Failure stainless steel line


Case Insulated stainless steel (304) pipeline situated on a pipe bridge. An electrical tracing (80°C) is used to prevent coagulation of the product. Leakage occurred after 8 years of service.
 
Cause       
 
Primarily CL-SCC from the outside near location of tracing. At this location the plating of the insulation was defect. Secondly no spacers were used between the tracing and the pipeline, creating higher temperatures locally, asymmetrical stresses.
 
Advice    Recommendations made how to properly apply a tracing and insulation.