Localized Ventilation Method for Providing Clean Air to Hospitalized Patients

Three novel air terminal devices (ATDs) for localized ventilation were designed (ATD with perforated inner plate, ATD with honeycomb diffuser, and ATD with lobbed nozzle). The ability of the ATDs to provide clean air to the breathing zone of a person lying in a hospital bed was studied. Experiments were performed in a simulated full-scale hospital patient room.

A thermal manikin was used to simulate a patient. The ATD was located above the head of manikin. Heated dummy simulated a doctor standing beside the bed. Tracer gas was used to simulate contaminated air exhaled by the doctor. The supply and the exhaust flow rates were controlled at 15.3 L/s and 14.8 L/s, respectively.

The supply air temperature and room temperature were kept at 23 °C and 25.3 °C, respectively. Increase of the supply air speed resulted in a cleaner air supply to the breathing zone but also increased the risk of draught. The ATD with a lobbed jet nozzle was able to reduce contaminants by more than half in the breathing zone and to provide the lowest draught risk at the face.

This ATD is a better solution to supply clean air in practice comparing to the other two ATDs.