A novel approach is proposed to assess a procedure for testing whether a pipeline may be interfered with from DC stray current. With the rise in popularity of portable coupons in AC mitigation testing, the paper proposes a method to evaluate DC stray current with a portable or stationary coupon without requiring potential interruption on foreign structures. This may allow technicians to conduct additional testing on suspected interference spots without requiring the interruption of a foreign pipeline or structure. This paper outlines and proposes a procedure for determining the likelihood of DC stray current interference utilizing coupons. Additionally, the paper recommends and outlines a proposed study to assess the accuracy of the techniques in the proposed procedure. While DC current cannot typically be measured and quantified for a bare metal holiday on a pipeline, coupons allow for a controlled and measurable connection to a simulated pipeline holiday. The procedure may be utilized to distinguish when suppressed potentials are occurring on a pipeline as a result of DC stray current interference rather than from inadequate current provided by CP system, a foreign voltage gradient, shielding or electrical grounding, even when the source of current is unknown. The procedure may also be beneficial in situations with atypical interring-structures where the existence of the interfering structure is unknown or where the applied voltage of the interfering structure cannot be interrupted traditionally such as with the prevalence of DC current situations occurring from installed or newly repaired direct-buried communication utility cables with weak splices at unknown locations. The procedure may also be utilized as an initial step to determine first steps in a DC stray current interference situation.

In August 2022, the United States Department of Transportation Pipeline and Hazardous Materials Safety Administration (PHMSA) revised the Federal Pipeline Safety Regulations to improve the safety of onshore gas transmission lines. PHMSA expects the new requirements will reduce the frequency and consequences of failures and incidents involving onshore natural gas transmission pipelines through earlier detection of threats to pipeline integrity, including those resulting from corrosion or extreme weather events. Additionally, revisions to the regulations address several other areas, including management of change processes, corrosion control, and criteria to repair pipelines. New corrosion control regulations were incorporated into the following sections of the United States Code of Federal Regulations (CFR) Title 49, Part 192, Transportation of Natural and Other Gas by Pipeline: Minimum Federal Safety Standards: 192.319, 192.461, 192.465, 192.473, and 192.478. Additionally, revisions to Sections 192.485 and 192.714 include remedial measures for transmission lines impacted by corrosion.

 

PHMSA’s Regulation Identifier Number (RIN) 2137-AF39 entitled “Pipeline Safety: Safety of Gas Transmission Pipelines: Repair Criteria, Integrity Management Improvements, Cathodic Protection, Management of Change, and Other Related Amendments” (also known as RIN 2 or the Gas Mega Rule) increases pipeline safety regulatory requirements in 49 CFR 192 for operations, maintenance and integrity management.