Abstract
This study discusses the drainage performance evaluation and the design method of horizontal drainage pipe systems with drainage header piping, which are applied to SI housing units. The drainage performance evaluation was also discussed in the previous papers by focusing mainly on drainage systems comprising horizontal drainage pipes between the drainage stack and the sanitary fixture with lengths exceeding 7m ('total piping length' hereafter). For domestic waste drainage systems, the piping length between the drainage header, a confluent point of drainage flows, and the sanitary fixture ('drainage header piping length' hereafter) exceeded 5m. In reality, however, there are many drainage systems that are configured with total piping lengths and drainage header piping lengths that are shorter than those used for our studies. It is suspected that shorter piping lengths relate to the performance of the combined drainage inducing siphon and the rate of backflow, which have a significant influence on the overall drainage performance. Based on the assumption that a horizontal drainage pipe system employs the total piping length and the drainage header piping length that are both short, this paper conducts a combined drainage experiment and discusses the evaluation methods of the system's drainage performance. Merits of having such a drainage system in SI housing units are also examined based on the results of the experiment.
