Pipeline Integrity Method Selection
|Publication Date:||16 March 2013|
Corrosion integrity assessment is a process for improving pipeline safety. Its primary purpose is to prevent future corrosion damage.
For accurate and correct application of this standard, the standard shall be used in its entirety. Using or referring to only specific paragraphs or sections may lead to misinterpretation and misapplication of the recommendations and practices contained herein.
This standard provides the evaluation methodology, but does not designate practices for every specific or unique situation because of the complexity of conditions to which buried piping systems are exposed.
This standard presents a methodology for the selection of integrity assessment methods for external corrosion, internal corrosion, and SCC on onshore ferrous pipelines carrying natural gas and hazardous liquids.
This standard provides flexibility for the pipeline operator to tailor the corrosion integrity assessment method to specific pipeline situations.
This methodology is a continuous improvement process. Through periodic successive assessments, the process should identify and address locations at which corrosion activity has occurred, is occurring, or may occur, and show the effectiveness of various mitigation programs.
This methodology provides the advantage and benefit of locating areas in which corrosion wall loss may form in the future rather than only areas in which corrosion defects have already formed.
Comparing the results of the successive periodic assessments is one method of evaluating the integrity assessment process, determining the effectiveness, and demonstrating that confidence in the integrity of the pipeline with respect to the corrosion threats continuously improving.
The individual integrity assessment processes may detect pipeline integrity threats other than EC, IC, and SCC, such as mechanical damage, microbiologically influenced corrosion (MIC), etc. When such threats are detected, additional assessments and inspections should be performed. The pipeline operator should utilize appropriate assessment methods such as those listed in ANSI(1)/ASME(2) B31.4,1 ANSI/ASME B31.8,2 ANSI/ASME B31.8S,3 and API(3) 11604 to address each of these other risks.
Each integrity assessement method complements the others. They do not have identical performance, but each has advantages over the others. All pipelines may be successfully assessed with just one particular method. Precautions should be taken when applying these methodologies, just as with other assessment methods, in order to choose what is most appropriate.
The provisions of this standard should be applied under the direction of competent persons who, by reason of knowledge of the physical sciences and the principles of engineering and mathematics, acquired by education and related practical experience, are qualified to engage in the practice of corrosion control and risk assessment on buried ferrous piping systems. Such persons may be registered professional engineers or persons recognized as corrosion specialists or cathodic protection (CP) specialists by organizations such as NACE or engineers or technicians with suitable levels of experience, if their professional activities include external corrosion control of buried ferrous piping systems.
(1) American National Standards Institute (ANSI), 25 West 43rd St., 4th Floor, New York, NY 10036.
(2) ASME International (ASME), Three Park Ave., New York, NY 10016-5990.
(3) American Petroleum Institute (API), 1220 L St. NW, Washington, DC 20005.