Failure analysis of water supply system in the Polish city of Głogów

• The failure rates of water supply system in winter and summer time were calculated.
• Failure rates differed due to such materials as steel, grey cast iron and plastics.
• Failure rates differed due to kind of the pipe (distribution or house connection).

The aim of this work is to diagnose the operation (and faults) of the water supply system in Głogów, Poland. The failure analysis has been conducted basing on the operating data from 2007–2010.About 140 km of main and distribution conduits with diameters of 80–700 mm and 42 km of house connections with diameters of 25–200 mm have been investigated. The pipes are mainly made of grey cast iron, steel, and plastic. The analysis of the number of failures and failure rate λ in each year and on average in the whole inspected period involves a division into types of water-pipe networks as well as into the materials and diameters of particular conduits.On average, in 2007–2010, the values of indicator λ (fail./(km a)) were equal to 0.18 for mains, 0.31 for distribution pipes, and 0.49 for house connections. Failure rates of main and distribution conduits made of steel, grey cast iron and plastics were equal to 0.68, 0.25 and 0.08, respectively. The failure rate was almost two times higher for water mains and distribution conduits in winter (0.41) than in the rest of the year (0.23). As the literature and own investigations indicate, the technical condition of water network in Poland is improving, also in Głogów. Nevertheless, failure rate is higher than in other European countries. In Poland, the old grey cast iron and steel conduits are being modernized, which entails the increase of water-pipe reliability, the decrease of water losses, and the improvement of water quality.