacks new air filters being installed in Westbrook Music Building to improve the air quality in campus buildings.

University of Nebraska–Lincoln preparations for a return to in-person, on-campus instruction this fall are now focused on bolstering indoor air quality.

Led by the university’s facilities team, the work includes increasing fresh air circulation and improving filtration in all campus buildings. The adjustments are meant to reduce potential impacts if the COVID-19 virus becomes aerosolized, or lingers in the air for extended periods of time.

“Much about how this virus spreads is still being discovered; however, with some initial studies indicating that airborne transmission is a possibility, it’s our responsibility to be proactive and do what we can to keep students, faculty and staff healthy,” said Lalit Agarwal, director of maintenance and utility services.

Agarwal and his team are following new COVID-19 guidance issued by the American Society of Heating, Refrigerating and Air-Conditioning Engineers, in accordance with the Centers for Disease Control and Prevention, to inform the HVAC improvements.

Under the new guidelines, fresh air that is pulled in from outdoors will be nearly doubled from pre-pandemic levels.

“We are taking a liberal approach and increasing the amount of fresh air intake by two times the minimum recommended by ASHRAE,” Agarwal said. “Our team has already implemented that change using the control system that all campus buildings are connected to. In a sense, it was actually a relatively easy change to make.”

Dave Tyler, control systems tech, uses a hot wire anemometer to measure air coming from a vent in a practice room in Westbrook Music Building.

Facilities workers are also upgrading filters to capture smaller particles in the air.

“All the air handlers in campus buildings have filters,” Agarwal said. “You may have changed the filter in your own furnace at home sometime — just imagine a much bigger set of filters. Sometimes they’re as big as a living room.

“We’re able to measure the level of particles being filtered using a standard system called MERV, or Minimum Efficiency Reporting Values. MERV 8 is the lowest rating of filters used at UNL, and MERV 15 is the highest. ASHRAE is now recommending that we install MERV 13 filters, which stop particles that are 0.3 to 1 micron, in all buildings.”

While the new filters can’t completely eliminate the presence of the virus in the air, they are effective at blocking larger particles that may carry it.

“The virus itself is still smaller than what we can filter; however, if it is sitting on a dust particle or vapor droplet, this will make it harder for it to pass through the filtration system,” Agarwal said. “It’s not foolproof, but it reduces the risk significantly.”

The team is aiming to be finished with the campuswide HVAC adjustments on Aug. 10. In the meantime, Agarwal recommends that students, faculty and staff focus on small, day-to-day measures that are proven to prevent the spread of COVID-19 — hand washing, mask wearing and social distancing.

“Somebody coughing or sneezing on you, or you touching a surface that somebody who was infected touched, are still the most common ways to catch the virus. They’re also situations we can prevent through proper precautions this fall,” Agarwal said. “Those coming to campus should know that we’re looking at every possibility to keep them safe.”

The HVAC system upgrades are a new measure in a layered approach the university is taking to reduce potential impacts of the COVID-19 virus. Other measures include requiring the use of facial coverings; mapping classrooms to allow for social distancing,; creating large-scale hand sanitizer stations; focusing cleaning in key areas; preparing flexible instruction plans; extending acute care (including access to COVID-19 testing) to students, faculty and staff through the University Health Center; and working with TestNebraska to create a dedicated COVID-19 testing facility on campus.

Learn more about the university preparations for the fall semester.

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