Factors Influencing Stress Corrosion Cracking of Gas Transmission Pipelines: Detailed Studies Following a Pipeline Failure: Part 2 — Pipe Metallurgy and Mechanical Testing

Following a failure caused by stress corrosion cracking (SCC) on an NPS 8 pipeline in the Nova Gas Transmission (NGTL) system, a detailed investigation was undertaken to understand the contributing factors resulting in the failure. Studies included site characterization using the NOVAProbe, followed by a detailed excavation, sampling, pipe replacement and subsequent metallurgical analysis. In total, 1.1 km of pipe was inspected and replaced. This paper will detail the results of pipe inspection, mechanical testing and metallurgical analysis following excavation. Possible correlation of the results with potential SCC severity is discussed.