An empirical approach to determine peak air pressure within the 2‐pipe vertical drainage stack

Abstract

Following the massive outbreak of SARS (Severe Acute Respiratory Syndrome) in early 2003, the drainage systems in high‐rise residential buildings have become a major concern. Inappropriate drainage system design may cause pressure fluctuations and depletion of the water trap seal. In Taiwan, most vertical drainage stack pipes serving medium‐height apartment blocks are designed as 2 or more vertical pipe systems. A prediction method to determine the air pressure distribution within the single‐stack vertical drainage system with a single discharge has already been established. This paper expands this prediction method to allow the air pressure distribution of the 2‐pipe vertical drainage and vent system, which is widely used in Taiwan, to be predicted. Comparisons between the measured data and calculated values reveal that the prediction method can reproduce the negative and positive peak air pressure values within the 2‐pipe vertical drainage stack given single point discharge and steady flow conditions. A prediction model based on empirical parameters offers a reference for drainage system designers designing and maintaining water trap functions in buildings. This prediction method can be easily applied to drainage system design.