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Interpretation Response #PI-71-024 ([Williams Brothers Engineering Co.] [Clinton McClure])

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

Interpretation Response Details

Response Publish Date:

Company Name: Williams Brothers Engineering Co.

Individual Name: Clinton McClure

Location State: OK Country: US

View the Interpretation Document

Response text:

Mr. Clinton McClure
Senior Engineer
Williams Brothers Engineering Co.
Resource Sciences Center
Tulsa, Oklahoma 74103

Dear Mr. McClure:

This is in reply to your letter of December 4, 1970, requesting an interpretation of 49 CFR,
Section 192.611(a).

You state: "It has been our practice for a number of years, where the crossing is not cased, to
place beneath the road or railroad, pipe of greater wall thickness than the line pipe. There may be
a transition pipe of an intermediate wall thickness between the crossing and line pipe in order to
comply with welding standards.

It has been our practice to test the crossing pipe and the transition pipe with the line pipe and to
test it to the same pressure. The test has been 90 percent or more of the SMYS of the line pipe.

In most cases this is less than 90 percent SMYS of the crossing pipe and in some cases less than
90 percent SMYS of the transition pipe.

There are a number of locations where it will become necessary to changes out pipe on each side
of a crossing to comply with the requirements of the new DOT rules and regulations. Will it be
necessary to retest the crossing pipe or re-lay new crossing pipe tested to 90 percent of the
SMYS of the crossing pipe? I have attached example diagrams."

The answer to your question is that it will be necessary either to test as much of the pipe as was
not tested to 90% of SMYS or replace such pipe with the pipe meeting the design and testing
requirements of Part 192 for new pipe in the location, or the maximum operating pressure may be
reduced consistent with the requirements of that Part.

Secondly, you ask: "If pipelines designed, constructed and tested in the future become involved
in class location changes of this nature, will this subsection of the rule and regulations be applied
literally to the "segments" of pipe varying in wall thickness?

The answer to your question is that Section 192.611 will be literally applied to segments of pipe
such as road crossings.

If we can be of further assistance to you, please let us know.

Sincerely,

Joseph C. Caldwell
Director, Acting
Office of Pipeline Safety

Regulation Sections

Section Subject
192.611 Change in class location: Confirmation or revision of maximum allowable operating pressure