Pipeline Safety: Grant of Waiver; Alyeska Pipeline Service Company

AGENCY:

Research and Special Programs Administration (RSPA), DOT.

ACTION:

Notice; grant of waiver.

SUMMARY:

The Research and Special Programs Administration's (RSPA) Office of Pipeline Safety (OPS) is granting Alyeska Pipeline Service Company's (Alyeska) petition for a waiver of the pipeline safety regulation that requires an operator to reduce the pressure of a pipeline to not more than 50 percent of the maximum operating pressure whenever the line pipe is moved.

SUPPLEMENTARY INFORMATION:

Background

Alyeska petitioned RSPA/OPS for a waiver from compliance with the requirements of 49 CFR 195.424(a) for 420 miles of aboveground line pipe in the Trans Alaska Pipeline System (TAPS). TAPS was designed and constructed between 1973 and 1977 to transport oil 800 miles from Prudhoe Bay, Alaska, to Alyeska's marine terminal at Valdez, Alaska. Over half of the TAPS pipeline was constructed aboveground. Section 195.424(a) does not allow a pipeline operator to move any line pipe unless the pressure in the pipeline section is reduced to not more than 50 percent of the maximum operating pressure (MOP). Alyeska argues that lowering the pressure on the aboveground portion of TAPS is not necessary and is disruptive and burdensome to its pipeline operations.

The requested waiver would apply whenever routine maintenance necessitates that the aboveground line pipe be moved laterally, longitudinally or vertically, to relieve pipe stresses and restore the pipe to its intended position. On July 22, 2004, RSPA/OPS published a notice in the Federal Register requesting public comment on Alyeska's waiver request (69 FR 43880). No comments were received in response to this Notice.

Findings and Grant of Waiver

RSPA/OPS finds that Alyeska's requested waiver from § 195.424 (a) is not inconsistent with pipeline safety for the following reasons:

1. Because of its unique design, the aboveground portion of TAPS behaves differently from conventionally buried pipelines. Moving a buried pipeline during maintenance activities may impose additional stresses on the pipe. Thus, lowering the pipeline pressure prior to movement provides a safety factor and reduces the possibility of pipeline failure from overstressing the pipe. In contrast, TAPS’ aboveground pipeline is placed on support structures that allow the pipeline to move freely within a design range without imposing additional stresses on the pipeline. This design feature eliminates or reduces stresses imposed on the pipeline due to thermal expansion, seismic events, or settlement of the support structures and reduces the need to reduce pressure on the pipeline.

2. The TAPS pipeline is fully restrained where it transitions between underground and aboveground sections. The point of restraint is located approximately 1,000-1,500 feet away from the transition. This is point where the pipeline begins to behave as a fully restrained underground structure. Aboveground piping is more easily monitored and is much less restrained than underground pipe. Stresses imposed on aboveground pipe in the TAPS system are resolved by allowing movement of the pipe on support structures. Therefore, it is not necessary to reduce operating pressure on aboveground sections of the TAPS pipeline during routine maintenance activities.

3. Alyeska has established maintenance procedures to ensure the safety of the aboveground portion of this pipeline. These maintenance procedures ensure that the pipeline is maintained within its safe operating design limits. Alyeska has procedures to:

• Install temporary support brackets to lift and replace the pipeline's vertical support members (VSMs);
• Calibrate the spring hangers and balance the load across the VSM;
• Adjust the brackets and re-level the anchor platforms whenever the anchor platform exceeds 2 percent;
• Reposition the anchor slide plate to return the anchor to its proper alignment; and
• Adjust the elevation of the pipe shoes to increase the flexibility of the pipeline during pipe movement.

Many of these maintenance procedures are considered “covered tasks” under 49 CFR 195.501, Qualification of Pipeline Personnel. All steps of a procedure are mandatory and must be followed by pipeline maintenance personnel. Maintenance crew members must be qualified on the method of applying a procedure and on how to provide notification to the Operations Control Center, the local Maintenance Coordinator, the Control Room Operator, and the nearest upstream pump station prior to performing a procedure.

Based on these findings, RSPA/OPS grants Alyeska's request for a waiver of the requirements of § 195.424(a) for the aboveground portion of TAPS. The grant of this waiver is conditioned on the following items. Alyeska must—

• Apply this waiver only to the aboveground portions of TAPS;
• Apply this waiver during instances of routine pipe movement provided the pipe movement does not increase the stresses on the pipe;
• Not apply this waiver during instances where the pipe has fallen off the pipe supports due to seismic or hydraulic events, frost jacking, or dilapidated support structures; and
• Apply this waiver only during instances whenever routine maintenance necessitates the aboveground pipe be moved laterally, longitudinally or vertically, to relieve pipe stresses and restore the pipe to its intended position.

If Alyeska does not comply with any of these requirements, or if circumstances indicate that the waiver compromises the safety of the pipeline or of people or property, RSPA/OPS reserves the right to terminate the waiver.

Authority: 49 U.S.C. 60118(c) and 49 CFR 1.53.