Investigation on the contaminant distribution with improved ventilation system in hospital isolation rooms: Effect of supply and exhaust air diffuser configurations

Abstract

Expected risk of infection from patients to healthcare workers in an AIIR was found.• We investigated how to remove airborne contamination effectively in AIIRs.• Both full-scale field experiments and CFD simulations were performed. • Transport of gaseous pollutants is indicated by tracer gas.• By changing the exhaust air flow, the exposure pollutant level was significantly reduced. A B S T R A C TThis study, that is practice-based learning in a real hospital construction project, has evaluated the ventilation performance of three strategies in the protection of health care workers and HVAC control for airborne infectious diseases induced by contaminated exhaled air from patients in a negative pressure isolation room. This paper examines air flow path and airborne pollutant distribution by computational fluid dynamics modeling and field measurement. In hospitals, the risk of virus diffusion mainly depends on air flow behavior and changes in direction caused by supply air and exhaust air locations. An improved isolation room ventilation strategy has been suggested, and is found to be the most efficient in removing contaminants based on the observations and simulation results from three ventilation systems. The results show that ventilation systems utilizing the "lowlevel extraction" technique are very effective at removing pollutants in the human breathing zone. A new clean isolation room ventilation strategy has been developed that employs two exhaust air grilles on the wall behind the bed at low floor level, coupled with a fan filter unit, and is found to have the highest pollutant removal efficiency.

Modelling aerosol transport and virus exposure with numerical simulations in relation to SARS-CoV-2 transmission by inhalation indoors

“…In earlier studies, pathogen transmission has been investigated widely in various indoor environments ( Li et al, 2007 , Morawska et al, 2017 , Ai and Melikov, 2018 ). In many cases, CFD and experimental studies have been conducted to examine the airborne transmission in simplified environments ( Yu et al, 2004 , Zhang and Chen, 2006 , Liu et al, 2017 ) that may have an association with ventilation ( Li et al, 2005 , Olmedo et al, 2012 , Cao et al, 2015 ), airflow interaction ( Bivolarova et al, 2017 , Li et al, 2018a , Ai et al, 2019 ), in hospitals ( Yu et al, 2005 , King et al, 2015 , Cho, 2019 ) and offices ( He et al, 2011 ). Certain studies also consider transport induced by human motion ( Edge et al, 2005 , Han et al, 2014 ) as well as breathing, talking and coughing ( Gupta et al, 2010 , Licina et al, 2015 , Li et al, 2018b ).…”

What surgeons should know about emergency operation for COVID-19 confirmed patients: A case report

“…We believe that a negative-pressure OR addresses many of these concerns [ 10 ]. The negative pressure inside the OR was maintained at a negative pressure of 4.7 Pa or greater, and the air introduced from the perforated supply diffuser from the ceiling was discharged through an exhaust grill located at a height of 110 cm from the floor at all four corners of the OR [ 11 ] ( Fig. 2 ).…”

Reducing Morbidity and Mortality Rates from COVID-19, Influenza and Pneumococcal Illness in Nursing Homes and Long-Term Care Facilities by Vaccination and Comprehensive Infection Control Interventions

“…Four modelling studies demonstrated how to minimise the contamination of airflows in respiratory disease isolation rooms. One found that directing fresh airflows from the ceiling over the patient's bed and exhausting airflows through the wall behind the bed caused the least contamination of a manikin representing an HCW standing in front of the patient to provide care [82]. A study of contamination from door opening as a manikin representing an HCW entered from an anteroom found sliding doors reduced contamination compared to opening doors [83].…”