An experimental study on exposure risks in a double-bed patient room with different air distribution methods

¹ Department of Energy and Mechanical Engineering, Aalto University, Finland
² Halton Oy, Finland
³ Granlund Oy, Finland

^* Corresponding author: This email address is being protected from spambots. You need JavaScript enabled to view it.

Abstract

Hospital environments have higher requirements for infection control on the health of occupants. This study aims to compare air distribution effects on reducing healthcare exposure risks in a simulated double-bed patient room, focusing on key parameters such as airflow patterns, heat gain, air distribution methods, and exhaust locations. In the experimental study, tracer gas (SF6) was used to simulate airborne aerosols from an infected patient by a thermal breathing manikin. A four-way nozzle diffuser (ND) for mixing ventilation and a dynamic protective airflow panel system (DPP) for personalized ventilation were utilized and compared as two different air distribution methods. The results showed that cases with a high airflow rate of 80 L/s decreased the concentration level, from an average of 22.8-26.5 ppm to 10.5-12.3 ppm compared to conditions with a lower rate of 40 L/s. In addition, the standard deviation (SD) of concentration was 3.5 and 1.1 ppm using DPP with 80 L/s airflow rate under a heat gain level of 17 W/m² and 29 W/m², presenting a stable concentration with high heat gains. The dilution ratios for ND and DPP fluctuated at the airflow rate of 80 L/s. While with low airflow rate of 40 L/s, they had no significant differences in removing particles. Exhaust locations did not affect contamination removal in the double-bed patient room.