Data from US pipeline performance tracking begin to yield clearer picture

In the 5 years from 1968 through 1972, the pipeline system averaged 377 reportable incidents/year, with an annual volume spilled of 366,000 bbl. In the most recent 5 years, 1997 through 2001, the average number of incidents per year and the average annual volume spilled were both approximately 60% lower, at 154 incidents and 144,000 bbl, respectively.

In addition, the amount of oil transported by pipeline increased by 42% over the period, from an average of about 3,000 billion bbl-miles/year during the earlier period to about 4,300-billion bbl-miles/year during the latest period. (1 bbl x 1 mile = 1 bbl-mile)

The volume lost per barrel-mile has therefore fallen by more than 70%. And 2000 and 2001, both setting new lows for the number of incidents and volume spilled, look to be the start of a trend for even better performance.

But the oil pipeline industry cannot live on its past. Operators must find the correct solutions to reach the goal of eliminating pipeline accidents. In 1998, the leadership of the oil pipeline industry concluded that lack of data had prevented operators, collectively, from learning all they could or needed to learn from pipeline accidents. These accidents included not only the rare large spills or the spills that met the reporting criteria imposed by the US Department of Transportation's Office of Pipeline Safety, but all spills down to those as small as 5 gal.

(OPS regulates oil pipelines under 49 CFR [Code of Federal Regulations] Part 195. Until early 2002, the industry reported any incident that involved spills of 50 bbl or more, death, injury, fire, explosion, or damage of $50,000 or more. OPS' reporting system was substantially revamped earlier this year, lowering the volume-reporting threshold from 2,100 gal to 5 gal and greatly increasing the level of detail reported on causes and consequences.)

PPTS

The oil pipeline industry, through various committees and reviews, created the Pipeline Performance Tracking System (PPTS) as one of the linchpins of industry's environmental and safety initiative, a multidiscipline approach to understanding and improving industry performance.

The availability of more-detailed data is crucial to that objective. Although many individual operators had developed stringent internal reporting criteria, there were no industry-wide aggregations with the necessary amount of detail to provide lessons learned.

The pipeline leadership, framers of PPTS, widely distributed in 1999 an invitation to participate in the voluntary pipeline performance tracking system (PPTS).

By the end of 2001, 35 corporate operators had submitted 2 years of information on 53 separate systems. The operators were reporting on more than 140,000 miles of pipe. Compare this with the 157,000 miles on which OPS collects user fees (PPTS is about 90%) and the total oil pipeline mileage, including gathering lines, of 200,000 miles (PPTS represents nearly 75%).

PPTS operators transport 3.8 trillion bbl-miles of crude oil, refined product, NGL, and CO2, about 90% of the estimated US total of 4.3 trillion bbl-miles.

Participating operators report spills of 5 gal and more, plus any smaller spills to water. Each participant enters the information into API's database, and each participant's data remain confidential.

PPTS requests relatively few details on spills less than 5 bbl that do not involve a death, injury, fire, or explosion. There are some basics reported, however:

• Was the spill onshore or offshore?
• Did it have an impact beyond company-controlled property?
• What type of water impact (if any) did it have?
• What part of the system was involved (onshore pipe, for instance, vs. facility piping and equipment)?
• What was the cause of the spill, under the seven first-level causes?

Beginning in 2002, operators are also reporting on whether each release affects a "high-consequence area," the new regulatory delineation based on an area's population, environmental sensitivity, or commercial navigation.

In contrast to the limited detail for spills smaller than 5 bbl, the system records enormous detail for those incidents of 5 bbl or more or ones that involve a death, injury, fire, or explosion.

This wealth of information in PPTS is one of its more important and impressive features, allowing analysts to "drill down" to see the conditions surrounding a release and thus more effectively to learn how to prevent future releases. This benefit will grow as additional years of data are entered into the database, providing more information and more robust conclusions about patterns and risks.

Understanding risks

The framers of PPTS focused on risks and the implications for operational decisions in designing the PPTS questionnaire and its classifications. For example:

•PPTS covers transported commodities (crude oil, refined product, NGL, CO2) and provides breakdowns by those commodities so that risks and risk reductions can be better targeted.

•PPTS provides detailed information related to the part of the system that failed. PPTS allows for analysis of line pipe incidents and explicitly separates tanks (the storage vessel) from piping or other equipment at terminals, breakout locations, or pumping station. Offshore pipe is separated from onshore pipe.

The distinctions are critical to evaluations of risk in different parts of the system. For instance, 3 years of data have quickly demonstrated that incidents involving tanks are very few, even though incidents involving the piping and equipment at pump stations and tank farms are more common.

•PPTS also uses spill-cause categories that reflect risk. All releases are categorized into seven first-level causes: corrosion, equipment or non-pipe failure, natural forces, operator error, pipe material or weld failure, third-party damage, and other causes. For spills of 5 bbl and more, PPTS further breaks down the cause categories, allowing for finer and finer analysis.

For spills of 5 bbl and more, each first-level cause has a "drill-down" page that seeks additional detail. For example, the corrosion details in PPTS aim at identifying the impact of risk factors. Although many risk factors have been understood by engineers and operators, until PPTS was created, there were no industry-wide data on specific subjects such as whether a pipeline that experienced a release was operating at greater than 100° F. or whether it might have been affected by a road crossing casing.

PPTS will allow analysis both to support engineering judgment and to correct misperceptions. PPTS will provide answers to specific technical questions and improve the industry's understanding of corrosion risks, direct vendor efforts at identifying specific kinds of anomalies in pipe, and help the industry in general assess and mitigate risk in construction and operation.

Over the first few years of data collection, API has been focusing on quality control of the data and developing potential analytical frameworks and testing those frameworks. Although only one major report has been completed based on PPTS information to date, a few conclusions have emerged from the first 3 years of data, none of which could have been confirmed before and some of which were surprising.

•Although the number of spills that are smaller than 50 bbl represents a multiple of those formerly reported under OPS' 50-bbl threshold, they represent a tiny share of the total PPTS volume. From 1999-2001, PPTS responses show that about 15% of the incidents would have met the OPS reporting threshold of 50 bbl, but these larger incidents accounted for 96% of the volume spilled.

Put another way, collecting information on all those small spills–down to 5 gal and all spills to water–provided a nearly seven-fold increase in the opportunities to learn from releases but added less than 4% to the volume reported.

•Most spills, large or small, do not affect water of any kind—neither surface water, groundwater, drinking water, nore commercial navigation (Table 1).

In another example, the new PPTS detail on third-party incidents will help the industry focus its efforts on prevention. (Third-party incidents are caused by parties unrelated to the pipeline operator and account for the highest share of volume lost from line pipe. Because of their importance to all kinds of pipelines, not only oil pipelines, these incidents are the focus of extensive damage-prevention efforts.)

•Not only does PPTS separate third-party incidents into damage at the time, previous damage, vandalism, and fires, it also asks about the "damaging party," that is, what kind of activity (or actor) caused the damage.

It has been commonly assumed that "third-party" damage is shorthand for "excavation" damage, a hit from a backhoe or other equipment used during excavation activities. A surprising note from the first 3 years of PPTS data is that farming activities and other underground facilities operators (including other pipeline operators) are more likely to cause third-party damage than conventional excavators.

With only 3 years of data, the volume data, in particular, are skewed by a few large incidents. But with additional data, operators will be able to target specific prevention efforts more effectively (for example, outreach to specific potential third parties, such as farmers).

Another issue in which PPTS provides a first-ever look is leak-detection capabilities. The technical challenges of finding small leaks vs. large leaks are different, of course. PPTS asks for information on leak detection (how a release was found) as well as leak confirmation (whether a leak-detection system worked according to design).

•This is an example in which the industry worked to refine the questions after the first year, thinking that participants did not understand the data fields, as defined. The descriptions were clarified for 2000, with the help of various API pipeline committees, including the cybernetics committee.

One of the conclusions based on the data so far is that, basically, people find leaks–local operations personnel (people in the field) or third parties. This is an area in which the size of the leak makes a difference, however.

"Combined rates of change" and other similar information available to control room personnel on their consoles, for instance, are not going to show smaller leaks at all, and changes will not be apparent instantaneously even for larger leaks. Similarly, the contribution of leak-monitoring systems based on supervisory control and data acquisition (SCADA) systems is in finding large leaks, not generally small ones.

("Combined rates of change" is a simultaneous measure of the pressure and flow in the line or another device.)

This is another example of a PPTS element that we will be watching closely to see if there are shifts over the next few years and to explore the data in more depth. For instance, leak-monitoring systems are likely to become more widely used and more finely calibrated, enabling them to find smaller leaks and to find leaks on more systems (Fig. 2).

Trends

In addition to information about incidents, PPTS also collects information on the participants' infrastructures. Only with information about both incidents and incident-free pipeline miles can trends be evaluated. PPTS collects:

• Miles of pipe onshore and offshore.
• Miles of pipe by commodity transported.
• Miles of pipe by diameter.
• Miles of pipe by decade of construction.
• Miles of pipe by state.
• Volume transported by commodity (barrel-miles).
• Miles inspected.
• Tanks, meter stations, pumping stations.

The PPTS data on the mileage by decade represent an inventory of the pipe currently in the ground. By mid-2001, operators had provided information on 143,600 miles of pipe by decade.

The data allowed PPTS analysts to graph the pattern that the industry knew but could not quantify: The 1950s and 1960s were the decades accounting for the construction of the largest shares of pipeline miles now in the ground, at 22% and 23%, respectively, and the 1970s, the third-ranked decade, accounted for the construction of 17% of the pipeline miles.

The decade-of-construction data provided an opportunity to do a first-ever analysis of pipeline characteristics and performance by decade of construction.

The PPTS is not a static data collection effort. Changes have already been incorporated to provide data to measure the effectiveness of the new integrity management rules for oil pipelines. (These rules, at 49 CFR Part 195.452, establish a framework of risk assessment, inspection, repair, and maintenance.)

PPTS will ask whether incidents occurred in the "high consequence areas" defined in the rule. PPTS will also collect information on the total mileage inspected using various in-line inspection tools and hydrostatic tests and the number and types of repairs completed based on the results.

As of 2001, PPTS also began collecting information on the miles of pipe on which baseline assessments under the integrity-management program had been completed, thus providing an ongoing scale of progress under the program.

Reporting

The PPTS has provided new opportunities for communication with government agencies such as OPS and the National Transportation Safety Board. Experience with PPTS also allowed the industry to offer more constructive suggestions as OPS developed rulemakings on integrity and on performance measurement.

Finally, the availability of high-quality data and in-depth analysis allows the industry to debate policies from a sound, demonstrable position, not speculation or conjecture.

The committee that oversees PPTS analysis, the data mining team, is developing a series of topical memoranda that will help anyone seeking background on the system or on the industry in general. Topics of these brief reports include the industry's spill record and the role of PPTS and the role and impact of small spills, among others.

Finally, the primary purpose of PPTS is its role as a tool for the industry. Using PPTS, industry operators, vendors, and contractors will better understand risks. PPTS provides new and crucial detail on both the probability and the consequence side of the risk equation.

Risk assessments and models can be populated by more specific data. Operators will be better able to target prevention efforts, as well as awareness programs.

The first full report that used PPTS data as a springboard was completed late last year.

Analytical work based on industry performance at the level of detail provided by PPTS will provide operators with the information they need to further reduce pipeline incidents.

The authors

Cheryl. J. Trench established Allegro Energy Consulting in 1997 after 22 years analyzing the oil industry and its markets for the Petroleum Industry Research Foundation where she served in a variety of capacities including director of research and executive vice-president. She is a member and past chapter president of the International Association for Energy Economics and serves on the advisory board for New York University's Energy Forum. Trench holds a BA in economics from the City University of New York.

Marty Matheson is general manager for pipelines at the American Petroleum Institute, Washington, DC, where she has worked for 26 years with tours of duty in standards development, refining, truck and rail transportation, as well as pipeline. She is now part of API's management team. Matheson holds a BA from St. Lawrence University and is a member of ASME and its B31.4 committee.