Numerical Study of Three Ventilation Strategies in a prefabricated COVID-19 inpatient ward

Abstract

Prefabricated inpatient wards have been proven to be an efficient alternative to quickly extend the caring capacity for patients. In this study, three typical ventilation strategies were studied using computational fluid dynamics in a prefabricated Coronavirus disease 2019 double-patient ward. Pollutants are the respiratory droplets and aerosols injected from two manikins. They are modelled as particles with different diameters (3 μm, 6 μm, 12 μm, 20 μm, 45 μm and 175 μm) by the Eulerian–Lagrangian model. Three ventilation strategies with an identical air change rate of 12.3 h −1 but different layouts of inlets and outlets are implemented. The flow field, flow structures and particle trajectories have been analysed and compared among the three ventilation strategies. The fate of particles is analysed and compared quantitatively. It is found that small particles (<20 μm) can move along with the main flow streams. Most of them are removed by ventilation to the outlet(s). Large particles (>45 μm) cannot move with the flow streams over a long path. Most of them deposit on solid surfaces in different regions of the ward in each ventilation strategy. Health workers should pay close attention to these polluted areas. Targeted cleaning of the polluted areas is necessary in a prefabricated inpatient ward. To promote the removal of some large particles (e.g., 45 μm) by the outlet(s), the outlet(s) should be installed inside the landing area of large particles and close to the polluted source(s).

Insufficient ventilation led to a probable long-range airborne transmission of SARS-CoV-2 on two buses

“…Our study here provides evidence for the probable airborne transmission of SARS-CoV-2 on two buses under a ventilation rate of 3.2 L/s per person or less. The importance of ventilation for SARS-CoV-2 intervention has been recently recognized in at least two major commentaries [ 30 ]; Li et al, 2021; [ [31] , [32] , [33] ].…”

Impact of natural ventilation on exposure to SARS-CoV 2 in indoor/semi-indoor terraces using CO2 concentrations as a proxy

“…That is why, presently, more and more works highlight the importance of achieving adequate indoor air circulations to reduce airborne transmission [ [16] , [17] , [18] ]. Although most of these works are focused on indoor environments with mechanical ventilation [ 19 ], for example, inside hospitals [ [20] , [21] , [22] , [23] ].…”

COVID-19 spread in a classroom equipped with partition – A CFD approach

“…Studies of indoor airflow regimes, room pressurization, and filtration for hospitals and chemical laboratories where infectious disease agents are handled were performed by Barbosa and Brum, 2018 , Liu et al, 2017 to find low-risk conditions. Ren et al (2021) studied numerical simulation of three typical ventilation strategies in a prefabricated Covid-19 inpatient ward in a hospital for a range of droplet diameters. They found that small particles move along with the main flow streams to long distances.…”