2010-1497. Pipeline Safety: Leak Detection on Hazardous Liquid Pipelines

AGENCY:

Pipeline and Hazardous Materials Safety Administration; DOT.

ACTION:

Notice; Issuance of Advisory Bulletin.

SUMMARY:

The Pipeline and Hazardous Materials Safety Administration (PHMSA) is issuing this Advisory Bulletin to advise and remind hazardous liquid pipeline operators of the importance of prompt and effective leak detection capability in protecting public safety and the environment.

FOR FURTHER INFORMATION CONTACT:

Alan Mayberry by phone at 202-366-5124 or by e-mail at [e-mail] regarding the subject matter of this Advisory Bulletin, or the Dockets Unit, 202-366-4453, for copies of this Advisory Bulletin or other material in the docket. All materials in this docket may be accessed electronically at http://dms.dot.gov. General information about the PHMSA Office of Pipeline Safety (OPS) can be obtained by accessing OPS's Internet home page at http://www.phmsa.dot.gov/​pipeline.

SUPPLEMENTARY INFORMATION:

Background

Pipeline leak detection is one of the many layers of protection in PHMSA's approach to protecting people and the environment. The federal hazardous liquid pipeline safety regulations require pipeline operators to deploy a comprehensive set of safety measures to protect the public and the environment including an effective means of identifying and responding to hazardous liquid pipeline leaks at the earliest possible time. Pipeline operators are continuously improving the cumulative performance of these interconnected layers of protections, including advances in leak detection systems. These protections include, but are not limited to: Customized leak detection technology deployment; periodic risk-based assessment and defect repair prioritized by environmental and safety consequences; corrosion management; pipeline right-of-way surveillance; public awareness activities resulting in enhanced citizen leak condition recognition and response; emergency preparedness and coordinated response, including ongoing liaison efforts with emergency responders; and a review and incorporation of lessons learned from accident analyses and investigations.

Recently, the National Transportation Safety Board (NTSB) issued a safety study on pipeline Supervisory Control and Data Acquisition (SCADA) systems (NTSB/SS-05/02). The number of hazardous liquid accidents investigated by the NTSB in which leaks went undetected after indications of a leak on the SCADA interface was the impetus for this study. The NTSB examined 13 hazardous liquid pipeline accidents that they investigated from April 1992 to October 2004. The conclusions made by the NTSB in the study reflected the importance of monitoring systems, promptly recognizing leak incidents, and minimizing damage with quick response. PHMSA encourages all hazardous liquid pipeline operators to review the safety study which is available on the NTSB webpage.

Under current regulations, all hazardous liquid pipeline operators are required to periodically patrol their pipeline right-of-ways. This effort is performed principally to guard against third-party activity that has the potential to damage the pipeline, and is also performed to detect very small leaks not detected by other means. Often, the leaking product has impacted vegetation or has pooled on the surface, and therefore leaves visual cues. Conducting these surveillance activities is very important, but they are not sufficient on their own to address all aspects of leak detection. Hazardous liquid pipeline operators are also expected to track product movement along the pipelines in order to ensure that all product going into the pipeline arrives at interim storage points, and eventually reaches its destination. This traditional and basic method of leak detection by tracking product movement is essential to an understanding of line balance. Relatively short pipelines, operating with a single source and a single destination, can usually perform this process rather simply, if adequate and timely information is made available. With these more simple pipelines, the line balance technique for leak detection can often be performed with manual calculations, without the need of a computerized process. Those pipeline operators with longer and more complex systems, with multiple sources and/or destinations, are more dependent on computerized processes to perform a thorough product tracking resulting in a leak detection process. The more complex a pipeline operation, especially when carrying numerous products through batch operations, the greater the need for a sophisticated leak detection process.

Currently, there are 421 hazardous liquid pipeline operators. Two hundred and twenty of the operators have pipelines less than 50 miles long, 96 operators have pipelines 50 to 250 miles long, and 105 operators have pipelines longer than 250 miles in length. Many of the operators with higher mileage have configured their pipelines into networks, sometimes collecting product from multiple sources and delivering product to multiple destinations, making the leak detection process complex. At the same time, we recognize that in some cases the engineering analysis performed on point-to-point pipeline systems has determined that installing a computer-based leak detection system does not offer substantial improvements in leak detection capability beyond that of a simple manual line balance calculation process.

Under 49 CFR 195.444, pipeline operators using a computer-based leak detection system are required to comply with API RP 1130. Pipeline operators who do not employ computerized leak detection still need to safely and effectively perform the basic process of monitoring flow and pressure to detect large pipeline breaks. The line balance processes incorporating SCADA or other technology are geared to find less obvious failures such as partial line breaks and smaller leaks not apparent in general flow and pressure monitoring. When a pipeline operator has determined or selected to use a traditional line balance process through manual calculation, it is PHMSA's expectation that these operators would have systems configured and staffed in such a manner as to routinely, safely and accurately perform this manual calculation process at a maximum of one-hour intervals. The appropriate interval should be determined by engineering review, but should not exceed one hour. This hourly process is especially important any time product is flowing; but since leaks can occur at any time, all unexplained meter movements or pressure changes should be promptly investigated to minimize potential leak durations even if a line segment is shutdown. In addition, operators need to ensure open and regular communication between all active source and delivery points along the pipeline, either through verbal communication or through the use of SCADA or other similar technology.

Operators of point-to-point hazardous liquid pipeline systems are obligated to have a prompt and effective means of detecting and responding to leaks. In order to ensure the safe and environmentally sound operation of their hazardous liquid pipelines, the operating plans and procedures required by the pipeline safety regulations should include the performance of an engineering analysis to determine if a computerized leak detection system is necessary and appropriate. If the analysis determines that a computerized leak detection system is unnecessary, the operator should perform a line balance calculation and review process at no greater than one-hour intervals whenever product is flowing through the line, and monitor for pressure changes, meter movement and tank level changes even when the line is not flowing. As part of the recordkeeping requirements under current regulations, operators must retain documentation from any related engineering analyses for the computerized leak detection and line balance considerations to demonstrate the thoroughness of review during an inspection.

II. Advisory Bulletin ADB-10-01

To: Owners or Operators of Hazardous Liquid Pipelines.

Subject: Leak Detection on Hazardous Liquid Pipelines.

Advisory: The Pipeline and Hazardous Materials Safety Administration (PHMSA) is advising and reminding hazardous liquid pipeline operators of the importance of prompt and effective leak detection capability in protecting public safety and the environment. In order to ensure the safe and environmentally sound operation of their hazardous liquid pipelines, the operating plans and procedures required by the pipeline safety regulations should include the performance of an engineering analysis to determine if a computer-based leak detection system is necessary to improve leak detection performance and line balance processes. If an operator that does not have a computer-based leak detection system performs an engineering analysis and determines that such a system would not improve leak detection performance and line balance processes, the operator should perform the periodic line balance calculation process outlined herein and take any other necessary actions required to ensure public safety and protect the environment.

Issued in Washington, DC, on January 19, 2010.

Jeffrey D. Wiese,

Associate Administrator for Pipeline Safety.