Air Flow Door Barrier for Airborne Infection Isolation Rooms

Bård Venås,Trond Thorgeir Harsem,Anders Welde Vikan,Merethe Cecilie Lind,S.I Tanabe,G Cao,M.C Gameiro Da Silva,I Nastase,L Mazzarela,J Kurnitski,H Zhang,C Inard,P Wargocki

doi:10.1051/e3sconf/201911102063

Abstract

Airborne Infection Isolation Rooms (AIIRs) are used in hospitals to counter the spread of airborne infections. These rooms usually work well as long as the doors to the patient rooms are closed. However, passage through open doorways initiates air flows that may lead to containment failure. This paper presents a new “Air Flow Door Barrier” system for AIIRs and analyses its efficiency through CFD simulations. The overset mesh method is used to represent a hinged door and a person transiting from the patient room to the anteroom. The new system consists of a fan which introduces filtered patient room air into the anteroom through large displacement diffusors. It runs in synchronization with the door operator and produces an evenly distributed velocity across the open doorway. It is found that the system has the potential to remove nearly all transfer of air out from the patient room. The development of the system is part of an ongoing project aimed at finding cost-effective solutions for retrofitting existing patient rooms. However, the system also has the potential to be beneficial when considering inclusion in new standard AIIRs.

Highlights

Airborne infection isolation rooms (AIIRs) are used in hospitals to counter the spread of airborne infections
The picture below shows that the intrusion of patient room air into the anteroom seems all but completely supressed by an air flow barrier rate of just 300 L/s (Figure 7b)
This paper presents and investigates an idea for a system reducing the risk for contamination failure caused by door and person induced air flows

Summary

Introduction

Airborne infection isolation rooms (AIIRs) are used in hospitals to counter the spread of airborne infections. These rooms are built with tight room envelopes and are equipped with ventilation systems keeping them at lower air pressure than the surrounding parts of the building. The under-pressure ensures that flow through remaining openings is directed into the patient room, inhibiting possibly contaminated air from escaping the patient room. If properly built such systems work well as long as the door to the AIIR is closed. Previous studies have shown that door opening, and passage, are significant causes for containment failure in hospitals [1, 2]

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