Keep an Eye on Ventilation Standards at Clinics

Infection Control TodayInfection Control Today, April 2021 (Vol. 25 No.3)
Volume 25
Issue 03

Beware the loophole. Many clinics are often classified as office space, not health care buildings, so they do not have adhered to ventilation standards.

Health care continues to extend beyond the traditional hospital setting. Recent decades have seen the growth of stand-alone clinics, ancillary clinics to hospital systems, clinics in retail pharmacies, urgent care centers,1 and even hybrid clinic–primary care physician offices. But with this growth comes concern over whether these clinics meet safety standards.2

Investigators with the University of Texas wanted to find out how well clinics are ventilated. “Overall, the results indicate that the evaluated outpatient clinics did not fully meet health care ventilation standards as listed in the Standard 170 for Ventilation in Health Care Facilities,” the research team concluded in a recent preprint study in the American Journal of Infection Control.3 The standard, which establishes the parameters4 for ventilation of health care facilities, is set forth by 3 organizations: the American National Standards Institute, the American Society of Heating, Refrigerating and Air-Conditioning Engineers, and the American Society for Health Care Engineering.

“Lower than standard air changes per hour [ACH] were observed and could lead to an increased risk of spread of diseases when conducting advanced procedures and evaluating persons of interest for emerging infectious diseases,” the study states.

Investigators argue that this is an especially important issue as the coronavirus disease 2019 (COVID-19) pandemic continues. “These findings are pertinent during the SARS-CoV-2 pandemic, as working guidelines are established for the health care community.”

Procedures such as bronchoscopy, tracheal intubation, nebulizer treatment, colonoscopies, suction during intubation, and endotracheal aspiration can all generate airborne microorganisms, the investigators note. Those microorganisms can also be generated by simple everyday things like coughing or sneezing, talking, or even just breathing.

When it comes to clinics, there is a loophole that means ventilation systems do not necessarily have to abide by Standard 170. Outpatient clinics usually have fewer than 5 patients who are incapable of taking care of themselves in case of an emergency. That means clinics are often classified as businesses.

“As health care specific building codes would not normally pertain to business occupancy, it is unclear if the health care ventilation standards are integrated into outpatient clinic design or lease agreements in these types of buildings,” the study states.

Investigators looked at ventilation in 105 rooms at 22 outpatient clinics geared toward different specialties. The clinics are affiliated with a medical practice group in a major city.

They used the Gammaitoni-Nucci model to measure ventilation and estimate disease transmission rates in the buildings. “When compared to Standard 170, 10% of clinic rooms assessed did not meet the minimum requirement for general exam rooms, 39% did not meet the requirement for treatment rooms, 83% did not meet the requirement for aerosol-generating procedures, and 88% did not meet the requirement for procedure rooms or minor surgical procedures,” the study states.

Investigators used a smoke tube to determine how well the ventilation systems worked. They would puff out smoke at the height of the health care worker standing in the center of a room and count how many seconds it took for the puff to dissipate. They placed the rooms into different categories.

“Medical office building” was defined as the medical or dental clinic being the only occupant in the building, the study states. “Shopping center” meant the clinic was attached to nonmedical commercial buildings. “Stand-alone clinic” was defined as the clinic building not being attached to any other buildings. “Building age, number of floors, and total clinic square footage was obtained from the building lease management office, websites or clinic lease agreements.”

Investigators argue that good ventilation, along with the proper use of personal protective equipment, are the best means to thwart disease transmission in a health care setting.

“An additional concern is the increasing role outpatient clinics play in response to evaluating patients during outbreaks of emerging infectious diseases,” the study states. “These responses commonly recommend that patient evaluations be conducted in a negative pressure isolation room that is required to have 12 ACH. When working in outpatient clinic space with a lower than minimum standard ACH, the ability to safely perform assessments and patient care may inadvertently increase the risk to workers and the potential spread of the disease within the clinic.”

ACH were lower than the standard in all the buildings that investigators observed, but newer one-story buildings had higher ACH than
older buildings.

“Lower ACH in outpatient clinic rooms conducting more advanced procedures can lead to an increased risk of spread of infectious diseases,” the study states. “We echo the concern that ventilation standards are not being met and should be integrated into clinic design and reaffirm that there are challenges in compliance with ventilation standards in nonhospital settings…. Factors such as national ventilation standards, intended use, and services provided should be considered when designing and leasing all health care settings. These findings are pertinent during the SARS-CoV-2 pandemic as we establish working guidelines for the health care community.”


  1. 2019 Benchmarking Report. Urgent Care Association. Accessed February 2, 2021.
  2. Retail Health Clinics: State Legislation and Laws. National Conference of State Legislatures. November 2011. Updated August 1, 2017. Accessed January 30, 2021.
  3. King KG, Delclos GL, Brown EL, et al. An assessment of outpatient clinic room ventilation systems and possible relationship to disease transmission. Am J Infect Control. Published online January 20, 2021. doi:10.1016/j.ajic.2021.01.011
  4. Steiner C. COVID-19 pandemic proved the importance of airflow in buildings. Infection Control Today. Published online December 18, 2020.

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