A model to simulate leakage through joints in water distribution systems

The water loss is a phenomenon frequently observed within water distribution systems. A considerable part of water losses occurs either because of the incorrect assembly of joints or because of the fatigue and ageing of the material used to ensure a watertight seal. Moreover, such a leakage is very difficult to detect and to assess. In this work, we present a novel formulation for modelling the pressure effect on the background leakage through the joints. The proposed approach is based on the preliminary evaluation of the enlargement Δω, due to pressure, of the existing space between the outer side of the spigot end of a pipe and the inner wall of the hub end of the adjacent pipe (which is characterised by the area ωatm at atmospheric pressure). Furthermore, the whole procedure is based on the evaluation, by field data or calibration, of a parameter ξ representing the rate of enlarged area ω that, for several reasons, may be not covered by the gasket, ω being the value, at pressure p, of the area above defined.