Section 192.624(c)(6) defines Method 6 as “an alternative technical evaluation process that provides a documented engineering analysis for establishing MAOP.”

This definition is intentionally broad, providing a framework rather than a prescriptive procedure. When an operator chooses to utilize Method 6, it must notify PHMSA at least 90 days in advance of its use, in accordance with Section 192.18. This notification is the core of the Method 6 process and must provide a comprehensive engineering justification. The specific details outlined in Section 192.624(c)(6) include:

• A detailed description of the alternative technical evaluation process to be used.
• The engineering analyses and supporting calculations used to determine the reconfirmed MAOP.
• All data sources and assumptions that form the basis of the analyses.
• A description of how the chosen approach confirms the integrity of the pipeline at the proposed MAOP and provides a level of safety equivalent to the other reconfirmation methods.

The terminology used by PHMSA, specifically “alternative technology,” has inadvertently created a significant point of confusion. Many operators interpret this phrase to require the development or validation of new tools, novel inspection technologies or unproven experimental equipment. This perception has led to a widespread assumption that Method 6 carries an immense regulatory burden, equivalent to introducing an entirely new integrity assessment method for industrywide approval. Consequently, many operators have shied away from Method 6, defaulting to the operational and financial certainties of pressure testing or replacement, even when those options are disproportionately expensive or disruptive for the specific issue at hand.

A critical point often overlooked is that Method 6 is not about inventing new or experimental technology. In practice, Method 6 should be viewed as a structured regulatory pathway that allows an operator to make a formal engineering case for a pipeline segment’s fitness for service. The “alternative” aspect of Method 6 is not the physics or the engineering principles; it is the application of engineering judgment to existing data, industry-accepted analytical techniques, and a thorough understanding of a pipeline’s history.

PHMSA’s intent with Method 6 is to provide operators with flexibility in situations where traditional methods are impractical, unnecessary or create disproportionate operational risk. The core requirement is that the operator must demonstrate through rigorous analysis and documentation that its alternative approach provides a level of safety equivalent to a hydrostatic pressure test.

In other words, Method 6 is an opportunity to “make your case” using sound, defensible technical analysis, rather than a mandate to demonstrate a new technology. The burden of proof is on the operator to present a clear, conservative and comprehensive justification.

A successful Method 6 submittal is built on a foundation of discipline and documentation. It relies on compiling known information into a coherent technical narrative. This can be broken down into three areas:

1. Make Your Case With Engineering, Not Assumptions

Successful Method 6 applications depend on a complete and well-documented technical file. This begins with clearly defining the pipeline segments in question and gathering all available information, which may include:

• Construction records, alignment sheets and as-built drawings.
• Material property records, even if not fully TVC (e.g., steel grade, seam type).
• In-line inspection (ILI) data, including reports for corrosion, dents or cracking.
• Historical operating data from SCADA systems, showing pressure fluctuations and maximums over time.
• Historical survey records and data related to corrosion and monitoring, demonstrating continual surveillance and O&M execution.
• Records of leaks and repairs, including causes of the leaks and types of repairs, such as the installation of Type A or Type B sleeves.

Where data gaps inevitably exist, the operator must make conservative, documented assumptions. For example, if the specific yield strength of a 1960s-era pipe is unknown, the analysis should assume the lowest specified minimum yield strength (SMYS) for pipe manufactured during that period. This conservative approach demonstrates a commitment to safety and strengthens the overall engineering argument.

2. Practical Example Applications

The true value of Method 6 is most evident in specific, common industry scenarios where other methods are inefficient:

• Short pipeline segments: Consider a 10-mile pipeline with fully TVC records except for a 100-foot segment installed to accommodate a new road crossing in the 1970s. The pressure test and material records for this short replaced pipe segment are incomplete. Under Section 192.624(a), this relatively small section would trigger MAOP reconfirmation. A pressure test or replacement would be extremely costly and disruptive for such a small anomaly. Using Method 6, an operator could combine ILI data showing no defects, a long history of safe operation, and conservative material property assumptions for the 100-foot piece into an engineering analysis that justifies the existing MAOP. Additionally, if the operator does not want to utilize conservative assumptions, material properties could be verified through a material verification program.
• Incomplete pressure test records: In many cases, legacy records are administratively incomplete rather than technically deficient. A pressure test chart might be missing a required signature, the calibration record for the pressure gauge may be lost or the chart itself might be illegible, but other project documentation confirms the test was successfully performed at a specific pressure. Instead of retesting a pipeline that has operated safely for decades, Method 6 allows an operator to assemble the available evidence — such as verified material properties, a stable operational history and corroborating documents — into a defensible evaluation that confirms the pipeline’s integrity without subjecting it to another high-pressure test.

3. Operational and Cost Benefits

One of the compelling advantages of Method 6 is the significant reduction in both cost and operational risk. By eliminating unnecessary fieldwork, operators can realize substantial benefits:

• Cost reduction: Method 6 eliminates the direct and indirect costs associated with conventional methods, including expenditures on excavation, dewatering, gas blowdowns, welding and site restoration. It avoids the capital outlay for temporary test headers, bypasses or full-scale pipe replacement.
• Risk mitigation: It reduces the inherent safety risks associated with construction and high-pressure testing, such as accidental excavation damage or, in rare cases, a test failure on a legacy pipe. Furthermore, it prevents extended service outages and the associated customer and commercial impacts.
• Resource optimization: By using an analytical approach for low-risk segments, operators can focus their valuable field resources, integrity engineers and capital budgets on higher-risk areas of their systems that present a greater threat to public safety and the environment.

When properly applied, Method 6 allows an operator to reduce both capital and operations and maintenance (O&M) expenditures, minimize system downtime, and maintain safety while avoiding unnecessary stress on legacy infrastructure.

Method 6, Alternative Technology, is neither a regulatory “last resort” nor a high-risk gamble. When approached thoughtfully and methodically, it is a powerful, flexible tool that empowers operators to apply sound engineering judgment, established safety principles and deep operational insight to complex MAOP reconfirmation challenges under the Mega Rule.

The keys to success are discipline and documentation: Know your pipeline, be conservative where uncertainty exists, and clearly demonstrate how your analysis provides a level of safety equivalent to other reconfirmation methods. When done well, Method 6 can achieve the same regulatory objective — a safe, justified MAOP — as a pressure test, with far fewer disruptions and greater operational efficiency, ultimately benefiting both the operator and the public.