Scope
Schedule
2019-2020
Location
Minnesota
Estimated Cost
$500k
Client
Midstream Distribution and Transmission Company
Project Overview
The client was responsible for a 44‑mile pipeline corridor that traveled through a dense urban environment, intersecting multiple High Consequence Areas (HCAs) and running parallel to 37 high‑voltage overhead powerline circuits. This complex setting exposed the system to elevated corrosion risks, AC interference, and increased operational and regulatory pressure. The client needed a strategic, data‑driven integrity management approach to protect critical assets, reduce external metal loss, and ensure continued compliance with federal safety standards. To meet these needs, LSC provided comprehensive integrity management support, combining in‑line inspection (ILI), direct examination, AC modeling, and systemwide mitigation design to strengthen the pipeline’s long‑term performance.
Deliverables:
- In-Line Inspection
- AC Mitigation Design
- AC Mitigation Installation
- AC Mitigation Design Validation
- Indirect Inspections
Project Team
Nick Anderson
Director, Commercial Strategy
Steve Spooner
Project Manager
Tom Harloff
Cathodic Protection Technician
Comprehensive Integrity Assessments
LSC began by completing an ILI feasibility assessment, selecting the appropriate inspection tools, and supporting the execution of a baseline ILI on the 16‑inch natural gas pipeline. The inspection identified significant external metal loss, triggering targeted excavations to validate tool data, perform repairs, and gather evidence for root‑cause analysis.
LSC’s Direct Examination Technicians documented the pipeline’s physical condition and surrounding environmental factors, while indirect inspections and installation of AC/DC monitoring coupons provided deeper insight into corrosion behavior. These assessments confirmed that AC interference—driven by proximity to high‑voltage transmission structures—was the primary cause of the external metal loss.
Engineered Mitigation & System Enhancement
LSC then completed advanced AC modeling and delivered a targeted mitigation design addressing the identified interference risks. The upgraded AC mitigation system was installed, commissioned, and validated, despite complexities created by multiple collocated pipelines of different ages, coating systems, and electrical continuity conditions.
As dozens of new DC decoupling devices were integrated, LSC continued to monitor system performance and began modeling increased circuit capacitance to determine which devices required replacement with next‑generation designs. This engineered approach reduced long‑term corrosion exposure, strengthened cathodic protection system performance, and significantly improved overall asset reliability for the client.
