Covid taught us many things, not the least of which being: our buildings aren’t safe. However much we didn’t understand about the SARS-CoV-2 virus in the early days of the pandemic, the ensuing lockdowns and office closures were clear evidence of the fact that we couldn’t trust the environmental conditions of our offices, lobbies, restaurants, elevators (!), and other public and semi-public places to keep us healthy. In fact, we came to imagine them for what they were: boxes of stagnant air, where the sound of a single cough felt like a death knell.

During periods of elevated health risks, such as flu season or, case in point, a global pandemic, operators of commercial and multi-family residential buildings had little recourse for stewardship, save for makeshift Purell stations and social distancing cues. Other alternatives, like performing building flushes, are both costly and energy intensive, and can strain existing HVAC systems. But a better alternative is afoot.

The American Society of Heating, Refrigerating, and Air-Conditioning Engineers (ASHRAE) recently published Standard 241, Control of Infectious Aerosols, which is designed to ensure healthier and more resilient indoor environments. The new standard covers a broad range of building requirements that touch on air system design, installation, maintenance, and operations.

“Even in the early days of the pandemic, the energy impact of emergency measures was a major issue, as was cost,” says William Bahnfleth, Ph.D., a fellow and presidential member with ASHRAE. “The flexibility built into Standard 241 supports compliance in ways that satisfy energy and economic constraints.”

What separates Standard 241 from similar ASHRAE standards—most notably 62.1 and 62.2, which provide consensus ventilation requirements for acceptable indoor air quality (IAQ) in non-residential buildings and residential dwelling units, respectively—is that it explicitly targets the reduction of airborne transmission of infectious aerosols. In other words,…