Pipeline leak detection is complex and, while a range of technologies are available, operators would like the assurance of certification. They also need greater sophistication in choosing and deploying technologies.
These are some of the preliminary findings in the September draft "Leak Detection Study" prepared by pipeline safety consultants Kiefner & Associates, Inc. of Worthington, Ohio, for the federal Pipeline Hazardous Materials and Safety Administration. The PHMSA is a section of the U.S. Department of Transportation.
Congress mandated the report in the Pipeline Safety, Regulatory Certainty, and Job Creation Act of 2011 and asked that it cover technical limitations of current leak detection systems along with measures to foster better technologies and an analysis of the practicality of establishing standards for the capability of leak detection systems.
The current study updates PHMSA's December 2007 "Leak Detection Technology Study."
Following a review of past incident reports, inspections of systems and interviews with operators and equipment suppliers, Kiefner & Associates provided some preliminary observations in its 270-page draft report.
A leak detection system can be broken down into personnel, procedures and technologies, the researchers observed.
Different systems are appropriate for leaks, for ruptures and for seeps. One intended for ruptures doesn't have to be very sensitive but it should be very fast, they wrote, whereas one intended for leaks may take longer to detect a loss, but it should be sensitive and reliable.
The researchers found that systems currently in use are dominated by "pressure/flow monitoring" that takes advantage of supervisory control and data acquisition, or SCADA, systems already in place and by inexpensive "computational pipeline monitoring."
But pressure/flow monitoring will catch, at best, large ruptures, they wrote. And limitations of computational pipeline monitoring expose high–flow rate pipelines to large spills.
Despite the acknowledged shortcomings of these basic methods, operators are reluctant to upgrade to more complex methods. They are put off by large numbers of false alarms of some methods. In addition, they are concerned about the fact that certification ensuring minimum performance standards is lacking.
"The impact on operators is that they fear investing in leak detection systems, with potentially little benefit to show from them and no way to truly measure success in a standardized way," the draft report reads. "The result … is that leak detection is implemented cautiously, and incrementally, on measurement and other systems that are already in place and self-justified."
While cost-benefit ratios for these systems can be very good, the researchers found, operators need more sophistication in choosing and deploying technologies.
"Leak detection system complexity or high cost does not directly translate to better performance," they wrote. "Without a focus on all three — technology, people and procedures — a single ‘weak link' can render the overall system useless. In particular, even very simple technologies can be very effective, if they are backed up by highly skilled operators and well-designed procedures. Design choices need to be balanced with available and committed operating and maintenance resources."
The final report is due out early this year, the New York Times reported.
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