Interpersonal Transport of Droplet Nuclei among Three Manikins in a Full-Scale Test Room

This study focuses on occupants’ exposure of droplet nuclei exhaled by one susceptible in a full-scale test room. Three breathing thermal manikins are standing in the middle of room and both the process in the microenvironment and in the macroenvironment are considered. A diffusive ceiling has been installed to induce fresh air without generating sensible drafts in an occupied zone with fully mixing flow. The exposures of two target manikins to the droplet nuclei exhaled by one susceptible manikin were measured. Tracer gas N2O was used to simulate droplet nuclei. Comparisons on different mutual distances and facing angles were conducted. It is found that the exposures of target manikins are not close to the results of previous two-manikin studies. During the measurements, dynamic exposures are measured, and fluctuation of targets’ exposures was observed during the experiment. It is found that instant high exposure exists even the average exposure is low. Two symmetrically located target manikins have different exposures of droplet nuclei exhaled by one susceptible manikin. The exposures of two target manikins are compared between mutual distances 0.5 m [1.6 ft.] and 0.8 m [2.6 ft.], respectively. The facing angles of the target manikins did not make a significant impact on the exposure from 60° to 90°