Annals of Biomedical Engineering

, Volume 2, Issue 1, pp 106–122 | Cite as

Model studies of directed sterile air flow for hospital isolation

  • H. Buchberg
  • G. P. Lilly


Design criteria for the achievement of effective forward and reverse isolation of hospital patients, with respect to airborne contamination, was developed through model studies of directed vertical sterile air flows. The essential requirements were found to be a low turbulent intensity (of the order of 1%) air column flowing downward at 60 feet per minute and returned through floor gratings about 12 in wide running the full length of the air column along the boundaries of the protected space. The width of the protected space was found to be slightly greater than the width of the air column. A ratio of the air flow collected and recirculated to the column air flow of 1.2 to 1.3 was found to be optimal. Boundary jets or'air curtains were found to be redundant and detrimental under some circumstances.

Methods used for the model evaluation were (1) flow pattern visualization using smoke traces, (2) velocity and turbulence measurements with a hot wire anemometer, and (3) isolation effectiveness tests using CO as a gaseous tracer to simulate airborne contamination.


Smoke Turbulent Intensity Gaseous Tracer Turbulence Measurement Effectiveness Test 
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.


Unable to display preview. Download preview PDF.

Unable to display preview. Download preview PDF.


  1. Allander, C., andAbel, E. Investigation of a new ventilating system for clean rooms.Medical Research Engineering 1968,7, 28–38.PubMedGoogle Scholar
  2. Bodey, G. P., andGewertz, B. Microbiological studies of a laminar air flow unit for patients.Archives of Environmental Health 1969,19, 798–805.PubMedGoogle Scholar
  3. Buchberg, H. Improving the air environment of the operating room.Proceedings of a Symposium on Clean Room Technology in Surgery Suites, NASA 1971, Reprint Midwest Research Institute1064, 117–129.Google Scholar
  4. Gebhardt, B. Heat Transfer. New York: McGraw-Hill, 1961, 273–279.Google Scholar
  5. Huszer, R. J. Air curtains for patient isolation.Journal of the American Medical Association 1969,207, 549–551.Google Scholar
  6. Kotrappa, P., andBhanti, D. P. Smoke puff generator for room air movement studies.American Industrial Hygiene Association Journal 1968,28, 171–174.Google Scholar
  7. Kranz, P. Jet stream ventilation for extreme air cleanliness.American Society of Heating, Refrigerating and Air-Conditioning Engineers 1962,4, 37–39.Google Scholar
  8. Lidwell, O. M., andTowers, A. G. Protection from microbial contamination in a room ventilated by a unidirectional air flow.Journal of Hygiene, Cambridge 1969,67, 95–106.Google Scholar
  9. Lilly, G. P. Air curtains: patient isolation systems and the turbulent diffusion of particles.Ph.D. Dissertation 1971. School of Engineering and Applied Science, University of California. Los Angeles.Google Scholar
  10. Michaelson, G. S., Vesley, D., andHalbert, M. M. Laminar flow studied as aid in care of low resistance patients.Hospitals 1967,49, 91–106.Google Scholar

Copyright information

© Academic Press, Inc. 1974

Authors and Affiliations

  • H. Buchberg
    • 1
  • G. P. Lilly
    • 2
    • 3
  1. 1.School of Engineering and Applied ScienceUniversity of CaliforniaLos Angeles
  2. 2.School of Engineering and Applied ScienceUniversity of CaliforniaLos Angeles
  3. 3.Westinghouse Nuclear DivisionPittsburgh

Personalised recommendations