Most museums showcase art, artifacts, or technology — not the HVAC system. But that is exactly what the Carnegie museums in Pittsburgh, Pennsylvania, are doing with a new exhibit that uses a ceiling HVAC vent to demonstrate how HEPA filters keep indoor air clean.

“HVAC: It’s Like a Mask — For Our Building!” reads a giant blue arrow in the middle of the floor at Carnegie Science Center, pointing upward to an overhead vent. When people look up, they see three more big blue arrows suspended from the ceiling.

“Are You Hep to HEPA?” one reads. “Who the heck is MERV?” says another. The third says “On the case!” and continues, “Environmental engineers are studying the materials to filter out COVID-19.

A Different Form of Art

Art and artifacts require a stable environment, so museums have always taken pains to carefully monitor temperature and humidity.

Melissa Bilec, associate professor of civil and environmental engineering at the University of Pittsburgh Swanson School of Engineering, said the exhibit was a collaboration between the Mascaro Center for Sustainable Innovation, the Carnegie Science Center, and the contractors and engineers that work for the center. The goal, she said, was to showcase the science that goes into building design.

“Engineers do all this great work, and we cover it all up and we hide it, so nobody sees the ductwork or the filters,” she said. “Sometimes I think that what we do is like artwork — but it's always hidden and covered away. I really like that intersection between the two.”

The exhibit points out the relationship between HVAC design, indoor air quality, and museum collections.

“The same dry air that keeps our mummies from getting moldy can damage the delicate paint on one of our artworks,” the exhibit explains. “But in other areas, high humidity, for even just a couple of days, can cause mold to grow, as well as make a comfy habitat for insect pests.”

In addition, particulates like soot, dust, and chemicals in the air can cause damage to collections.

“Have you ever seen a bronze sculpture with light green streaks on it?” the sign asks. “This is caused by acidic air pollution – the chemicals in the air, combined with the humidity and temperature, react with the metal surface causing the metal to corrode and eventually deteriorate.”

HVAC’S Time to Shine

Since the coronavirus is airborne, the quality of the air circulating in indoor spaces like museums has become even more important. The right air filter significantly reduces the amount of pollution entering the building, making indoor air safer for the collections — and for the people who visit.

Carnegie Science Center employs HEPA filters to help keep the air clean, and the internal spaces have a turn rate of two to three times per hour. Bilec’s display shows how filters that are at least MERV 13 or a HEPA filter can help by trapping particles carrying the virus.

Several “slices” of HVAC filters are mounted on the display, with text explaining the functions of each type. It also illustrates the difference between aerosolized particles and droplets, using the analogy of a floating feather versus a golf ball, and explains how both masks and proper HVAC filtration can provide protection against the virus.

“With so much misinformation about COVID-19, I hope our exhibit will teach people about the way our buildings can do some of that important work for us,” said Bilec.

Dennis Bateman, director of exhibits at Carnegie Science Center, said he saw the pandemic as an opportunity to advocate for science literacy in a real-life setting.

"We didn't want to just dwell on the pandemic for our visitors coming to enjoy themselves as an escape from the restrictions in our lives now, but we did want to reassure them about our precautions while they are here, to connect research to real-world examples,” he said.

The display will be featured at Carnegie Science Center as well as other Carnegie museums, including The Andy Warhol Museum.