A Field Experiment Verification of Theoretical Exponent N1 for FAVAD Method in Defining the Relationship of Pressure and Water Losses

Abstract

The current problem of managing water losses in water supply systems relies on engineering predictions of expected outcomes based on pressure manipulations using hydraulic models or other computational methods. The objective of this experiment was to conduct a field test to validate the theoretical N1 exponent of the fixed and variable area discharges (FAVAD) method. By knowing the pipe material and measuring the pressure and minimum night flow (MNF), the N1 exponent can be defined and compared to recommendations in the literature. Field measurements and experiments were performed in a small settlement in Croatia consisting of 278 house connections and 7.4 km of PVC material pipe network. Pressure manipulation was performed on a pressure-reducing valve (PRV). The resulting value of N1 = 1.76 from the experiment agrees with the literature graphs, which indicate a value of N1 between 1.5 and 2.0. Considering the difference between the studied values and the theoretically calculated MNF of 4%, it can be concluded that the implementation of the presented methodology to determine the N1 exponent can be used in practice. This type of field testing is important because such tests are difficult to perform due to the extensive pressure manipulations during the tests, which can affect the consumers and cause disturbances in the water distribution.