The global pandemic caused by the novel coronavirus (COVID-19) has caused many businesses and institutions around the world to implement new safety measures to minimize the spread of the virus. At Auburn University, along with wearing face coverings, to help protect faculty, staff, and students, physical barriers in high traffic areas were installed to provide further protection in the case of an inadvertent sneeze or cough. Physical barriers are recommended by the Center for Disease Control (CDC), however guidelines on the size or shape are not available. Auburn Makes, a group that provides makers a path to transform ideas into reality, worked with the Auburn University Department of Aerospace Engineering to determine if the size and shape of various partitions influences their effectiveness.

For this study, three partitions were constructed with shield angles of 0°, 45°, and 90° as seen in Figure 1. It was assumed that the partitions would be placed on a tabletop with a person sitting and facing the shield with their mouth located 14 inches above the tabletop. To study the effectiveness of the shield, a jet of smoke was used to emulate a cough and the angle of the jet was varied from 30° to -15° to mimic an upward cough as well as a more common downward cough. The schematic representation of the complete study setup has been illustrated in Figure 2 to demonstrate the conditions under which the data were recorded. Finally, to understand the effectiveness of creating a taller partition, the tests were carried out for a reduced jet height of 2 inches above the tabletop and the jet angle fixed at 0° for all three shield configurations.

Results from the study indicated that partitions are effective at blocking some of the speech aerosols, but not all. For the four jet angles, -15°, 0°, 15°, and 30°, the shields with angles of 0° and 45° had similar performance. The partition with shield angle of 90° was expected to perform better when compared to the cases of 0° and 45°. But for the shield angle of 90°, the vortex structures formed were observed to induce higher flow towards the other side of the partition which negated the effectiveness of increased shield angle. When the jet height was lowered (i.e. having a taller partition), all three partitions performed well, therefore suggesting that a taller shield is effective, regardless the shield angle.

Initial conclusions from the study indicate that physical barriers with a shield angle of 0°, which are the most cost effective, perform equally as well as the more complex shields with a 45° and outperform those with a 90° angle.  In areas where personnel may be standing, creating a taller partition is necessary to help ensure proper performance.  Also noted during this study is the importance that the physical barriers create a good seal at the bottom because as mentioned earlier, the typical person will lower their head to cough. As demonstrated in Video 1 with the downward jet plume, if the partition does not create a good seal at the bottom, then the plume can travel underneath the shield and negate its effectiveness. Finally, it is important to note that even with proper partition design, it is prudent to treat them as a secondary safety device with a face covering, such as a face mask, being the primary safety device.