Internal Corrosion Direct Assessment Methodology for Liquid Petroleum Pipelines
|Publication Date:||7 November 2008|
This standard is intended to serve as a guide for applying the NACE LP-ICDA process to liquid petroleum pipeline systems.
The primary purposes of the LP-ICDA method are (1) to enhance the assessment of internal corrosion in liquid petroleum pipelines, and (2) to improve pipeline integrity.
The LP-ICDA methodology assesses the likelihood of internal corrosion and includes existing methods of examination available to a pipeline operator to determine whether internal corrosion is actually present or may occur. This methodology may be incorporated into corrosion integrity and risk management plans.
LP-ICDA uses flow modeling results and provides a framework to utilize those methods.
LP-ICDA was developed for pipelines that are normally fully packed with petroleum compound(s) that exists in an incompressible liquid state under normal pipeline operating conditions, with BS&W contaminations that are normally less than 5% by volume.
One benefit of the LP-ICDA approach is that an assessment can be performed on a pipe segment for which alternative methods (e.g., in-line inspection [ILI], hydrostatic testing, etc.) may not be practical.
LP-ICDA has limitations, and not all pipelines can be successfully assessed with LP-ICDA. These limitations are identified in the pre-assessment step.
The provisions of this standard shall be applied by or 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 or related practical experience,
are qualified to engage in the practice of corrosion control and
risk assessment on pipeline systems. Such persons may be (1)
registered professional engineers, (2) recognized as corrosion
specialists by organizations such as NACE, or (3) professionals
(i.e., engineers or technicians) with professional experience,
For accurate and correct application of this standard, it shall be used in its entirety. Using or referring to only specific paragraphs or sections can lead to misinterpretation or misapplication of the recommendations and practices contained herein.
This standard does not designate practices for every specific situation because of the complexity of internal conditions that may be present in various pipeline systems.
In the process of applying LP-ICDA, other pipeline integrity threats, such as external corrosion, mechanical damage, stress corrosion cracking (SCC), etc., may be detected. When such threats are detected, additional assessments, inspections, or both must be performed. The pipeline operator should utilize appropriate methods to address risks other than internal corrosion, such as those described in NACE standards (e.g., SP0204),1 ANSI(1)/ASME(2) B31.4,2 ANSI/ASME B31.8,3 API(3) 1160,4 ANSI/API 579,5 and BSI(4) 7910,6 international standards (e.g., DnV(5) RPF101), 7 and other documents.
This standard does not address specific remedial actions that may be taken when corrosion is found; however, the reader is referred to ASME B31.42 and other relevant documents (e.g., API 2200)8 for guidance.
(1)American National Standards Institute (ANSI), 11 W. 42nd St., 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 2000-4070.
(4) British Standards Institute (BSI), 389 Chiswick High Rd., London, United Kingdom W4 4AL.
(5) Det Norske Veritas (DnV), Veritasveien 1, 1322, Høvik, Oslo, Norway.