Airborne CMI Inspection Identifies Crucial Defects in a Buried, Unpiggable Pipeline

Overview:

A client operating a steel sewer line encountered a leak caused by internal corrosion, likely due to the use of ferric chloride. The pipeline, deemed unpiggable and lacking technical documentation, had not been assessed for integrity since its commissioning in 1972. In urgent need of an integrity assessment solution, the client turned to EMPIT's airborne Current Magnetometry Inspection (CMI) to remotely inspect the buried pipeline and assess its overall integrity.

Challenge:

• Inspecting an unpiggable pipeline with no previous integrity assessments
• Addressing internal corrosion and metal degradation caused by ferric chloride usage
• Maintaining pipeline service while ensuring safety and compliance

Solution:

EMPIT's CMI technology overcomes the limitations of traditional ILI tools by remotely evaluating pipeline wall conditions from the earth's surface. With official certification and established technology standards, CMI can detect external and internal pipe wall anomalies, such as general corrosion, SCC, CUI, pipe deformation, and mill features. This non-invasive inspection technique helps operators avoid service disruptions, replacement costs, and ensures compliance with local, national, and international regulations.

Outcome:

The CMI inspection identified areas with significantly higher Probability of Failure (PoF) while no notable increase in PoF was found in other sections. Upon verification through feedback digs, the client discovered crucial internal anomalies with peak depths ranging from 75% to 92% metal loss, and an external dent exceeding 15% of the pipeline's nominal diameter.

Utilizing EMPIT's data, the pipeline operator decided to maintain service and develop an asset management plan to address the identified high-risk sections. This targeted approach saved the client from costly full pipeline replacement and facilitated continued operation in a safe and compliant manner.