The Pipeline and Hazardous Materials Safety Administration (PHMSA) issued its final rule amending the pipeline safety regulations to prescribe safety requirements for the operation of certain gas transmission pipelines (49 CFR 192) at pressures based on higher operating stress levels. The result is an increase of maximum allowable operating pressure (MAOP) over that currently allowed in the regulations. This final rule updates regulatory standards to reflect improvements in pipeline materials, assessment tools, and maintenance practices, which together have significantly reduced the risk of failure in steel pipeline fabricated and installed over the last twenty-five years. The final rule would apply to both new and existing pipelines, and would allow use of an established industry standard for the calculation of MAOP, but limit application of the standard to pipelines posing a low safety risk based on location, materials, and construction.

PHMSA has previously granted special permits on a case-by-case basis to allow operation of particular pipeline segments at a higher MAOP than currently allowed under the design requirements. With the publication of this final rule, this case-by-case approach to approving operation under a special permit at higher operating stress levels is no longer needed, and PHMSA will terminate its review of any pending applications. Under the final rule, several types of segments will not qualify for the higher MAOP:

• Segments in densely populated Class 4 locations
• Segments of grandfathered pipeline already operating at a higher stress level but not constructed in accordance with modern standards.
• Bare pipe.
• Non-steel pipe
• Pipe with wrinkle bends
• Pipe experiencing failures indicative of a systemic problem, such as seam flaws, during the initial hydrostatic testing.
• Pipe manufactured by certain processes, such as low frequency electric welding process.
• Segments which cannot accommodate internal inspection devices.

The rulemaking imposes new and additional design, construction, and operation standards to pipe operating at the higher MAOP, including:

• Incorporating by reference ASTM Designation: A578/A578M-96 (Reapproved 2001) “Standard Specification for Straight-Beam Ultrasonic Examination of Plain and Clad Steel Plates for Special Applications”.
• Prescribing additional design requirements in §192.112.
• Prescribing additional construction requirements, including rigorous quality control and inspections, in §192.328.
• Specifying additional operations, maintenance, testing, and notification requirements.

PHMSA made some revisions to the final rule from the provisions proposed in the NPRM on March 12, 2008. Some of the revisions include:

• Use of an alternate International Institute of Welding Carbon Equivalent (CE) formula.
• Allow a long-term coating integrity monitoring program to be used as a basis for allowing pipe temperatures in excess of 120 degrees Fahrenheit. Operators must submit their programs to the PHMSA pipeline safety regional office for review before pipeline segments may be operated at alternative MAOP at these higher temperatures.
• Allow a root cause analysis of any failures as a way of justifying qualification of a pipeline segment.
• Revised the required patrol frequency from 26 patrols per year, to once per month, at intervals not to exceed 45 days.

Effective date of the final rule is November 17, 2008. For a copy of PHMSA’s Final Rule on Increasing MAOP for Gas Transmission Pipelines, contact Jessica Roger.