Airborne Infection Isolation Room – AI²

Hospitals all have these rooms; they are unique and located in so many areas of the hospital. Recently, with the pandemic, these “negative” rooms, along with so many other patient rooms, became the focus of preventing more widespread exposure. There are a lot of misconceptions about these rooms and the requirements for them. Let’s clear up many of the myths and explain how they work.

Myth #1- AI2 rooms must have an Anteroom.

False- Although it is a best practice to Don and Doff PPE, and most rooms designed do have an Anteroom, these rooms are not required* to have an extra room attached for entrance. It is completely up to the organization to have anterooms.

Myth #2- AI2 rooms are “turned on” to a negative air pressure relationship by the device located outside the room.

False- In very few rare instances, these rooms have a switch that can turn them from a Positive to Negative air pressure relationship. The switch will turn on the power to the exhaust fan and convert a normally positive pressure room into a negative pressure room. The concept is similar to a bathroom exhaust fan in most residential households. The majority of AI2 rooms are constantly in a negative air pressure relationship using an exhaust fan that is continuous 24/7. This is because the engineers and designers want to limit the ability to mistakenly place a highly communicable patient in a room and have it accidentally converted into the wrong air pressure state. Consequently, they design them to be continuous and constant states of negative pressure. These switches turn on the monitoring or door alarm, so when the room becomes positive by leaving the door open or a mechanical malfunction happens, the alarm will sound, and in some instances, the monitoring panel will turn red.

Myth#3: The requirements for Airborne Infection isolation are set forth by CMS and the Accreditation organizations.

False: The reference document in which these rooms, along with many other types of rooms including but not limited to, Operating rooms, Soiled Utility, Clean Utility, Pharmacy, and Laboratories, are detailed in the ASHRAE 170 and adopted by the Facility Guideline Institute (FGI). The construction and design of areas in hospitals have been guided by these organizations since 1947. Since this time, there have been revisions to patient room size and plumbing requirements.

Airborne Infection Isolation rooms have also changed over the years. One of the biggest changes happened in 1996/1997 when the Guideline for Design and Construction for Hospitals and Health Care Facilities published its edition and modified the air exchange rate from 6ACH to 12ACH (air exchanges per hour).

Airborne Infection isolation rooms are in many hospital departments, such as the emergency department, medical-surgical units, observation units, ICUs, PACUs, and so on. These rooms should be monitored monthly by the facilities department to ensure proper function, along with annual measurements of the exact air flow and exhaust. These measurements are known as the “Testing and air balancing report (TAB).” Often there are recommendations that come with the TAB report in which facilities and the HVAC contractor “rebalance” or adjust the system to put the system back into the design parameters. Facilities need to ensure these recommendations are implemented in a timely manner.

Many factors can disrupt the proper airflow in these specialized rooms, including leaving the door open, temperature changes in other areas of the building, programming malfunctions, and generator tests. It is important that staff from Environmental Services, Infection Prevention, the Unit/Department, and Facilities/Plant Maintenance understand the basic configuration of the systems and how these rooms function. A great time to discuss this functionality and the importance of proper functioning is during safety rounds or EOC rounds.

To learn more about Airborne Infection Isolation Rooms contact the Courtemanche and Associates Team at 704-573-4535 or email us at


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