Pipeline Corrosion Control & Prevention

(source: Cost of Corrosion website)

The corrosion-related cost to the transmission pipeline industry is approximately $5.4 to $8.6 billion annually. This can be divided into the cost of failures, capital, and operations and maintenance (O&M) at 10, 38, and 52 percent, respectively. Although data management, system quantification through the use of global positioning surveys, remote monitoring, and electronic equipment developments have provided significant improvement in several areas of pipeline corrosion maintenance, there have been few basic changes in the approach to the management of corrosion on pipelines until recently. These changes have been in the development of risk assessment strategies and pipeline integrity management programs.

In the past few years, a number of high-profile pipeline failures (both liquid and natural gas) have refocused concern on pipeline safety. Public safety concerns have provided the driving force for new regulations governing pipeline operations. The most significant of these, from a cost point of view, is the requirement for pipeline inspections. In-line inspection (i.e., “smart pigging”) is the one most often discussed. The ability of this technique to find corrosion flaws larger than a certain size (10 percent of pipe wall thickness) makes it extremely valuable for locating flaws before they become critical and cause pipeline failure (either leaks or rupture). The major concern is that a “find it and fix it” mentality is pursued at the expense of corrosion prevention strategies. Both approaches are required to optimize the cost benefit of corrosion management programs. Operators may be tempted to adopt a “find it and fix it” attitude due to the significant cost of pipeline inspection, which is estimated to be as high as $35 billion over the next 5 to 7 years. If operators cut conventional corrosion O&M costs while pursuing pipeline inspection, corrosion prevention will suffer. Without a best practices corrosion prevention strategy, corrosion will continue and the cost of repairing a deteriorating pipeline will continue to escalate. Thus, a “find it and fix it” strategy utilizing in-line inspection at the expense of corrosion prevention may save money in the short term, but will greatly increase capital expenditures for pipeline replacement and major rehabilitation in the long-term.

Opportunities for Improvement and Barriers to Progress

Developing an optimum approach that includes both inspection and corrosion prevention strategies is critical to the future safety and the cost-effective operation of transmission pipelines. The overall goal of the pipeline industry must be to preserve the pipeline as an asset ($541 billion replacement cost). Corrosion consumes the asset, which cannot be recovered; this makes corrosion prevention a critical part of any strategy. Realizing that corrosion prevention will never be 100 percent effective, an inspection strategy (“find it and fix it”), in addition to the corrosion prevention strategy, is required for those pipelines that have a higher probability of corrosion. Significant savings are possible by optimizing the inspection and corrosion prevention strategies. In order to achieve such optimization, improved prediction models for both internal corrosion and external corrosion need to be developed. Inspection strategies should include all three currently available methodologies (in-line inspection, hydrostatic testing, and direct assessment), depending on the pipeline conditions.

Regulatory pressures can both be an effective driving force and a barrier to cost-effective engineering practices. The regulations should permit operators to implement integrity management programs that permit incorporation of developments, while allowing the use of any and all strategies available to the operator. Another barrier to the development of cost-effective programs is the increased costs associated with inspection strategies. There will be significant pressure to downplay existing corrosion prevention strategies in order to fund the new federally mandated inspection regulations. The current corrosion prevention strategies must be maintained while the inspection strategies are implemented. The corrosion prevention and inspection approaches must eventually be combined into a comprehensive cost-effective integrity management program.

Recommendations and Implementation Strategy

Corrosion prediction models need to be developed in order to more accurately determine inspection intervals and to prioritize the most effective corrosion prevention strategies. Development of new and improved inspection techniques is required to expand the capabilities of in-line inspection of flaws that cannot be currently detected and to improve resolution for existing tools.

Impact of Federal Regulations

In the future, pipeline operators may be faced with tough challenges due to the aging pipeline infrastructure and the new federal regulations that promote pipeline safety. The key to corrosion management will be to optimize the operational and maintenance costs in the face of a growing demand for pipeline safety. Two areas that will affect pipeline operational costs are pipeline personnel qualification programs and enhanced pipeline inspection programs. The costs associated with these programs are, for the most part, added to the existing programs that the pipeline operator has in place prior to 2000. The costs of these programs can be significant and optimization of the corrosion control program will be critical.

For more information see: www.corrosioncost.com