ASHRAE Building Standard 241 Targeting Infectious Aerosols to Improve the Air Quality of Indoor Environments

Editor’s note: The following post is written by guest blogger Dave Becattini, Vice President, LifeAire Systems. In September 2022, the Pennsylvania C-PACE program was expanded to include Indoor Air Quality (IAQ) as an eligible measure for C-PACE financing. This piece discusses an important new standard from ASHRAE related to IAQ. PEA is not endorsing or recommending LifeAire or its products.

ASHRAE released Standard 241, its first-ever standard for “Control of Infectious Aerosols.” This standard “establishes minimum requirements to reduce the risk of disease transmission by exposure to infectious aerosols in new buildings, existing buildings, and major renovations.”

The key driver for the development of Standard 241, according to Dr. Bill Banfleth, the Chairman of the ASHRAE committee that created the standard, was “discussion between ASHRAE and the White House COVID-19 Response Team about the need for new and better IAQ (indoor air quality) standards. ASHRAE was encouraged to take the lead in developing a new standard for control of airborne pathogens.” For those less familiar with ASHRAE guidelines, they aren’t mandates but they are generally accepted throughout the U.S. and Canada as the gold standard for HVAC.

This is a particularly important and welcome step forward; having ASHRAE’s recognition of certain key requirements for air cleaning technology, such as single pass pathogen remediation and rigorous third-party testing under conditions similar to where the devices will be used. Single pass means the remediation is virtually instantaneous. Pathogens are killed on the first pass through the HVAC system. Most technologies take 30 – 60 minutes to kill pathogens such as COVID 19 so they allow them to recirculate through the HVAC system multiple times therefore distributing them throughout a building. Single pass effectiveness and real-world testing are essential for ensuring a technology’s effectiveness in the field. And, full disclosure, these elements have been a cornerstone of my company, LifeAire Systems, since our founding over 10 years ago.

Standard 241 also establishes the concept of “Equivalent Clean Airflow” through filtration and/or air cleaners to purify the recirculating air within a facility. This reduces the need to bring in additional outside air which is very energy intensive and costly.

Also of note is the call for previously installed air cleaning systems to comply with the testing requirements of this standard after January 1, 2025. For many, this will prompt a re-examination of their air purification strategies and likely require changes or additions to achieve full compliance. This is welcome news for many facilities exploring how they can build on their existing IAQ strategies or implement a new one to reach the high air purity requirements of Standard 241 for both new and retrofit applications.

These new requirements with more focus on clean airflow are a welcome addition in the post-COVID pandemic era, where air quality and protection from the transmission of airborne diseases has moved into the mainstream and remains a high priority. LifeAire Systems applauds the efforts of ASHRAE in releasing this new standard and supports ASHRAE’s hope for the standard’s future role in helping to save lives and minimize disruption to society of airborne diseases.

About: LifeAire Systems has patented air purification technology. This high-performing technology is proven to effectively eliminate airborne chemical and biological pathogens in a single pass. For more information, please visit Dave Becattini can be contacted at