What’s big in pigging?

Patrick Porter, Past President of the Pigging Products and Services Association, examines pigging regulations and emerging issues in the US market.

The energy pipeline infrastructure in the US consists of 2.3 million miles of pipeline and transports almost 66 percent of the energy used in the US. Several major incidents focused both public and regulatory attention on the safety of pipelines – events that captured the publics’ attention and compelled the regulators to take an aggressive position.

The Department of Transportation (DOT) Pipeline and Hazardous Materials Safety Administration (PHMSA) has public responsibilities for safe and secure movement of hazardous materials to industry and consumers by all transportation modes, including the nation’s pipelines. PHMSA’s role has evolved in response to a dynamic environment. The Congress recognized the critical importance of pipelines to the Nation’s vitality when it passed the Pipeline Safety Improvement Act (PSIA) of 2002. PHMSA has aggressively responded to these new mandates. This Act was the turning point that ushered in the environment that guides the pipeline industry today and will continue to dominate pipeline integrity activities for the foreseeable future.

OPS have completed most of the work required under the PSIA to make the nation’s intricate network of gas and liquid fuel pipelines safer. The safety improvements include completion of a full-scale inspection of all large liquid pipeline operators, development of standards to evaluate qualifications of pipeline safety employees, and the creation of a national pipeline mapping system to help local officials keep tabs on safety efforts associated with local pipelines.

Federal and state actions completed since the passage of the act include:

• Establishment of regulations directing natural gas transmission operators to adopt and implement an integrity management program similar to regulations issued previously for operators of hazardous liquid pipelines.
• Completion of comprehensive integrity inspections of all large liquid pipeline operators.
• Development of a standard for federal and state pipeline inspectors to evaluate the qualifications of pipeline operators’ safety employees.
• Inspection of more that half of all inter- and intras-state pipeline operators for compliance with the new standard.
• Development and implementation of a five-year research and development plan for improved pipeline technologies, supported by the award of almost $8 million for three dozen research projects since March 2002.
• Cooperation with RSPA’s state partners and industry to develop a national consensus standard designed to require pipeline operators to evaluate and update their public education programs.
• Completion of the National Pipeline Mapping System to provide information to local officials on the location of pipelines.
• Provision of specialized training to federal pipeline inspectors on technologies used in, and reports generated from, in-line inspection devices used to test the integrity of a pipeline. These devices are known as ‘smart pigs’.

Pipeline safety has come a long way since the PSIA was passed four years ago. Both the industry and the regulators are committed to doing “whatever is necessary to ensure pipelines are safe for the communities they serve.” This philosophy will continue to direct activities in all areas of pipeline operation and pipeline safety.

Integrity Management Program
A key program introduced by the regulations is the Integrity Management Program for High Consequence Areas. The IMP Rule improves pipeline safety through new requirements for periodic testing, integrated evaluation of risk information, improved Federal/State oversight of operator integrity management programs and plans, and enhanced communication to communities.

Nothing has had a more dramatic affect on pipeline operations than the IMP rule. PHMSA is now enforcing regulation of integrity management programs for both hazardous liquid and natural gas transmission operators. A comprehensive inspection of large hazardous liquid operators has resulted in the elimination of over 20,000 time sensitive pipeline defects. An IMP rule for distribution networks is now in place and will lead to similar safety achievements in those systems. The key elements of an IMP plan are defined in the regulations and guidance is given on techniques and methods to achieve the expected results.

“An operator must assess the integrity of the pipeline by any of the following methods. The methods an operator selects to assess low frequency electric resistance welded pipe or lap welded pipe susceptible to longitudinal seam failure must be capable of assessing seam integrity and of detecting corrosion and deformation anomalies.

(A) Internal inspection tool or tools capable of detecting corrosion and deformation anomalies including dents, gouges and grooves.
(B) Pressure test conducted in accordance with subpart E of this part; (C) External corrosion direct assessment in accordance with §195.588; or
(D) Other technology that the operator demonstrates can provide an equivalent understanding of the condition of the line pipe. An operator choosing this option must notify the Office of Pipeline Safety (OPS) 90 days before conducting the assessment.”

This rule has had a dramatic affect on the providers of cleaning tools and equipment, inline inspection service providers and even current industry research.

Pipeline inspection
Increased focus on inline inspection (ILI) and data analysis has highlighted the need to properly prepare the pipeline for the inspection. The advanced ILI tools being used today have an optimum operating range. The cleanliness of the pipeline, the velocity of tool movement and other factors that can affect the quality of the data must be controlled. Cleaning pigs have changed to meet this new demand and ILI Service Providers and Operators are working cooperatively to ensure optimum conditions for the data collection aspect of integrity assessment.

Even more important than data collection is the need to analyze the ILI data to produce the most accurate information possible. The ILI report is now the foundation of many IMP plans. The results of the analysis must therefore be validated to ensure that the information being used to assess the pipeline is accurate. This validation task is complex and time consuming but it is necessary.

The primary method of validation is through field investigations of defects, which are measured and the results compared to the predictions of the tool. This is not as easy as it sounds. The Pipeline Operators Form (POF) issued requirements for ILI reporting and set standards for defect definitions. The American Petroleum Institute (API) drafted API 1163 detailing specifications for ILI tool validation. This validation process will continue to dominate the increasing level of field activities.

Emerging technologies
The ILI service providers are responding to the demands of the industry by introducing new technology to detect and quantify cracks, locate ERW seam problems and more fully evaluate mechanical defects. In addition, all of the ILI Service Providers continue to improve data display and analysis software.

Ultrasonic inspection tools
Reliable detection of crack-like defects constitutes a challenge for the pipeline inspection industry. Depending on the type of pipeline, pipeline material and operating condition, different types of cracks can occur, including stress corrosion cracking (SCC), fatigue cracks, and cracks in the weld and heat-affected zone of longitudinal or girth welds.

While ultrasonic technology (UT) is well understood and used widely to detect and assess cracks, it is an engineering challenge to implement on a free-swimming pipeline inspection tool. The first UT tools were developed to detect corrosion or wall thinning 3defects. This alone was a significant engineering accomplishment. Ultrasonic technology tools for crack detection are even more advanced and more difficult to apply. These tools use liquid-coupled ultrasonic transducers where each sensor is inclined at such an angle as to generate a refracted shear wave propagating through the pipe wall at an angle of 45 degrees. This shear wave is propagating in the circumferential direction, optimum to detect longitudinal features.

Circumferential magnetic fields
Magnetic Flux Leakage (MFL) is the most common technology used to inspect pipelines. It is robust, easy to apply and relatively well understood. MFL is only sensitive to features that present a significant obstruction to the applied field. The traditional axial field used in most MFL tools is not oriented to detect crack-like features that lay in the same direction as the applied field.

ILI service providers developed MFL tools that induce a circumferential magnetic field into the pipe wall. This field direction is optimized to detect longitudinal features and is now commonly used for long seam assessment and detection of longitudinal gouges.

Electro-Magnetic Acoustic Transducers
Conventional wet-coupled ultrasonic technology (UT) inspection systems work well if a suitable liquid coupling medium is present, but has limitations in gas pipelines. Inspection tools using a dry-coupled ultrasonic technology using Electro-Magnetic Acoustic Transducers (EMAT) have been introduced.

These tools are based on an electro-magnetic conversion resulting from the application of an eddy current within a static magnetic field. The Lorentz force and magnetostriction generated thereby lead to an interaction between the EMAT and the metal surface. This interaction in turn produces an acoustic wave within the material. Since the material being inspected acts as its own transducer, the need for a liquid couplant is eliminated. Crack features such as stress corrosion cracking (SCC) disturb the guided wave, thereby producing an echo. On the basis of the detection and measurement of this echo, the features and condition of the pipe wall can be accurately inferred. This technology is used for detecting cracks and coating disbondment in both liquid and gas pipelines.

Mechanical damage
Demographic changes taking place requires increasing vigilance. Urbanization of previously rural areas is placing people closer to pipelines. Expansion and development also means more construction activity near pipelines. It should come as no surprise therefore that third-party excavation damage is a leading cause of pipeline accidents.

This is a focal point for PHMSA. Operators are required to assess and mitigate this risk and PHMSA is sponsoring development of new technology to help the industry address this issue. A recent industry initiative, sponsored by DOT, is aimed at development a multiple level magnetic field technique to detect and quantify mechanical damage. The multi-level magnetic fields may allow stress perturbation surrounding mechanical features to be detected. This could ultimately lead to better methods to assess the significance of these features.

Several ILI service providers have introduced advanced ILI equipment using multiple technologies to better assess all detected features and specifically to quantify mechanical defects. The designs include sensors for low level magnetic field, high level magnetic field, high-resolution deformation, inertial positioning, bend measurement, ID/OD discrimination plus additional sensor to acquire the data necessary to assess the condition of a pipeline.

Stress at mechanical features can be detected by using both high and low level magnetic fields. When these data are decoupled, the effects of stress remain. The decoupled data is then compared to the deformation and inertial data to provide an assessment of the feature.

Data from each data set provides a unique view of the condition of the pipe. When the data sets are viewed concurrently, features can be far more accurately assessed than would be possible from any single data set or even any two data sets.

Emerging issues
To manage the risks inherent in pipeline transportation, PHMSA has been building a more comprehensive and informed approach to pipeline safety consistent with the PSIA. This initiative will continue to direct integrity activities in the immediate future. This plan is based on improving pipeline performance by: managing risk, sharing responsibility and providing effective stewardship.

The bar on safety has been raised. By collecting and using better information about pipelines, we know more about pipelines, the world they traverse, and the consequences of a pipeline failure. By strengthening our ability to better collect and analyze data, we can better characterize safety issues and highlight pipeline operators with performance concerns. These are the issues that will direct integrity activities in the near future.

PHMSA has strengthened its partnerships with State pipeline safety agencies through increased policy collaboration, better training, shared databases, and a distributed information network to facilitate communication. In partnership with the State inspectors, PHMSA is working to deliver better oversight in accordance with higher standards.

PHMSA has taken advantage of higher penalty authority and have institutionalized a tough-but-fair approach to enforcement. They are imposing and collecting larger penalties, while guiding pipeline operators to enhance higher performance. PHMSA has identified several performance measures to track the impact of enforcement efforts, such as the severity of inspection findings. Compared to 2003, the first year when higher penalty authority was available, PHMSA doubled the civil penalties proposed in 2004 and tripled them in 2005. For calendar year 2005, the proposed penalties amounted to over $4,000,000.

To improve the technology available to assess and repair pipelines, PHMSA has invested over $22 million in technology research and development since 2002 and leveraged an additional $26 million in investments from the private sector. These investments have jump-started more than 80 projects across the country.

DOT has requested, and the Congress has appropriated, 24.5 percent more resources since 2002 to help implement the plan to improve pipeline safety.

New focus
A key issue for pipeline safety is damage prevention. Helping communities know how they can live safely with pipelines by preventing damage to pipelines is a very important goal.

PHMSA is working with the Common Ground Alliance (CGA) on all damage prevention efforts, leading many stakeholders to share responsibility for damage prevention. The three-digit dialing of 811, required in the PSIA, will be implemented in the near future. This will provide a single uniform action that all Americans can take to improve safety.

Through rulemaking, PHMSA is addressing the mandate of protecting unusually sensitive areas from risks posed by rural liquid gathering lines and low stress transmission pipelines.

Stronger oversight will continue to be an important strategy in strengthening pipeline safety. In the past 12 years, the OPS has added 60 inspectors to PHMSA’s pipeline safety staff. PHMSA’s state agency partners employ over 400 additional inspectors who oversee 90 percent of the infrastructure.

As the first round of IMP audits comes to a close, expectations of performance have increased. PHMSA inspectors have learned the same lessons as the operators and will use this new knowledge in future inspections and performance audits. Compliance to the regulations and the documentation necessary to demonstrate that compliance will get more demanding.

Research and development
Over the past three years, PHMSA has built a research and development program that has funded 80 projects at a cumulative expense of nearly $50 million to address better diagnostic tools, testing of unpiggable pipes, stronger materials, improved pipeline locating and mapping, prevention of outside force damage, and leak detection.

R&D activities are focused on near-term technology development needs and supporting technology demonstrations such as remote sensing of gas leaks and internal inspection of unpiggable pipes.

The future
Looking forward, PHMSA will continue to drive the majority of pipeline integrity activities with special emphasis on damage prevention and its philosophy of a tough-but-fair approach to enforcement will go on. Meanwhile operators will develop procedures and processes that comply with the IMP rule and demonstrate compliance through detailed documentation.

Integrity management is likely to become more effective because of the continuing improvement processes and measurable performance built into the system, while defect assessment will become a high priority issue.

ILI service providers will become directly involved in all field activities related to tool validation in the future, which will close the feed-back loop and generate the information needed for improvements in data analysis. We expect a more cooperative relationship to develop to the benefit of all parties.

With improvements in analysis algorithms and accuracy, operators will see the value of looking directly at the ILI data and comparing it to as-built information. This alone will improve the record of the pipeline and increase safety.

We will also see ILI Service Providers will continue to develop the technology that the industry demands. Every ILI provider has made significant progress in the last year. If you think you are up-to-date and knowledgeable on current ILI technology I suggest you contact your selected Service Provider and ask them, ‘what is new?’ I think you will be surprised. Over all, the industry is responding admirably to the current challenges. The cooperative environment that has developed is the key to success and is the only way to ensure continued improvement.