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Interpretation Response #PI-77-008 ([Metallurgical Consultants, Inc.] [T. V. Bruno])

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

Interpretation Response Details

Response Publish Date:

Company Name: Metallurgical Consultants, Inc.

Individual Name: T. V. Bruno

Location State: TX Country: US

View the Interpretation Document

Response text:

February 14, 1977

Mr. T. V. Bruno

Metallurgical Consultants, Inc.

P.O. Box 88046

Houston, TX 77004

Dear Mr. Bruno:

This is in reply to your letter of July 30, 1976, requesting aninterpretation of the requirements of 49 CFR Part 195,"Transportation of Liquids by Pipeline," relating to the length of allowable internal undercutting of pipeline welds.

Question: What is the limit of any individual length of undercutting?

Question: Is there a limit of length of undercutting in any given continuous length of weld (e.g., 12 inches, 1/6 thetotal weld length, 8 percent of the total weld length)and if so, what is the limit?

Answer: In regard to the above two questions, Part 195 has incorporated by reference API Standard 1104 for standards of acceptability for welding. Subsection 6.9, Undercutting, of that standard prescribes the limits of undercut. As stated in that standard, where depth of undercut is between 1/64 inch and 1/32inch, the length of any continuous undercut should not exceed 2 inches or 1/6 the length of the specific weld, whichever is smaller.

Consultation with Mr. R. B. Gwinn, Secretary, API-AGAJoint Committee on Oil and Gas Pipe Line Field Welding Practices, had indicated that this requirement asspecified in the 13th edition of API Standard 1104 is in error. Mr. Gwinn has advised that this matter would be corrected in the 14th edition soon to be published and that for undercut depth between 1/64 inch and 1/32 inch the limitation for undercutting length will be 2inches in a continuous weld length of 12 inches or 1/6 of the length, whichever is smaller.

Question: Does Subsection 6.8 of API Standard 1104 include undercutting in determining accumulation of discontinuities?

Answer: The intent of Subsection 6.8 of API Standard 1104 is not only to exclude high-low condition but also undercutting indetermining accumulation of discontinuities. We have been advised that API will also revise this section in the 14th edition of 1104 to clarify this intent.

Upon receipt of this new edition, OPSO will analyze itscontent and proceed to determine if it is appropriatefor incorporation by reference in OPSO's regulations.

I trust that this adequately responds to your inquiry.


Cesar DeLeon

Acting Director

Office of Pipeline

Safety Operations

Regulation Sections

Section Subject
195.1 Which pipelines are covered by this Part?