TYPE-I FITTING OF COPPER TUBES FROM A WATER DISTRIBUTION-SYSTEM

Samples of copper tubes from a cold water distribution system which ha d failed due to pitting whilst in service were subjected to a detailed failure investigation. Analysis of the tubes showed that failure was a result of Type I pitting attack. While the exact cause of pitting wa s unknown, it was hypothesised that it could have been due to changes in the water quality and/or content. The tubes were found to be made f rom phosphorus de-oxidised copper and no anomalies were evident in eit her the chemical composition or the microstructure which could have ca used the pitting observed. It was recommended that the tubes be replac ed and that due attention be given to ensure that the new tubes are fr ee of internal carbonaceous deposits or other foreign matter. (C) 1998 Elsevier Science Ltd. All rights reserved.