Supporting safe operations with ECA

Pipeline safety is a top priority for operators and regulators alike. As part of a continual improvement process, operators are expected to maintain confidence in ongoing reliability by verifying pipeline safety using updated data and validated methods. With the implementation of the Gas Mega Rule, pipeline operators must reconfirm the maximum allowable operating pressure (MAOP) for certain gas transmission pipelines under 49 CFR §192.624. Traditional methods like hydrostatic testing or pipeline replacement can be costly and disruptive. Engineering critical assessment (ECA) emerged as an efficient, data-driven and compliant solution, but industry-wide guidelines for its execution were lacking.

A collaborative approach to ECA methodology development

Dynamic Risk led a consortium of leading pipeline operators representing a significant portion of the gas transmission mileage in the US to develop a robust ECA methodology through collaboration. The approach aligned with the guidelines of 49 CFR §192.632 and applied established data integration and engineering approaches and principles to meet regulatory objectives through a focused and efficient assessment process. ECA vs integrity management objectives

Many of the activities developed to support IM objectives are relevant to ECA objectives. Both ECA and IM processes consider factors such as material properties, operational circumstances, threat assessment and defect assessment, and rely on the same data elements to be integrated for analysis. The difference lies in how the information is used. Integrity management considers a wide range of regulations, industry standards and practices to continually manage the integrity of a pipeline over time. Specifically, 49 CFR §192.632 outlines the requirements for an ECA, namely, to provide the equivalence to a hydrostatic pressure test of the pipe, i.e., to be fit to operate at a test factor appropriate to the class location of the MAOP-R segment. Integrity management is a continual, iterative process, while conversely the ECA is noted to be a one-time event condition snapshot confirming that the pipeline’s design and construction are suitable for operating at the established MAOP. The majority of segments for which the ECA applies (MAOP-R segments) are also subject to 49 CFR §192.710 or Subpart O integrity management and continual evaluation once the ECA has been completed.

How ECA works

To complete an ECA compliant with 49 CFR §192.632, traceable, verifiable and complete (TVC) records for diameter, wall thickness, seam type, and pipe grade are required. Where such values are not available, conservative assumptions can be used for completion of the ECA; however, material properties still must be verified according to 49 CFR §192.607.

The process to determine, acquire and process required data is summarised below:

Phase 1 involves determining feasibility of the ECA, data gathering (existing ILI and other relevant data), records research, data integration and assessment, pre-engineering, and identification of outstanding data needs (data needs may serve to close gaps in TVC material property information and threat assessments).

Phase 2 involves addressing potential mitigations to outstanding data needs by methods such as (but not limited to) additional ILI, additional excavations, and execution of material verification processes. Phase 3 includes the final data integration, engineering analysis, and documentation for the ECA report.

Phases 1 and 2 should be completed at the programme level before beginning work on an ECA to better assess the viability of an ECA and support effective lifecycle planning.

Threats to be considered for ECA

49 CFR §192.632 outlines various threats and conditions that must be assessed to reconfirm a pipeline segment’s MAOP. Since many of these can be addressed using established integrity assessment and integrity management feature analysis methods, it is helpful to organise them within the framework that pipeline operators have relied on for over 25 years as a reference.

Absence of evidence is not evidence of absence. Reliance solely on the historical absence of a threat condition in the assessment path is not sufficient. Segments that require MAOP reconfirmation are evaluated for threat susceptibility using first principles and available data, guided by internal procedures and industry best practices. Threats determined to be non-susceptible within a pipeline segment requiring MAOP reconfirmation, based on sound justification, are considered to require no further assessment.

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Read the article online at: https://www.worldpipelines.com/special-reports/23072025/supporting-safe-operations-with-eca/