ATLANTA — ASHRAE has published a consensus-based, code-enforceable IAQ standard aimed at reducing the indoor transmission of infectious aerosols.

ASHRAE Standard 241, Control of Infectious Aerosols, establishes minimum requirements for reducing the risk of the transmission of airborne pathogens, such as the SARS-COV-2 virus, which causes COVID-19; the flu virus; and other pathogens in buildings like single- and multi-family homes, offices, schools, and health-care facilities. The standard applies to new and existing buildings and major renovations and provides requirements for many aspects of air-system design, installation, operation, and maintenance.

Important topics addressed in the standard include:

Infection Risk Management Mode (IRMM) — An IRMM applies during identified periods during which the risk of disease transmission is elevated. Authorities having jurisdiction can determine when the enhanced protections of Standard 241 are required. Resilience (the ability to respond to extreme circumstances outside normal conditions) in IAQ control design and operations is discussed.

Requirements for Equivalent Clean Airflow Rate – Sets requirements for an equivalent clean airflow rate target, per occupant, of pathogen-free air flow, which could reduce the risk of infection.

Requirements for Use of Filtration and Air Cleaning Technology — Provides extensive requirements for the use of filtration and air-cleaning equipment (such as HEPA filters, air ionizers, and UV lights) to achieve equivalent clean airflow requirements safely and cost effectively.

Planning and Commissioning — Provides assessment and planning requirements to prepare for the times when there is an event that involves increased disease-causing pathogen transmissions. The standard has a building-readiness plan that documents procedures for assessing existing or new HVAC systems to determine if they are working properly and delivering the proper amount of clean air.

For details, or to purchase Standard 241, visit ashrae.org/241 or contact the ASHRAE Customer Contact Center at 800-527-4723 (in the U.S. and Canada) or 404-636-8400 (from all other countries).