White paper examines how to reduce pathogen transmission in ventilation

Experts examined reduced pathogen transmission using a building’s original mechanical design, original installation, design intent, and proper maintenance in a new white paper.

Return Ductwork Requirement for Airborne Pathogens Through the Airstream, discusses two approaches: pressure barriers and airflow distribution. The paper looks at the pros and cons of using the cavity above a finished ceiling as a return air plenum combined with supply air to the air handler as a proper ventilation technique.

Considerations include how ventilation systems affect the health and well-being of building occupants. A ceiling plenum provides some fan-specific energy efficiency and reduced material and labor costs, but it could put occupants and workers at risk and result in unintended energy losses. An open ceiling plenum is difficult to clean and disinfect, while ductwork can be easily cleaned.

A ducted return system allows a testing, adjusting, and balancing professional to adjust room pressures and airflow patterns to accommodate a change in use or mitigate pathogen transmission during a pandemic. Authors of the white paper include members of the American Society of Heating, Refrigerating and Air-Conditioning Engineers (ASHRAE) Technical Committee 5.2 Duct Design.

New York City has two very large buildings dedicated to answering the 911 calls of its five boroughs. With more than 11 million emergency calls annually, it makes perfect sense. The second of these buildings, the Public Safety Answering Center II (PSAC II) is located on a nine-acre parcel of land in the Bronx. It’s an imposing 450,000 square-foot structure—a 240-foot-wide by 240-foot-tall cube. The gleaming aluminum cube risesthe equivalent of 24 stories from behind a grassy berm, projecting the unlikely impression that it might actually be floating. Like most visually striking structures, the building has drawn as much scorn as it has admiration.