2018 Volume 43 Issue 255 Pages 29-36
In designing equipment capacities such as water supply pipe diameter and pump discharge flow rate in the water supply and distribution system, the load calculation method in which the instantaneous maximum flow rate is obtained by using the water supply fixture units ratings as load factors, is generally used. This method was proposed by Roy. B. Hunter in the 1940s in the USA. In Japan, this method was slightly modified according to the circumstances at that time, was described in HASS-206 (current SHASE- S 206) and the design standards for building equipment (Supervised by the Ministry of Land, Infrastructure and Transport). This method has become widespread. However, considering the growing interest in water conservation, this method is not suitable. This is because the water supply load obtained by this method is based on the specifications of sanitary fixtures available at the time when this method was proposed by Hunter, and these values may be deviate from actual conditions. Therefore, in this study, we investigated the water supply characteristics of the latest type of toilet bowl and urinal with advanced water saving features, and calculated their water supply load units. As a result, it was found that the water supply fixture units of the latest type of toilet bowl and urinal equipment are smaller.
