Industrial experience and research into the causes of SARS virus transmission in a high-rise residential housing estate in Hong Kong

The Severe Acute Respiratory Syndrome (SARS) outbreak in 2003 triggered concerns regarding the ability of buildings to resist disease transmission. In particular, the outbreak that occurred in the high-rise residential blocks in the Amoy Gardens housing estate, sounded an alarm to the local practice of design, installation, commissioning, operation and maintenance of building services systems. Virus transmission through the vertical drainage stack is believed to have been one of the causes of disease transmission in Amoy Gardens. In this paper, the authors share their experiences and research findings on the building drainage system. The paper includes a review of the outbreak incident in Amoy Gardens; and of the observations and site measurements of foul air and water back flow in the drainage system of another vacant high-rise residential housing estate. In addition, tracer gas measurements were studied in order to verify the upwards flow of air in the vertical stack. These field studies allow comparisons between the gas flow from the drainage system to the living accommodation, and confirm the hypothesized infection route. Finally, the authors make recommendations on the proper design and operation of high-rise building drainage systems. Practical application: Sanitary drainage systems form a critical engineering component in maintaining hygienic conditions in buildings. In fact the issue has been addressed over several hundreds of years, for example during the Black Death outbreak worldwide. Despite this, the SARS outbreak demonstrates that there is still room for improvement on the safety of soil waste disposal in buildings. The findings in this paper shed light on the understanding of the outbreak in Hong Kong, and on the critical aspects to avoid performance failure in soil waste disposal.