This study shows an experimental method to investigate the drainage capacity of drain from washing machines in the drainage system of apartment houses, and verifies its effectiveness. In this experiment, drain from washing machines using a detergent sold in the market and clear water drain are applied to a single stack system installed to a high rise tower with 10 stories above the ground (approximately 30m high) respectively. Taking the pressure and airflow fluctuation thus obtained as an index, the characteristics of both drain are introduced, and a possible risk to be given to the drainage system of drain from washing machines in verified. For a reference in judging the result of the experiment on drain from washing machines, the relationship between the detergent foam height and the pressure inside the pipe is explained.
