Conclusions that can be drawn from the study include:

  • Low exhaust outperforms other exhaust locations in terms of particle removal and number of particles remaining around a bed.
  • Increasing ventilation flow from 12 to 16 ACH generally helps to remove particles from an isolation room (except in cases of high exhaust and a lying patient coughing), but not necessarily a breathing zone.
  • The number of particles in a bathroom resulting from a cough in a main room is dependent on air-current particle distribution and bathroom location.

Standard operating procedures are extremely important and should be developed as part of the planning process, with consideration given to facility purpose and features.


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2) Fennelly, K.P., Martyny, J.W., Fulton, K.E., Orme, I.M., Cave, D.M., & Heifets, L.B. (2004). Cough-generated aerosols of Mycobacterium tuberculosis: A new method to study infectiousness. American Journal of Respiratory and Critical Care Medicine, 169, 604-609.
3) Fitzgerald, D., & Haas, D.W. Mycobacterium tuberculosis. In: Mandell, Douglas, and Bennett's principles and practice of infectious diseases (6th ed.). (2005). Philadelphia: Churchill Livingstone.
4) Hoppe, P. (1981). Temperature of expired air under varying climatic conditions. International Journal of Biometeorology, 25, 127-132.
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Director of the National Institutes of Health's (NIH's) Division of Technical Resources, Farhad Memarzadeh, PhD, PE, consults on matters related to biocontainment and medical research laboratories around the world. He has written four books and more than 60 scientific research and technical papers published in peer-reviewed journals and been a guest and keynote speaker for more than 50 international scientific and engineering conferences and symposia. Deborah E. Wilson, DrPH, CBSP, is director of the NIH's Division of Occupational Health and Safety and founder and director of the National Biosafety and Biocontainment Training Program. She is a career U.S. Public Health Service Commissioned Officer. Krishnan Ramesh, PE, is a managing principal of Affiliated Engineers Inc. He has extensive experience planning, engineering, and designing biological and chemical research laboratories and vivaria nationwide and is a technical contributor to the NIH Design Requirements Manual for Biomedical Laboratories and Animal Research Facilities.


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