ABSTRACT

Two physical models, namely the washroom unit and the plumbing unit, were constructed with reference to local standard and local practice. Figure 2 shows the overall layout of washroom unit. Sanitary fitments, including water closet, wash basin, bathtub and shower tray are each connected to one drain pipe. Drain pipes of water closet and wash basin are joined to a main waste pipe whereas drain pipes of bathtub and shower tray lead to another main waste pipe. Circular preformed openings are installed on the raised floor of the washroom unit. These openings allow the insertion of 150 mm diameter concrete discs/cylinders with different coefficient of permeability for different rates of water seepage (Wong et al., 2016).