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ASHRAE Completes Draft of Pathogen Mitigation Standard

May 16, 2023
The public review draft is posted and comments can be made through May 26.

ATLANTA (May 15, 2023) – ASHRAE announced the completion of the first draft of its standard for maintaining healthy indoor air quality (IAQ). ASHRAE anticipates a June approval and July publishing date.

ASHRAE Standard 241P, Control of Infectious Aerosols provides minimum requirements for HVAC-related measures to reduce the risk of transmission of COVID-19, influenza, and other airborne viruses in homes, offices, schools, hospitals during periods of high risk. The standard offers guidance for creating healthier environments in the buildings where people work, live, and play.

“The entire world was touched by the effects of the pandemic and we learned that an effective approach in protecting ourselves from the spread of pathogens is to improve the indoor air quality and ventilation in the buildings that we occupy,” said 2022-23 ASHRAE President Farooq Mehboob, Fellow Life Member ASHRAE. “Nowhere in the world do we have a standard that universally addresses the concept of mitigating pathogen spread and IAQ and ASHRAE is proud to lead in the development of the guidance.” 

The standard will address long-range transmission of infectious aerosols and provides minimum requirements for:

  • Equivalent outdoor air (combined effect of ventilation, filtration, and air cleaning) for use during Infection Risk Mitigation Mode  
  • Room air distribution to reduce risk  
  • Characterization of filter and air cleaner effectiveness and safety  
  • Commissioning, including development and implementation of a Building Readiness Plan  
  • System operation in Infection Risk Mitigation Mode during periods of high risk  
  • Maintenance tasks and their minimum frequency  
  • Residences and health care facilities. 

“Standard 241P is built on ASHRAE’s longstanding leadership position as a developer of consensus indoor air quality standards and the guidance developed by the ASHRAE Epidemic Task Force in response to the COVID-19 pandemic,” said ASHRAE Presidential Fellow and Standard Project Committee 241P chair William Bahnfleth, Ph.D., P.E. “This experience, combined with the efforts of a truly world-class international project committee, have allowed us to produce this review draft in only 10 weeks. It is a groundbreaking document that we expect to have significant impact. We look forward to the public’s comments as we work to complete the final version of the standard for publication.”

The committee is seeking comments on the normative portions of the standard. The public review draft is posted and comments can be made at through May 26.

For all standards related activities including announcements, public review drafts open for comment, call for members and more, sign up for ASHRAE Standards Actions at