Operators are faced with a growing market demand for the gas they transport from the wellhead to the burner tip. Increasing throughput is essential to meeting these growing needs. However, achieving those higher pressures to accomplish the greater throughput also increases the risk to operating the pipeline systems. And increased risk means greater need for comprehensive and mature Integrity Management Programs. To help pipeline operators navigate balance between market opportunities and operational safety, PHMSA issued in 2008 a set of rules and guidelines, the “Standards for Increasing the Maximum Allowable Operating Pressure for Gas Transmission Pipelines” commonly known as the Alternative MAOP Rule. In this article, we'll take a closer look at the guidelines and requirements set forth by the Alternative MAOP Rule and how pipeline operators can use it to increase both the safety and efficiency of their operations.
What did Change Under the Alternative MAOP Rule?
The Standards for Increasing the Maximum Allowable Operating Pressure for Gas Transmission Pipelines or Alternative MAOP Rule, amended the existing pipeline regulations in fact updating the current regulatory standards to reflect the improvements in pipeline materials, assessment tools, and maintenance practices, which have reduced the risk of failure in pipeline fabricated from steel pipe.
The rule allows use of an established industry standard for the calculation of MAOP, but limits the application of the standard to pipelines posing a low safety risk based on location and limiting the type of acceptable materials and fabrication methods used to manufacture the pipe.
Prior to the implementation of the Alternative MAOP Rule, PHMSA used to grant special permits on a case-by-case basis to allow operation of particular pipeline segments at a higher MAOP than was currently allowed. These special permits were limited to pipelines operating in Class 1, 2, and 3 locations and were conditioned on demonstrating the pipeline's design and construction and the operator's performance. PHMSA codified the conditions and limitations of the special permits into standards and listed in articles:
- 49 CFR 192.112 –Additional design requirements for steel pipe using alternative maximum allowable operating pressure.
- 49 CFR 192.328 - Additional construction requirements for steel pipe using alternative maximum allowable operating pressure. and
- 49 CFR 192.620 - Alternative maximum allowable operating pressure for certain steel pipelines.
Currently, under the guidelines set forth by the Alternative MAOP Rule, Pipelines in Class 1 locations may be operated at 80% of SMYS, and pipelines in Class 2 and Class 3 locations may be operated at 67% SYMS and 56% SYMS, respectively. The Alternative MAOP Rule does not affect pipelines in densely populated Class 4 locations, which still must be kept under 40% SYMS.
What pipelines qualify for the alternative MAOP rule?
Keeping public safety as the main objective, PHMSA set more rigorous safety standards. A rule of general applicability, level the field and set clear conditions for approval eliminating the need to craft the conditions based on individual evaluation. An operator seeking to operate at a higher percentage of SMYS would have to certify that a pipeline is built according the design requirements of 49 CFR § 192.105, change in class location (49 CFR § 192.611), and maximum allowable operating pressure (49 CFR § 192.619).
As with the special permits, this rule allows an operator to qualify both new and existing segments of pipeline for operation at the higher MAOP, providing the operator meets the conditions for the segment..
192.620(b) indicates when an operator may use the alternative MAOP regulation:
- The pipeline segment is in a Class 1, 2, or 3 location;
- The pipeline segment is constructed of steel pipe meeting the additional design requirements in § 192.112;
- The pipeline segment is under a control and data acquisition system provides remote monitoring and control of the pipeline segment(SCADA);
- The pipeline segment meets the additional construction requirements described in § 192.328;
- The pipeline segment does not contain any mechanical couplings used in place of girth welds;
- If a pipeline segment has been previously operated, the segment has not experienced any failure during normal operations indicative of a systemic fault in material as determined by a root cause analysis, including metallurgical examination of the failed pipe.
- At least 95 percent of girth welds on a segment that was constructed prior to December 22, 2008, must have been non-destructively examined in accordance with § 192.243(b) and (c).
Still, several pipelines segments will not qualify under Alternative MAOP Rule including the following:
- Segments in Class 4 locations. In addition to the increased consequences of failure in a Class 4 location, the level of activity in such a location increases the risk of excavation damage.
- Segments of grandfathered pipeline already operating at a higher stress level but not constructed in accordance with modern standards.
- Segments with bare pipe or segments that lacks the coating needed to prevent corrosion and to make cathodic protection effective.
- Pipe with wrinkle bends. Section 192.315(a) currently prohibits wrinkle bends in pipeline operating at hoop stress exceeding 30 percent of SMYS.
- Pipe experiencing repeated failures would require a rigorous root cause assessment to ensure is not systemic problem (such as seam flaws). Such pipe is more likely to have inherent defects that can grow to failure more rapidly at higher stress pressures.
- Pipe manufactured by certain processes (usually prior 1960), such as low frequency Electrical Resistance Welding processes (ERW), will not qualify because it could not satisfy the requirements of the rule.
HOW TO MAINTAIN PIPELINE INTEGRITY UNDER HIGHER PRESSURES?
Operators need to remain vigilant and observant to ensure the integrity of the pipeline is not being compromised. To develop compliance solutions for these risks, regulatory consulting will help you analyze each situation, identify the critical path, and mobilize appropriate resources to deliver cost effective solutions in a timely manner. An Integrity Management Program (IMP) consistent with CFR 192, Subpart O (for gas operators) will describe the process for implementing each program element, how relevant decisions will be made and by whom, a time line for completing the work to implement the program element, and how information gained from experience will be continuously incorporated into the program. An operator must make continual improvements, or mature the program.
How G2 Integrated Solutions Can Help
After analyzing your pipeline with a specialized integrity program, G2 Integrated Solutions will be able to tell you whether or not your pipeline is eligible for the Alternative MAOP Rule. If problems are found that would prevent your pipeline from being eligible, our risk management experts will provide you with the corrective measures that will be necessary to get your pipeline up to spec.
Take the first step to operating your pipeline safely and efficiently, contact us today.