title: An evaluation of hospital special-ventilation-room pressures.
abstract: OBJECTIVE
  To quantitate the magnitude and consistency of positive (airflow out) and negative (airflow in) hospital special-ventilation-room (SVR) airflow.
  
  
  METHODS
  A room-pressure evaluation was conducted during two seasons on a total of 18 rooms: standard rooms, airborne infection isolation rooms, and protective environment rooms. The pressures were measured using a digital pressure gauge-piezoresistive pressure sensor that measured pressure differentials. With doors closed, the rooms were measured a minimum of 30 times each for a cooling season and a heating season.
  
  
  RESULTS
  The standard rooms showed the least amount of variability in pressure differential, with an average of -0.2 Pa (median, -0.2 Pa), and an interquartile range (IQR) of 0.4 Pa. Airborne infection isolation rooms showed more variability in pressure, with an average of -0.3 Pa (median, -0.2 Pa) and an IQR of 0.5 Pa. Protective environment rooms had the greatest fluctuation in pressure, with an average of 8.3 Pa (median, 7.7 Pa) and an IQR of 8.8 Pa. Dramatic pressure changes were observed during this evaluation, which may have been influenced by room architectural differences (sealed vs unsealed); heating, ventilation, and air-conditioning zone interactions; and stack effect.
  
  
  CONCLUSIONS
  The pressure variations noted in this study, which potentially affect containment or exclusion of contaminants, support the need for standardization of pressure requirements for SVRs. To maintain consistent pressure levels, creating an airtight seal and continuous pressure monitoring may be necessary.
authors.affiliation: Division of Environmental and Occupational Health, School of Public Health, University of Minnesota, Minneapolis 55455, USA.
authors.forename: N
authors.initials: N
authors.lastname: Rice
authors.forename: A
authors.initials: A
authors.lastname: Streifel
authors.forename: D
authors.initials: D
authors.lastname: Vesley
mesh_terms: D002138:Calibration; D006749:Hospital Design and Construction; D006761:Hospitals; D006801:Humans; D017053:Infection Control / Q000379:methods*; D011312:Pressure; D012016:Reference Values; D014691:Ventilation