A First Look at ASHRAE Standard 241

On June 24, 2023, ASHRAE approved the publication of Standard 241-2023 Control of Infectious Aerosols. The purpose of Standard 241 is "to establish minimum requirements for control of infectious aerosols to reduce risk of disease transmission in the occupiable space of buildings" by defining "the amount of equivalent clean airflow necessary to substantially reduce the risk of disease transmission during infection risk management mode." This column provides a high-level overview of key aspects of the new standard and a discussion of its historical context and its potential impact on design and operation of buildings to achieve improved indoor air quality (IAQ). Future columns will provide more detailed information on the background and use of the standard.