top of page

Session 1 - New Hampshire Room

October 30, 2023 @ 8:30-9:30 am
Click here to download presentation PDF


Screenshot 2023-08-16 115710.jpg

ASHRAE’s New Standard 241 – Airborne Infection Protection for Buildings

William P. Bahnfleth, Professor of Architectural Engineering, Pennsylvania State University,
State College, PA

About this program:

ASHRAE Standard 241-2023 – Control of Infectious Aerosols is ASHRAE’s newest standard. It establishes minimum requirements for systems in new, existing, and renovated buildings to significantly reduce the likelihood of airborne disease transmission indoors when risk of infection is deemed to be high. It was developed in response to encouragement from the White House to create a national pathogen mitigation standard. Standard 241 is innovative in number of areas, including the use of equivalent clean airflow as the target performance metric, the introduction of resilience concepts into IAQ standards, and the establishment of air cleaner performance and safety tests. This presentation will give attendees a thorough introduction to Standard 241, including explanation of key concepts including equivalent clean air, infection risk management mode, and building readiness plans and how Standard 241 relates to existing IAQ standards such as ASHRAE 62.1 and building codes. Supporting tools and guidance such as the equivalent clean air calculator and procedures for determining clean air delivery rates for particle removal systems by field testing will be described. Attendees will be better prepared to read the new standard with comprehension and to apply it effectively.

Learning Goals:

At the end of the session, attendees should be able to:

  • Understand the purpose and scope of ASHRAE Standard 241

  • Define “Infection Risk Mitigation Mode”

  • Define “Equivalent Clean Air” and calculate the equivalent clean air requirement for a simple space

  • Explain the purpose of a Building Readiness Plan and how it is developed

  • Summarize the testing requirements for filters and air cleaners in Standard 241

About the Presenter:

William Bahnfleth is a professor of architectural engineering at the Pennsylvania State University.  In previous positions, he was a facilities researcher for the US Army Corps of Engineers and a consulting engineer. He holds a PhD in Mechanical Engineering  from the University of Illinois at Urbana-Champaign and is a Registered Professional Engineer. His teaching and research interests include HVAC systems and indoor air quality. He is the author of nearly 200 scientific and technical publications. A particular interest is energy efficient control of bioaerosols using alternatives to dilution with outdoor air  Dr. Bahnfleth is a Fellow of ASHRAE, ASME, and ISIAQ. He is a past President of ASHRAE and Vice President of the Indoor Environmental Quality Global Alliance. He  chaired the ASHRAE Epidemic Task Force and currently chairs the Environmental Health Committee and SSPC 241-Control of Infectious Aerosols. Among Dr. Bahnfleth’s ASHRAE honors are the E.K. Campbell Award of Merit for teaching, Donald Bahnfleth Environmental Health Award, Louise and Bill Holladay Distinguished Fellow Award, Andrew T. Boggs Service Award, and the F. Paul Anderson Award, ASHRAE’s highest honor. He is also a recipient of the Penn State Engineering Alumni Society World Class Faculty Award. He is a Distinguished Alumnus of the University of Illinois Department of Mechanical Science and Engineering.

Program Level:


Content Area(s):

Airborne Infection Protection for Buildings

bottom of page