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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-72-016 ([CONAM Inspection, Inc.] [David A. Warren])

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

Interpretation Response Details

Response Publish Date:

Company Name: CONAM Inspection, Inc.

Individual Name: David A. Warren

Location State: OK Country: US

View the Interpretation Document

Response text:

Mr. David A. Warren

CONAM Inspection, Inc.

1115 West 41st Street

Tulsa, Oklahoma 74105

Dear Mr. Warren:

This is in reply to your letter of March 6, 1972, to Mr. Lance Heverly. With regard to your question on general corrosion, if the transmission line's operating pressure is equal to the pipeline design pressure, in accordance with the design formula contained in Section 192.105, Section 192.485 gives the operator two choices when an area of general corrosion causes reduced wall thickness:

  1. Replace the generally corroded segment of pipe; or
  2. Reduce the operating pressure commensurate with the strength of the remaining pipe wall thickness.

In the case of localized corrosion pitting, it is the operator's responsibility to determine if the remaining wall thickness, taking into account the reinforcing strength provided by the pipe wall surrounding the pit, will withstand its maximum operating pressure. If the strength of the pipe has been reduced by the corrosion, then the operator must either replace or repair the segment involved or assure that his operating pressure is commensurate with the strength of the remaining pipe wall thickness.

As a result of the evaluation of the information presented at the Public Hearing held on July 20, 1971, and other data available to this office, it was decided to withdraw the Notice of Proposed Rule Making (Notice 71-3; Docket No. OPS-5) and leave the regulations in the performance language as contained in the regulations covering corrosion control requirements issued June 25, 1971. Consideration is being given to the recommendations presented at the hearing for a possible new Notice of Proposed Rule Making relating the acceptability of the pipe to a combination of localized corrosion pit depth, width, and length. As Mr. Heverly told you in his telephone conversation, we have no time schedule set for this notice.

Your company has been added to our mailing list to receive copies of our regulations.

Thank you for your interest in our pipeline safety program.


Joseph C. Caldwell


Office of Pipeline Safety

Regulation Sections

Section Subject
192.105 Design formula for steel pipe