An evaluation of hospital special-ventilation-room pressures

OBJECTIVE: To quantitate the magnitude and consistency of positive (airflow out) and negative (airflow in) hospital special-ventilation-room (SVK) air flow DESIGN: A room-pressure evaluation was conducted during two seasons on a to tal of 18 rooms: standard rooms, airborne infection isolation rooms, and pr otective environment rooms. The pressures were measured using a digital pre ssure gauge-piezoresistive pressure sensor that measured pressure different ials. 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 press ure differential, with an average of -0.2 Pa (median, -0.2 Pa), and an inte rquartile 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 fluctua tion 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, whi ch may have been influenced by room architectural differences (sealed vs un sealed); heating, ventilation, and air-conditioning zone interactions; and stack effect. CONCLUSION: The pressure variations noted in this study, which potentially affect containment or exclusion of contaminants, support the need for stand ardization of pressure requirements for SVRs. To maintain consistent pressu re levels, creating an airtight seal and continuous pressure monitoring may be necessary (Infect Control Hosp Epidemiol 2001;22:19-23).