Experimental evaluation of thermal comfort, ventilation performance indices and exposure to airborne contaminant in an airborne infection isolation room equipped with a displacement air distribution system

Abstract

This study is focused in determine the convenience of the use of displacement ventilation strategy in airborne infection isolation rooms (AIIRs). Comfort of the occupants of the chamber, IAQ indices and the exposition of the health worker (HW) to the contaminants emitted by the confined patient (P) are considered in a typical AIIR set up with a hot radiant wall representing an external wall. Three air ventilation rates are tested to determine their influence in the studied variables. Results show that IAQ indices associated with ventilation and general comfort indices for both manikins performs well in the cases studied. Lockup phenomenon associated to displacement ventilation occurs above P but it has a low influence on contaminant exposition of HW because of the influence of the convective boundary layer of HW. The influence of the radiant wall derives part of the fresh air directly to the exhaust and has a low influence the comfort of the manikins.

Experimental assessment of different mixing air ventilation systems on ventilation performance and exposure to exhaled contaminants in hospital rooms

“…These studies highlight the influence of the relative position of the supply diffusers and exhausts on the flow dynamics and hence on the ventilation performance inside the room. An experimental research has been also carried out using a hospital room setup but using DV for a range of ventilation rates from 6 to 12 ACH [37], showing the potential of this ventilation strategy for these spaces if it is well designed, highlighting the high importance of the heat loads in air distribution for this case.…”

“…This study is carried out in an experimental chamber with a typical IHR configuration setup [37] within the HVAC (heating, ventilation and air-conditioning systems) laboratory at the University of Cordoba. The experimental setup can be seen at The nine points that register tracer gas concentration around the inhalation point of HW are distributed in three columns (1, 2 and 3) and three rows (H, M and L) in the same vertical plane.…”

“…Inside the experimental chamber there are two thermal manikins representing a patient, CP, and a health worker, HW. Both manikins have the same geometry, and have been used previously in other research studies [6,37,42]. The body of the manikins is heated to achieve a homogeneous surface temperature of 34 ºC which lead to the thermal gains summarized in Table 2.…”

Displacement ventilation with radiant panel for hospital wards: Measurement and prediction of the temperature and contaminant concentration profiles

“…The exhaled jet from the source manikin penetrated a long distance along the exhaled direction. On the other hand, there are also other studies https://doi.org/10.1016/j.buildenv.2019.106197 Received 30 March 2019; Received in revised form 7 June 2019; Accepted 7 June 2019 which have indicated that DV is an effective ventilation system for air infection wards [6][7][8]. Li et al [6] examined the exposure risk for the co-occupant under displacement, mixing and underfloor ventilation by the numerical study.…”

“…As a result, it was found that DV could provide better air quality when the droplet residuals are smaller than 5 μm and the co-occupant is located a certain distance from the source. Berlanga [7] et al demonstrated that the exhaled contaminant could go up with the plume of the source manikin successfully when the manikin that exhaled contaminant air was facing up. The suitability of DV for avoiding nosocomial infection is still controversial [9], what is clear is that DV is superior to other ventilation systems when the contaminant is emitted with positive buoyancy force or is combined to the thermal plume of a heat source.…”