Numerical simulation of pressure and airflow response of building drainage ventilation systems

Identification of the under-performance of the building drainage and ventilation system as a significant contributor to the transmission of the SARS virus in the ‘Amoy Gardens’ outbreak has prompted a re-examination of the methods adopted to ensure appropriate network design, implementation and maintenance. The physical separation between the miasma present within drainage pipe work and the habitable space occupied by the building user is achieved primarily through the use of the (commonly water-based) appliance trap seal. Systems must therefore be designed such that the integrity of this seal is sustained throughout all user or system-imposed operating conditions. This paper focuses on the work of the authors in defining key simulation model components that facilitate the prediction of the pressure response of building drainage systems and that thus allow an assessment of trap seal integrity to reduce the risk of infection spread. The paper draws upon the empirically defined network characteristics and extensive site data that have, so far, been established independently by researchers in the UK, Japan and Taiwan. The paper identifies the congruency of resultant data, and highlights the potential benefits of pooling research resources such that the contribution of simulation techniques to forensic analysis of virus spread via building drainage systems is confirmed.