EPA and CDC Embrace ASHRAE Standard 241 in Updated Ventilation Guidance for Virus Mitigation

The EPA and CDC have updated their ventilation recommendations, now incorporating ASHRAE Standard 241, Control of Infectious Aerosols, which illustrates the importance of ventilation to decrease the transmission of respiratory viruses such as COVID-19, influenza, and RSV in populated spaces like schools, offices, and healthcare facilities. Accurate and repeatable Airflow measurement devices are instrumental in meeting these updated requirements by enabling precise control and validation of ventilation systems

Updates from the EPA and CDC

EPA’s Expanded Indoor Air Quality Guidance On November 1, 2024, the EPA released updated ventilation guidance detailing multi-layered strategies for improving indoor air quality (IAQ) and reducing virus transmission risks. Measures include:

• Increasing outdoor air.
• Enhance the ventilation to a space.
• Using advanced filtration and portable air cleaners.

The EPA emphasized that improving IAQ is critical for minimizing the health risks of airborne pollutants, especially for children, the elderly, and individuals with chronic health conditions.

CDC Endorsement of ASHRAE Standard 241 The CDC clarified that ASHRAE Standard 241 complements its Ventilation Mitigation Strategies of 5+ ACH, which can be validated with airflow measurement. The endorsement of Standard 241 aligns with its goal of reducing airborne pathogen exposure. The standard provides scientifically derived requirements for Equivalent Clean Airflow per Person (ECAi) during Infection Risk Management Mode (IRMM), establishing a baseline for safe indoor air. For more information, explore the CDC’s Frequently Asked Questions page.

Understanding ASHRAE Standard 241

ASHRAE Standard 241 provides establish minimum requirements for controlling infectious aerosols during IRMM conditions in accordance with a Building Readiness Plan when initiated. Its adoption by jurisdiction enables enforceable requirements, including:

• Built upon the minimum ventilation requirements of ASHRAE Standards 62.1, 170.1, 62.2.
• Minimum Equivalent Clean Airflow rate VECAi calculations tailored to occupancy category.
• Flexibility in using a combination of ventilation, air cleaning, and number of occupants during IRMM to achieve VECAi.

Understanding ASHRAE Standard 241

ASHRAE Standard 241 provides establish minimum requirements for controlling infectious aerosols during IRMM conditions in accordance with a Building Readiness Plan when initiated. Its adoption by jurisdiction enables enforceable requirements, including:

• Built upon the minimum ventilation requirements of ASHRAE Standards 62.1, 170.1, 62.2.
• Minimum Equivalent Clean Airflow rate VECAi calculations tailored to occupancy category.
• Flexibility in using a combination of ventilation, air cleaning, and number of occupants during IRMM to achieve VECAi.

The Role of Thermal Dispersion Airflow Measurement in Implementing Standard 241

EBTRON’s state-of-the-art airflow measurement devices are essential for compliance with ASHRAE Standard 241 by providing real-time monitoring, ensuring precise airflow control, and pathogen mitigation.

Using EBTRON Solutions:

• Outdoor Air Ventilation Monitoring—Validate and maintain outdoor air delivery rates in normal mode and IRMM to meet dilution requirements.
• Clean Airflow Validation—Measure airflow through induct air cleaning systems to confirm that they have an equivalent clean airflow rate (VACS) and are compliant with IRMM needs.
• Airflow Measurement – Measures supply and return airflow quantities for the ventilation zone.
• Pressurization Control – Track airflow to Maintain pressurization for the building and spaces during normal and IRMM modes.
• Functional Performance Tests (FPTs) – Validate outdoor air, supply, return, and VACS rates and pressure tracking in normal, IRMM, Economizer, and DCV modes.

For further details, consult the EPA’s updated guidance on ventilation and the CDC’s FAQ on ASHRAE Standard 241. Enhance your facility’s resilience to airborne pathogens by investing in EBTRON airflow measurement solutions and meeting ASHRAE Standard 241.