Airborne infection in a fully air-conditioned hospital: I. Air transfer between rooms

Abstract

SUMMARYMeasurements have been made of the extent of air exchange between patient rooms in a fully air-conditioned hospital using a tracer-gas method.When the rooms were ventilated at about six air changes per hour, had an excess airflow through the doorway of about 0.1 m.3/sec. and the temperature difference between rooms and corridor was less than 0.5° C., concentrations of the tracer in rooms close to that in which it was being liberated were 1000-fold less than that in the source room. This ratio fell to about 200-fold in the absence of any excess airflow through the doorways. Considerable dilution took place along the corridors so that the concentration fell by around 10-fold for every 10 m. of corridor.