Quick Facts:
- Corrosion is the natural process of materials made from metal to their original state through a chemical reaction known as oxidation.
- Corrosion is one of the leading causes of pipeline leaks and ruptures.
- Improved technologies have led to better prevention, monitoring, detection, and mitigation of pipeline corrosion – even for old pipelines.
- New pipeline Integrity Management regulations will promote early identification of potentially corroded sections and their repair.
- Refer to other Fact Sheets for specific discussion of issues related to internal corrosion, external corrosion, selective seam corrosion, and stress corrosion cracking.
What is corrosion and why does it occur?
Corrosion is the deterioration of metal that results from a reaction with the environment which changes the iron contained in pipe to iron oxide (rust). For example, if your car develops a rust spot, that is corrosion of metal. The same process can occur in various forms on pipelines. As is the case with your car, there are effective methods for preventing and arresting corrosion damage to pipelines.
- External corrosion occurs due to environmental conditions on the exterior surface of the steel pipe (e.g., from the natural chemical interaction between the exterior of the pipeline and the soil, air, or water surrounding it).
- Internal corrosion occurs due to chemical attack on the interior surface of the steel pipe from either the commodity transported or other materials carried along with the commodity transported within the pipeline.
- Other, more specialized types of corrosion such as stress corrosion cracking , microbial corrosion, and selective seam corrosion can also occur. These types of corrosion can be exacerbated by environmental conditions, manufacturing processes and applied stresses resulting from routine and normal pipeline operations.
What are the risks from corrosion?
Corrosion can result in the gradual reduction of the wall thickness of the pipe and a resulting loss of pipe strength. This loss of pipe strength could then result in leakage or rupture of the pipeline due to internal pressure stresses unless the corrosion is repaired, the affected pipeline section is replaced, or the operating pressure of the pipeline is reduced.
Pipeline corrosion creates weaknesses at points in the pipe, which in turn makes the pipe more susceptible to third party damage, overpressure events, etc. (i.e., corrosion doesn't necessarily need to cause the leak or rupture itself to increase risk).
Pipeline Failure Rates from Corrosion
Corrosion is one of the most prevalent causes of pipeline spills or failures. For the period 2002 through 2003, incidents attributable to corrosion have represented 25% of the incidents reported to OPS for both Natural Gas Transmission Pipelines and Hazardous Liquid Transmission Pipelines.
Over this same period, approximately 1 percent of the incidents reported to OPS for Gas Distribution Pipelines were due to corrosion.
What is being done to prevent/mitigate corrosion?
- Modern manufacturing processes for steel pipe and their protective coatings are subject to rigorous fabrication and installation standards and quality control to reduce the occurrence of defects that can lead to corrosion-induced failures.
- Operators use coatings, cathodic protection systems, pipe cleaning techniques, product quality controls, and other approaches to protect pipelines from corrosion.
- The Office of Pipeline Safety has implemented new Pipeline Integrity Management (“IM”) regulations that require all pipeline operators to inspect and assess all of their pipelines that could affect areas of high consequence such as populated areas or environmentally sensitive areas. The operators are required to inspect and assess their pipelines for integrity issues, such as corrosion, and repair or replace affected pipe.
- By implementing the requirements of the regulations and through responsible maintenance programs, pipeline operators continuously inspect their pipelines for corrosion damage and potential susceptibility.
Corrosion: What more can be done
- Public: Be aware of pipelines located near you. Be observant for signs of pipeline damage, leakage, or security concerns. Report any concerns you have regarding pipeline safety to the pipeline operator immediately. Always respect the pipeline right-of-way. Do not dig or build on a pipeline right-of-way without first contacting the pipeline operator or your state one-call center.
- Industry: Pipeline operators and industry stakeholders can continue to develop and implement improved corrosion detection and prevention technologies. Operators must continue to implement corrosion protection effectively and strengthen pipeline integrity management programs. Operators must mitigate the effects of corrosion when it is detected.
- Regulators: OPS and state regulators must continue to inspect pipeline operators to ensure they effectively implement required integrity management and corrosion control programs to ensure that risks to pipelines are identified and mitigated at the earliest possible time. Better coordination is needed between local permitting agencies and pipeline operators to facilitate expeditious granting of permits when public safety is potentially threatened.
Corrosion: Where can I learn more?
- Public: Be aware of pipelines located near you. Be observant for signs of pipeline damage, leakage, or security concerns. Report any concerns you have regarding pipeline safety to the pipeline operator immediately. Always respect the pipeline right-of-way. Do not dig or build on a pipeline right-of-way without first contacting the pipeline operator or your state one-call center.
- Industry: Pipeline operators and industry stakeholders can continue to develop and implement improved corrosion detection and prevention technologies. Operators must continue to implement corrosion protection effectively and strengthen pipeline integrity management programs. Operators must mitigate the effects of corrosion when it is detected.
- Regulators: OPS and state regulators must continue to inspect pipeline operators to ensure they effectively implement required integrity management and corrosion control programs to ensure that risks to pipelines are identified and mitigated at the earliest possible time. Better coordination is needed between local permitting agencies and pipeline operators to facilitate expeditious granting of permits when public safety is potentially threatened.
Corrosion: Where can I learn more?
Date of Revision: 120104