Failure Analysis of a Copper Tube for Pneumatic System

Deoxidized-high-phosphorous (DHP) copper tubes are widely and successfully used in different applications as: water distribution, air-conditioning, solar heating, fuel, oil, and natural gas services and compressed air systems. In the present analysis, a failure of a copper tube composing a pneumatic system of a subway train was investigated by means of on-site examination, metallographic and fracture analyses. Results show that arcs coming from an exposed power cable lead to partial melting of a section of the tube, resulting in loss of pressure and interruption of the train.