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Interpretation Response #PI-83-005 ([ADB 83-2])

Below is the interpretation response detail and a list of regulations sections applicable to this response.

Interpretation Response Details

Response Publish Date:

Company Name: ADB 83-2

Individual Name:

Country: US

View the Interpretation Document

Response text:



49 CFR Part 192

(Interpretations 83-1, 83-2)

Transportation of Natural and Other Gas by Pipeline; Corrosion Control Monitoring

AGENCY: Materials Transportation Bureau (MTB)

ACTION: Interpretation

SUMMARY: Operators of gas pipelines are required by 49 CFR §192.465 to monitor their pipelines for corrosion control purposes. Questions have risen in the enforcement of this regulation about its application to (1) cathodic protection that has been voluntarily installed, and (2) pipelines in remote areas. Agency interpretations provide that (1) pipelines with voluntarily installed cathodic protection are subject to the 3-year re-evaluation requirements but not the annual monitoring rule, and (2) electrical surveys are not required for pipelines in remote areas if it can reasonably be concluded that corrosion-caused leaks in those areas would not be detrimental to public safety.

EFFECTIVE DATE: (Insert date of publication in the Federal Register)



Interpretation 83-1

Section: 192.465(a)

Subject: Monitoring cathodic protection that is voluntarily installed.

Facts: None.

Question: In Amendment 192-35 (44 FR 75384, December 20, 1979), which permitted short sections of cathodically protected transmission lines to be tested on a sampling basis, the Materials Transportation Bureau stated that the "regulation applies to pipelines that are separately protected by the 'hot spot' method." Does this mean that anodes an operator voluntarily installs whenever a pipeline is uncovered are subject to the testing requirements of §192.465(a)?

Interpretation: Section 192.465(a) requires, in part, that each pipeline that is under cathodic protection must be tested "to determine whether the cathodic protection meets the requirements of §192.463." In §192.463, paragraph(a) prescribes the level of cathodic protection that each cathodic protection system "required by this subpart" (Subpart I of Part 192) must provide. The reference to the requirements of §192.463, which, consistent with §192.463(a), only apply to cathodic protection systems that are required by Subpart I, strongly implies that the testing requirements of §192.465(a) only apply to pipelines on which cathodic protection is required by Subpart I. There does not appear to be any contrary intent from our reading of the history of §192.465(a) and Subpart I. Further, to apply the testing requirements to voluntarily installed anodes (or cathodic protection that is not required by Subpart I) would tend to discourage voluntary practices that are in the interest of public safety. Pipelines on which anodes have been voluntarily installed would, however, be subject to the 3-year re-evaluation requirements of §192.465(e) which by logical extension of the above reasoning, apply to pipelines that are not cathodically protected as required by Subpart I.

Interpretation 83-2

Section: 192.457(c) and 192.465(e)

Subject: Electrical surveys in remote areas.

Facts: None

Question: In the case of cathodically unprotected pipelines located in remote areas, must an electrical survey be performed, where practical, as part of the 3-year re-evaluation required by §192.465(e), even though circumstances indicate that any corrosion found by the survey would not be expected to endanger public safety?

Interpretation: The purpose of §192.465(e) is to require that cathodic protection be installed where "active corrosion" exists on unprotected pipelines. The term "active corrosion" is defined in §192.457(c) to mean "continuing corrosion which, unless controlled, could result in a condition that is detrimental to public safety." As this definition implies, there are segments of pipelines on which continuing corrosion would not endanger public safety. Indeed, the preamble to Amendment 192-4, which established §§192.457(c) and 192.465(e), makes it clear this implication is intended by the definition of "active corrosion." Such segments might be found in remote locations or other places where because of the pipeline's distance from people, it is not reasonable to foresee that corrosion or, worse, a corrosion-caused leak would be detrimental to public safety. Similarly, corrosion determined to be progressing so slowly that leakage would not result before the next 3-year re-evaluation would not be detrimental to public safety.

Because §192.457(b) as well as §192.465(e) requires the use of electrical surveys in determining the existence of active corrosion, the Office of Pipeline Safety Operations stated in a 1976 interpretation (41 FR 29128) that an electrical survey is the first step in finding active corrosion. As a result, operators have had to conduct surveys on pipelines located in remote areas even though corrosion-caused leaks in those locations would not be considered detrimental to public safety.

We believe that to blindly run electrical surveys in areas where existing and reasonably foreseeable circumstances show that corrosion-caused leaks would not be detrimental to public safety is inconsistent with the "active corrosion" definition. Therefore, we will no longer apply the 1976 interpretation on this subject. Instead, in complying with the 3-year re-evaluation required by §192.465(e), operators may, first, consider all factors relevant to determining whether a corrosion-caused leak occurring within the 3 years before the next re-evaluation would be detrimental to public safety. Then, in areas where it is reasonable to foresee that such leaks would be detrimental to public safety, §192.465(e) requires that electrical surveys be run, if practical, to look for continuing corrosion and that cathodic protection be applied where continuing corrosion is found.

(49 USC 1672 and 1804; 49 CFR 1.53, Appendix A to Part 1, and Appendix A to Part 106)

Issued in Washington, D.C. on_______________________________.

Richard L. Beam

Associate Director for

Pipeline Safety Regulation

Materials Transportation Bureau

Regulation Sections

Section Subject
192.461 External corrosion control: Protective coating
192.463 External corrosion control: Cathodic protection