Changes in COVID Guidance in Regard to Building Ventilation


Building ventilation requirements came to the forefront of indoor environmental quality concerns during the COVID-19 pandemic. Researchers worldwide asked, “How do we promote healthier indoor environments through effective and efficient ventilation and filtration?”

The pandemic was undoubtedly an eye-opener on the importance of mechanical ventilation. The threat helped building managers better understand the performance, maintenance, and limitations of their existing ventilation systems.

On the regulation side of the puzzle, we may soon see updates to existing requirements. In this article, we will consider some of those possibilities.

Building Ventilation Research

Initial recommendations from public health agencies and organizations focused on interim measures to optimize the supply of air into occupied spaces. Most were concerned about maximizing outdoor air intake and upgrading air filtration to the extent feasible. Other recommendations specified the number of air changes per hour to effectively remove airborne droplets — especially in classroom settings.

ASHRAE’s Epidemic Task Force published a tool in 2021 to calculate the equivalent outdoor air from a combination of existing and supplemental technologies to achieve a certain number of “clean air changes” to quickly and effectively “flush” air and reduce airborne particulates. The tool, however, did not factor in the number of occupants of specific floor areas and functional spaces, which is the primary basis of the minimum required quantity of outdoor air following ASHRAE standard 62.1 “Ventilation for Acceptable Indoor Air Quality.” This gap was addressed by standard 241 “Control of Infectious Aerosols” which was released in June 2023 and includes an equivalent clean air per person parameter.

Prior to the release of ASHRAE standard 241, the Federation of European Heating, Ventilation and Air Conditioning Associations (REHVA) published its “Health-based Target Ventilation Rates and Design Methods.” That proposal accounts for the number of occupants among other health-specific variables to calculate health-based target air changes for different spaces.

The CDC in its recent “Ventilation in Buildings” guideline adopted five air changes and suggested MERV 13-rated filters as a minimum target for building spaces. The guideline also addressed energy costs and flushing outside occupancy periods. The CDC guideline aligns with the federal EPA “Clean Air Building Challenge” recommendations. The EPA’s challenge also recommends creating an IAQ Action Plan as a first step, which includes inspection and maintenance of HVAC systems.

Similarly, ASHRAE standard 241 includes an “Infection Risk Management Mode” which is activated when enhanced protection is needed during periods of active disease transmission. The standard also calls for a building readiness plan to verify the proper operation of ventilation systems.

Collectively, these new recommendations are likely to form the basis of future code-enforceable regulation and are already finding their way into grant funding requirements and project specifications. Building managers would be wise to begin adapting to this changing landscape. In the meantime, these concepts can help document the proactive measures taken by operation and maintenance personnel to reduce the risk of outbreaks in buildings and minimize occupant concerns and potential liabilities.

COVID gave us plenty to think about, and for building managers, the pandemic provided additional insight to best manage air quality to help protect occupants from airborne disease.

Implementing Solutions

To tackle the challenges brought by this changing landscape, FACS has developed a Healthy Building Framework. It is an integrated proactive indoor environmental quality management program for buildings — whether commercial, educational, governmental, healthcare, industrial, or other usage types.

The FACS framework covers the evaluation and identification of hazards, control measures for enhanced protection, and the verification and validation of building systems. It provides a mechanism for integrating existing preventative maintenance programs along with new guidelines into a scalable model that can be expanded over time and serve as a basis for supporting 3rd party building certification programs. This framework allows building managers and maintenance personnel to demonstrate and communicate the actions they are taking to ensure a healthy environment to occupants and other stakeholders.

For more information about the FACS’ Healthy Building Framework or to get up-to-date advice on building ventilation and indoor environmental quality issues, call us at (888) 711-9998 or use our online contact form to schedule a discussion.