Evaluation of Simultaneous Demands for Water Supply for Domestic Washroom Appliances

This study examines the probable maximum simultaneous demands of water supply facilities at an acceptable level of reliability for some high-rise residential buildings in crowded cities. In particular, the probable maximum simultaneous water demands of domestic washrooms are derived for some usage patterns that the appliances in the same washroom would not operate simultaneously. The model parameters including usage patterns and operating flow rates of some domestic appliances were surveyed from 597 domestic washrooms of 14 typical high-rise residential buildings in Hong Kong. The results revealed that, with the surveyed data and original design data as references, the probable maximum simultaneous demands were only about 50% of those estimated for assuming all appliances in simultaneous operation. The results would be useful in updating the calculation of water supply plants and piping systems for high-rise residential buildings at a balance of cost and system reliability. This study also demonstrated a template of database development for estimating the probable maximum simultaneous demands for water plants and piping systems of residential buildings in crowded cities.