Hosted by Airmid Healthgroup in partnership with ASHRAE Ireland
On October 22, 2025, Airmid Healthgroup was honoured to welcome Professor Chandra Sekhar, Ph.D., Distinguished Lecturer from the National University of Singapore, for a special seminar on ASHRAE Standard 241: Control of Infectious Aerosols. The event, held in partnership with ASHRAE Ireland, brought together professionals from across the indoor air quality (IAQ), HVAC, and healthy buildings sectors for an afternoon of collaboration, discussion, and knowledge exchange.
Exploring ASHRAE Standard 241
Professor Sekhar’s presentation provided an in-depth exploration of ASHRAE Standard 241-2023, the first health-based standard developed by ASHRAE in response to lessons learned from the SARS-CoV-2 pandemic. The standard defines minimum requirements for controlling infectious aerosols in buildings, marking a major milestone in global efforts to strengthen infection control through ventilation and air cleaning.
Attendees gained valuable insights into key components of the standard, including:
- Infection Risk Management Mode (IRMM) — a new operational framework that can be activated during periods of elevated risk to minimize airborne infection transmission.
- Building Readiness Plan (BRP) — a preparedness strategy that ensures building systems can transition into IRMM when needed.
- Equivalent Clean Airflow (ECA) — a method for determining the theoretical flow rate of pathogen-free air needed to achieve target air quality levels within the breathing zone.
Professor Sekhar also discussed practical applications, including examples from his team’s work creating “isolation rooms” in residential settings using natural ventilation and simple fan configurations to enhance airflow and reduce transmission risk.
Airmid Healthgroup’s Role in Standards Implementation
The event sparked thoughtful discussion among attendees about the practical steps needed to align building operations, ventilation, and air cleaning technologies with the new standard. Topics such as upper-room UVGI, portable air cleaners, filtration efficiency, and occupant-centred design were explored in the context of implementing ASHRAE 241 in real-world environments.
“Events like this reflect our commitment to advancing the global conversation on infection control, IAQ, and evidence-based healthy building design,” said Dr. John Ryan, CEO of Airmid Healthgroup. “We were delighted to host Professor Sekhar and ASHRAE Ireland as part of our shared mission to make buildings healthier and more resilient.”
As a GLP- and ISO/IEC 17025-accredited contract research laboratory, Airmid Healthgroup supports the implementation of ASHRAE Standard 241 and related standards through its advanced aerobiology chambers, infectious aerosol testing, and environmental simulation facilities. These capabilities enable the testing and validation of air cleaning systems, filters, and HVAC technologies designed to improve indoor environmental quality (IEQ) and public health outcomes.
By facilitating seminars such as this, Airmid Healthgroup continues to encourage dialogue and collaboration between researchers, engineers, and product developers committed to the science of clean air and healthy building design.
Acknowledging Our Speaker and Partners
Airmid Healthgroup extends sincere thanks to Professor Chandra Sekhar for his engaging and thought-provoking presentation, and to ASHRAE Ireland for their continued partnership in promoting best practices in indoor environmental control.
Related Links on ASHRAE 241
Internal links:
- About ASHRAE Standard 241 Testing and Evaluation Services
- Aerobiology Chamber Testing Capabilities for ASHRAE Standard 241 or “ASHRAE 241”, infectious aerosols
- Air Cleaning and Filtration Research at Airmid Healthgroup
- Aerobiology testing services for AHAM AC-5 or “microbial or mCADR”
External references:
