Why do ventilation strategies matter in controlling infectious airborne particles? A comprehensive numerical analysis in isolation ward

Huiyi Tan, Keng Yinn Wong, Mohd Hafiz Dzarfan Othman, Hong Yee Kek, Bemgba Bevan Nyakuma, Wai Shin Ho, Haslenda Hashim, Roswanira Abdul Wahab, Desmond Daniel Chin Vui Sheng, Nur Haliza Abdul Wahab, Ardiyansyah Saad Yatim

Research output: Contribution to journalArticlepeer-review

19 Citations (Scopus)

Abstract

A proper ventilation strategy in an isolation ward could promote better indoor air quality for the occupants. This could also reduce the risk of immunocompromised patients contracting healthcare-associated infections (HAI) or airborne diseases such as COVID-19, tuberculosis, and measles among others. This study aims to propose and examine appropriate ventilation strategies in a single-patient isolation ward that can reduce particle settlement in patients. A simplified CFD model of the isolation ward was developed and well-validated against established data. An RNG k-ε model and discrete phase model (DPM) were used to simulate airflow and particle transportation. The study examined the airflow and particle dispersion under a baseline case and four proposed ventilation strategies. Results showed that the baseline case study, which used the ceiling-mounted air curtain was insufficient to prevent the particles from dispersing into the vicinity of the patient. Likewise, the dilution effect under the baseline case and case 4 (wall-mounted air supply diffuser) were relatively weak due to the low air change rate (ACH) of 4/hr and 9/hr respectively. The ventilation strategy in case 4 has a negligible effect on reducing the particles (14%) settling on the patient although the ACH in case 4 was 2-times the baseline case. The present finding ascertains that utilising the combination of ceiling-mounted air diffuser and air curtain jet (case 3) results in zero particle settlement on both patient's and the patient's bed. It also reduced 57% of particles in the vicinity of the medical staff's breathing zone compared to the baseline case.

Original languageEnglish
Article number110048
JournalBuilding and Environment
Volume231
DOIs
Publication statusPublished - 1 Mar 2023

Keywords

  • Healthcare-associated infection
  • Isolation ward
  • Particle dispersion
  • Turbulent airflow
  • Ventilation strategy

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