Downward flow ventilation systems are one of the most recommended ventilation strategies when contaminants in rooms must be removed and people must be protected from the risk of airborne cross-infection. This study is based on experimental tests carried out in a room with downward flow ventilation. Two breathing thermal manikins are placed in a room face to face. One manikin’s breathing is considered to be the contaminated source to simulate a risky situation with airborne cross-infection. The position of the manikins in relation to the diffuser and the location of diffuser in the room as well as the distance between the manikins are being changed to observe the influence of these factors on the personal exposure of the target manikin. The results show that the DWF in different situations often is unable to penetrate the microenvironment generated by the manikins. The downward ventilation system can give an unexpected high level of contaminant exposure of the target manikin, when the distance between the manikins is reduced.
Indoor Air Online, 2013, Vol 23, Issue 1, p. 62-73