COVID-19 Pandemic Proved Importance of Airflow in Buildings

Infection Control TodayInfection Control Today, March 2021 (Vol. 25 No. 2)
Volume 25
Issue 02

Officials at the Children’s Hospital of Philadelphia have the ability to convert several floors into airborne infection isolation rooms (AII), or more commonly termed negative pressure rooms, with the flip of a switch.

The airflow in your facility may have been overlooked prior to coronavirus disease 2019 (COVID-19) but that has changed. When it comes to infection control and prevention, it’s time to focus on this critical element for patient and provider safety. Take a moment to consider where the air supply directly overhead comes from. Infectious agents or suboptimal environmental conditions, perpetuated by the air supply, will exacerbate infections.

To manage a highly transmittable disease such as COVID-19, organizations have used altered airflows, or more specifically negative pressure, within their facilities to increase air exchanges and optimize fresh outdoor air. I first became involved in such a project while serving at a skilled nursing facility. To manage the oncoming crisis and uncertainty associated with admissions, quarantine procedures, and hospital capacities, I worked with Shelly Miller and a group of colleagues at the University of Colorado to convert a rehabilitation hallway into a negative pressure space. We performed computational fluid dynamics and particle-based modeling to test containment. The isolation space was successful both in our model and in practice at controlling transmission between residents and staff.1 Due to the cancelation of elective surgeries and the subsequent pause in rehabilitation services, the negative pressure space provided an important revenue stream and community resource for older people requiring skilled COVID-19 nursing care.

When the Boston Globe recorded Steward Health Care’s preparations at Carney Hospital in Dorchester, Massachusetts, to make the institution the nation’s first dedicated coronavirus care center, Steward stressed the transformation of a floor into negative pressure.2 Carney designated a team of doctors and an operating room within the coronavirus care center to prevent transmission to the broader hospital population. But it was the negative pressure and separate airflow that was arguably the largest factor making it a “hospital within a hospital.”

Outbreaks such as the Ebola virus disease of 2014-2016 encouraged the thinking behind building designs to include the capability of achieving negative pressure over large areas. Engine ers at Children’s Hospital of Philadelphia foresaw a looming pandemic and designed their buildings with the ability to respond. Hospital officials can convert several floors into airborne infection isolation (AII) rooms, more commonly termed negative pressure rooms, with the flip of a switch. In the most recent pandemic, this innovation and foresight has proved to be tremendously beneficial.

According to Rachel McCarthy, vice president of plant operations at Children’s Hospital of Philadelphia, the hospital’s newest design has the ability to convert 2 floors, 3 wards, and more than 150 rooms to AII rooms. The building management system (BMS) uses computer software to adjust the mechanical and electrical equipment throughout the building to achieve the desired results. At the request of administration and the infection control and prevention team, this system can be turned on to achieve the desired airflows throughout the building. But this requires the necessary infrastructure. Controls, equipment, and sensors need to be installed and building management must be trained. I’m convinced these improvements should be a future investment in public health that should not only be in hospitals but in other health care settings, such as skilled nursing facilities. As McCarthy puts it, “Managing a pandemic without a problem requires [personal protective equipment], testing, and negative pressure,” a 3-pronged approach.

Smart Buildings

Nick Clements, PhD, is a lead consultant at WSP USA, a globally recognized professional services firm specializing in infrastructure, and an expert in building technology systems. He envisions a smart building with integrated infection controls. In a recent conversation, he outlined some innovations and challenges currently being explored in new building design across transportation, manufacturing, and health care. “Smart building,” or building automation, is used to denote buildings with integrated controls and data collection. This often involves the automation of multiple interrelated systems such as heating, ventilation, and air conditioning, electrical, lighting, access control, and security systems through a BMS. Imagine taking this a step further where patient data and health care provider information are integrated into the building. Clements discussed a scenario in which future infections would be identified rapidly before they could spread. This could be done through a BMS that contained integrated patient data and diagnostic technologies employed in monitoring airflows.

For example, microfluidic systems and biosensors, used for clinical diagnostic purposes, could be integrated into a building system to provide clinical data. One type, the local evanescent array coupled (LEAC) biosensor, uses optical immunoassay sensors that permit the detection of up to hundreds of target biomolecules and viruses.2 The chemical and biological engineering program at Colorado State University has a group focused on this technology. These sensors require no reagents, are low cost, and operate as a lab-on-a-chip with integrated circuits.3,4

These diagnostic tools could alert building occupants and confirm the spread of an infection. An integrated BMS that contains pressure monitors could also adjust pressure zones and air supply, further protecting a region within a hospital. When combined with patient and health care tracking, this information could be used to identify the source of an infection. According to Clements, “the challenges of a smart building require the whole organization to innovate.”

In a truly integrated BMS, many monitors and systems need to feed back into the control platform. Currently, these systems are often standalone or siloed in a BMS and require a control engineer to integrate the data—a significant burden. A cloud-based system could alleviate difficulties in staffing information technology technicians and data management scientists.

The current COVID-19 pandemic will spur innovation most likely in the direction of vaccines, testing, and airflows. When it comes to airflows, keep an eye on ANSI/ASHRAE/ASHE Standard 170-2017, which currently details guidelines for environmental controls within health care facilities. The standard, which establishes the parameters for ventilation of health care facilities, will need to guide decisions between infection control teams and building management. Standard 170-2017 allows retrofits to be made to convert standard patient rooms into AII facilities. Infection control teams should be in discussion with facility management on these possibilities if we are to expect any future improvement in managing infectious agents similar to COVID-19. I expect the future holds some exciting building management tools for the infection control preventionist. p

CEDRIC STEINER is a licensed nursing home administrator in Lancaster County, Pennsylvania. Contact him at to learn more about the use of negative pressure for immediate or future COVID-19 relief.


  1. Miller SL, Mukherjee D, Wilson J, Clements N, Steiner C. Implementing a negative pressure isolation space within a skilled nursing facility to control SARS-CoV-2 transmission. Am J Infect Control. Published online October 3, 2020. doi:10.1016/j.ajic.2020.09.014
  2. Ellement, JR. Carney Hospital in Dorchester establishing COVID-19 treatment center. The Boston Globe. Updated March 17, 2020. Accessed November 12, 2020.
  3. Yan R, Kingry LC, Slayden RA, Lear KL. Immunoassay demonstration using a local evanescent array coupled biosensor. Proc SPIE 7559, Optical Fibers and Sensors for Medical Diagnostics and Treatment Applications X, 75590D. February 24, 2010.
  4. Bioanalytical Microfluidics Program. Colorado State University. Accessed November 20, 2020.
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