Medical Air Solutions, Inc.

Airborne Infectious Isolation (AII) Room Pressure Monitoring

There has been some question about the need for monitoring negative pressure in infectious isolation rooms recently.  Mr. George Mills, Assistant Director of Engineering for the Joint Commission on Accreditation of Healthcare Organizations (JCAHO), has stated that existing AII rooms in use before January 1, 2003, are, in fact, grandfathered when considering the requirement for having a permanent pressure monitor unless the room is being renovated or is newly constructed.  An earlier issue of Current Comments stated that JCAHO required room pressure monitors and was not grandfathered.  We apologize for that error which was due to a miscommunication between JCAHO and MAS.

JACHO has adopted the American Institute of Architects (AIA) 2001 “Guidelines for Design and Construction of Hospital and Health Care Facilities” into their Environment of Care standards and has stated that renovated or newly constructed rooms must have a room pressure monitor installed that provides a numerical value and can sense flow direction.  The issuance of a violation by JCAHO is predicated on whether there is a state or local code stating that a monitor must be installed.  As of this writing, the AIA standards are adopted in their entirety into building codes by eight (8) states, a vast majority of the standards by thirty (30) states and partly by the remaining ten (10) states.

Mr. Mills stated that in many states, and also in some county/parish and local governments, a room pressure monitor is required as stated in building codes.  You should contact your state and local building standards agencies for further information and clarification.

There are other agencies/institutions that comment on room pressure monitors.  They are:

Francis J. Curry National Tuberculosis Center – This institution is funded by the Centers for Disease Control and Prevention (CDC) and the California Department of Health and is considered to be the CDC’s engineering group in the design of areas for airborne infectious isolation.  In their document “Isolation Rooms: Design, Assessment, and Upgrade”, they state: 

“The most reliable way to monitor negative pressure is to install a permanent electronic room pressure monitor as part of the construction project. When properly selected and installed, a room pressure monitor can provide continuous qualitative and quantitative confirmation of negative pressure across a room boundary. This is in contrast to routine periodic smoke testing, which merely provides an indication of directional airflow at the moment of testing.”

 This document was created in 1999 and is slightly outdated but does contain valuable information on the design, upgrading and assessment of AII rooms.  Most hospitals that wish to be proactive in designing or upgrading a room or rooms for AII use could benefit from the information in this document.  You may view this document at: http://www.medicalairsolutions.com/techref/cdc/fjc_isolation_rooms.htm

Occupational Safety and Health Administration (OSHA) – The OSHA regulation CPL 2.106 (1994) recommends a permanent room pressure monitors and states:

“Pressure-measuring devices should sense the room pressure just inside the airflow path into the room (e.g., at the bottom of the door).  Unusual airflow patterns within the room can cause pressure variations; for example, the air can be at negative pressure at the middle of a door and at positive pressure at the bottom of the same door.  If the pressure-sensing ports of the device cannot be located directly across the airflow path, it will be necessary to validate that the pressure across the flow path.

Pressure-sensing devices should incorporate an audible warning with a time delay to indicate that a door is open. When the door to the room is opened, the negative pressure will decrease.  The time-delayed signal should allow sufficient time for persons to enter or leave the room without activating the audible warning.”

American Institute of Architects (AIA) – The 2001 “Guidelines for Design and Construction of Hospital and Health Care Facilities” part 7.2.C7. states:

“Rooms shall have a permanently installed visual mechanism to constantly monitor the pressure status of the room when occupied by patients with an airborne infectious disease.  The mechanism shall continuously monitor the direction of airflow.”

 When a renovation is planned, the new standards should be incorporated into the work that is to be performed.  Part 1.3.A. states in part:

“When renovation or replacement work is done within an existing facility, all new work or additions, or both, shall comply, insofar as practical with applicable sections of this Guidelines and with the appropriate parts of NFPA 101, covering New Health Care Occupancies.  Where major structural elements make total compliance impractical or impossible, exceptions should be considered.”

State and Local Departments of Health – These government agencies also have engineering standards that may apply to present AII rooms and those that are to be renovated and for new construction.  Contacting your state and local health departments may be advisable if there are questions concerning compliance with building codes.

The CDC’s Healthcare Infection Control Practices Advisory Committee (HICPAC) also recommends the use of permanently installed monitors.  Mr. Mills of JCAHO stated that they will review all CDC, and divisions of the CDC, documents in relation to room monitoring for future consideration.

In summary, it is prudent to monitor the pressure and airflow direction in AII rooms on a continuous basis.  The vagaries of flows in HVAC systems can change during the course of even one day and can cause a negative pressure room to become a positive pressure room.  While local audible and visual alarms on these units is not required, common sense would indicate that knowing that air could be migrating from an AII room into the hallway could be difference between keeping staff and visitor safe or becoming infected with an airborne infectious disease.  Feel free to call us at 800-645-1059 if there are any questions or concerns relating to this topic.

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