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U.S. Department of Health and Human Services


Core Curriculum on Tuberculosis, 2000

Chapter 8
Infection Control in Health Care Settings

Engineering Controls

The second level of the hierarchy is the use of engineering controls to prevent the spread and reduce the concentration of infectious droplet nuclei.  Engineering controls are based primarily on the use of adequate ventilation systems; these may be supplemented with high-efficiency particulate air (HEPA) filtration and ultraviolet germicidal irradiation (UVGI) in high-risk areas. These strategies are designed to reduce the concentration of infectious droplet nuclei in the air, prevent the dissemination of droplet nuclei throughout the facility, or render droplet nuclei noninfectious by killing the tubercle bacilli they contain.

Inpatient Settings. In isolation rooms, ventilation systems are necessary to maintain negative pressure and to exhaust the air properly. Isolation rooms should be monitored daily when in use to ensure the negative pressure is maintained. Isolation room doors should be kept closed, except when patients or personnel must enter or exit the room, in order to maintain negative pressure. Ventilation systems can also be designed to minimize the spread of TB in other areas of the health care facility.

HEPA filters can be used in ventilation systems to remove droplet nuclei from the air. These filters can be installed in ventilation ducts to filter air for recirculation into the same room or recirculation to other areas of a facility. The effectiveness of portable HEPA filtration units has not been adequately evaluated. All HEPA filters must be carefully installed and meticulously maintained to ensure adequate function.

UVGI, or ultraviolet lighting, may kill M. tuberculosis contained in droplet nuclei. Because exposure to ultraviolet light can be harmful to the skin and eyes, the lamps must be installed in the upper part of rooms or corridors or placed in exhaust vents.

Outpatients settings. In outpatient settings, such as medical offices, that provide care to populations at high risk for TB, the use of engineering controls may be appropriate.


Released October 2008
Centers for Disease Control and Prevention
National Center for HIV/AIDS, Viral Hepatitis, STD, and TB Prevention
Division of Tuberculosis Elimination -

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