Hydraulic and Technological Investigations of a Phenomenon Responsible for Increase of Major Head Losses in Exploited Cast-Iron Water Supply Pipes

The paper presents results of investigations of influence of major head losses on exploitation properties of water supply pipes after 30-year exploitation. The tested materials were cast-iron pipes with the internal diameter of 150 mm. A flowability drop coefficient ηt with average value of 0.45 was determined. Using the measured values of pressure difference Δp determined the absolute roughness of internal walls of the pipes after 30-year...