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U.S. Department of Transportation U.S. Department of Transportation Icon United States Department of Transportation United States Department of Transportation

Interpretation Response #PI-77-025 ([Florida Public Service Commission] [Harold E. Janes])

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

Interpretation Response Details

Response Publish Date:

Company Name: Florida Public Service Commission

Individual Name: Harold E. Janes

Location State: FL Country: US

View the Interpretation Document

Response text:

November 10, 1977

Mr. Harold E. Janes
Director - Engineering Department
Florida Public Service Commission
700 South Adams Street
Tallahassee, FL 32304

Dear Mr. Janes:

Your letter dated May 20, 1977, to Mr. J. C. Thomas concerning Information Bulletins GS-26 and GS-26A sent to all gas system operators under jurisdiction to the Florida Pubic Service
Commission (PSC) has been sent to this Office for response.

Based on our review, we find that the guidelines for electrical survey contained in the bulletins are inconsistent with the Office of Pipeline Safety Operations' (OPSO) interpretations of 49 CFR Section 192.457 concerning electrical surveys (copy enclosed). Under Section 192.457(b), an operator must use an electrical survey method which identifies all areas of continuing corrosion along a pipeline with enough detail so that the operator can determine whether a condition detrimental to public safety could result.

Although we have no objection to the intent of the bulletin, we recommend that you consider the following:

* With regard to soil resistivity surveys, the intervals specified in the guidelines are misleading and are not adequate for some pipelines. It would be difficult to meet compliance with 49 CFR Section 192.457 using these guidelines.

* With regard to the Florida PSC recommendation that "P/S potential measurements need not be made in soils of resistivity above 50,000 ohm-cm, unless the operator has knowledge of environments or corrosion leak histories which warrant investigation in high resistivity environments," this encourages noncompliance with the electrical survey requirement. Furthermore, pipelines do corrode at resistivities higher than 50,000 ohm-cm.

* With regard to the Florida PSC recommendation that "Corrosion control is only recommended on underground pipelines which lay [sic] in soils of resistivity of 50,000 ohm-cm or less when the combination electrical survey indicates that active corrosion does exist," OPSO has not received any information or evidence to show that active corrosion does not exist on pipeline buried in resistivities higher than 50,000 ohm-cm.

Mr. George Mocharko of my staff has discussed this matter with your Mr. Lamar Cockrell. If you have any additional question, please advise.


Cesar DeLeon
Acting Director
Office of Pipeline
Safety Operations


Regulation Sections

Section Subject
192.457 External corrosion control: Buried or submerged pipelines installed before August 1, 1971